An absorbing microwave micro-solid-phase extraction device used in non-polar solvent microwave-assisted extraction for the determination of organophosphorus pesticides.

PubMed

Wang, Ziming; Zhao, Xin; Xu, Xu; Wu, Lijie; Su, Rui; Zhao, Yajing; Jiang, Chengfei; Zhang, Hanqi; Ma, Qiang; Lu, Chunmei; Dong, Deming

2013-01-14

A single-step extraction-cleanup method, including microwave-assisted extraction (MAE) and micro-solid-phase extraction (μ-SPE), was developed for the extraction of ten organophosphorus pesticides in vegetable and fruit samples. Without adding any polar solvent, only one kind of non-polar solvent (hexane) was used as extraction solvent in the whole extraction step. Absorbing microwave μ-SPE device, was prepared by packing activated carbon with microporous polypropylene membrane envelope, and used as not only the sorbent in μ-SPE, but also the microwave absorption medium. Some experimental parameters effecting on extraction efficiency was investigated and optimized. 1.0 g of sample, 8 mL of hexane and three absorbing microwave μ-SPE devices were added in the microwave extraction vessel, the extraction was carried out under 400 W irradiation power at 60°C for 10 min. The extracts obtained by MAE-μ-SPE were directly analyzed by GC-MS without any clean-up process. The recoveries were in the range of 93.5-104.6%, and the relative standard deviations were lower than 8.7%. Copyright © 2012 Elsevier B.V. All rights reserved.

Ultrasound-assisted extraction and solid-phase extraction for the simultaneous determination of five amide herbicides in fish samples by gas chromatography with electron capture detection.

PubMed

Qu, Zhipeng; Bai, Xiuzhi; Zhang, Ting; Yang, Zhaoguang

2017-03-01

An efficient sample extraction and clean-up method was developed for simultaneous determination of five amide herbicides (alachlor, acetochlor, propisochlor, metazachlor, and butachlor) in fish samples. The protocol consisted of ultrasound-assisted solvent extraction and solid-phase extraction clean-up. In detail, aliquots of homogenized fish flesh were thoroughly mixed with 20 mL of n-hexane and then extracted with ultrasonication for 40 min. Each sample was centrifuged and the supernatant was collected for the subsequent clean-up. For the sample preparation, the above supernatant was processed with a C 18 column with 3 mL of dichloromethane/n-hexane (1:1, v/v) as the eluant. Then the samples were analyzed by gas chromatography with electron capture detection. The correlation coefficients of the five calibration curves were 0.9976-0.9998 (n = 3). The limits of detection (S/N = 3, n = 11) and limits of quantification (S/N = 10, n = 11) were 0.19-0.42 and 0.63-1.39 μg/kg, respectively. The recoveries of this method were 71.2-92.6% with good precision (<4.7% relative standard deviations, n = 6). The developed method was successfully applied to monitor the five amide herbicides in fish samples collected from different cities. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Analysis of imazaquin in soybeans by solid-phase extraction and high-performance liquid chromatography.

PubMed

Guo, C; Hu, J-Y; Chen, X-Y; Li, J-Z

2008-02-01

An analytical method for the determination imazaquin residues in soybeans was developed. The developed liquid/liquid partition and strong anion exchange solid-phase extraction procedures provide the effective cleanup, removing the greatest number of sample matrix interferences. By optimizing mobile-phase pH water/acetonitrile conditions with phosphoric acid, using a C-18 reverse-phase chromatographic column and employing ultraviolet detection, excellent peak resolution was achieved. The combined cleanup and chromatographic method steps reported herein were sensitive and reliable for determining the imazaquin residues in soybean samples. This method is characterized by recovery >88.4%, precision <6.7% CV, and sensitivity of 0.005 ppm, in agreement with directives for method validation in residue analysis. Imazaquin residues in soybeans were further confirmed by high performance liquid chromatography-mass spectrometry (LC-MS). The proposed method was successfully applied to the analysis of imazaquin residues in soybean samples grown in an experimental field after treatments of imazaquin formulation.

Hot Chili Peppers: Extraction, Cleanup, and Measurement of Capsaicin

NASA Astrophysics Data System (ADS)

Huang, Jiping; Mabury, Scott A.; Sagebiel, John C.

2000-12-01

Capsaicin, the pungent ingredient of the red pepper or Capsicum annuum, is widely used in food preparation. The purpose of this experiment was to acquaint students with the active ingredients of hot chili pepper (capsaicin and dihydrocapsaicin), the extraction, cleanup, and analysis of these chemicals, as a fun and informative analytical exercise. Fresh peppers were prepared and extracted with acetonitrile, removing plant co-extractives by addition to a C-18 solid-phase extraction cartridge. Elution of the capsaicinoids was accomplished with a methanol-acetic acid solution. Analysis was completed by reverse-phase HPLC with diode-array or variable wavelength detection and calibration with external standards. Levels of capsaicin and dihydrocapsaicin were typically found to correlate with literature values for a specific hot pepper variety. Students particularly enjoyed relating concentrations of capsaicinoids to their perceived valuation of "hotness".

Determination of pesticides in sewage sludge from an agro-food industry using QuEChERS extraction followed by analysis with liquid chromatography-tandem mass spectrometry.

PubMed

Ponce-Robles, Laura; Rivas, Gracia; Esteban, Belen; Oller, Isabel; Malato, Sixto; Agüera, Ana

2017-10-01

An analytical method was developed and validated for the determination of ten pesticides in sewage sludge coming from an agro-food industry. The method was based on the application of Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) extraction for solid sewage sludge and SPE extraction for sludge aqueous phase, followed by liquid chromatography (LC) coupled to hybrid quadrupole/linear ion trap mass spectrometry (QqLIT-MS). The QuEChERS method was reported 14 years ago and nowadays is mainly applied to the analysis of pesticides in food. More recent applications have been reported in other matrices as sewage sludge, but the complexity of the matrix makes necessary the optimization of the cleanup step to improve the efficiency of the analysis. With this aim, several dispersive solid-phase extraction cleanup sorbents were tested, choosing C18 + PSA as a d-SPE sorbent. The proposed method was satisfactorily validated for most compounds investigated, showing recoveries higher than 80% in most cases, with the only exception of prochloraz (71%) at low concentration level. Limits of quantification were lower than 40 ng l -1 in the aqueous phase and below 40 ng g -1 in the solid phase for the majority of the analytes. The method was applied to solid sludge and the sludge aqueous phase coming from an agro-food industry which processes fruits and vegetables. Graphical abstract Application of LC/MS/MS advanced analytical techniques for determination of pesticides contained in sewage sludge.

Simultaneous Solid Phase Extraction and Derivatization of Aliphatic Primary Amines Prior to Separation and UV-Absorbance Detection

PubMed Central

Felhofer, Jessica L.; Scida, Karen; Penick, Mark; Willis, Peter A.; Garcia, Carlos D.

2013-01-01

To overcome the problem of poor sensitivity of capillary electrophoresis-UV absorbance for the detection of aliphatic amines, a solid phase extraction and derivatization scheme was developed. This work demonstrates successful coupling of amines to a chromophore immobilized on a solid phase and subsequent cleavage and analysis. Although the analysis of many types of amines is relevant for myriad applications, this paper focuses on the derivatization and separation of amines with environmental relevance. This work aims to provide the foundations for future developments of an integrated sample preparation microreactor capable of performing simultaneous derivatization, preconcentration, and sample cleanup for sensitive analysis of primary amines. PMID:24054648

Determination of alkylphenols and 17beta-estradiol in fish homogenate. Extraction and clean-up strategies.

PubMed

Navarro, P; Bustamante, J; Vallejo, A; Prieto, A; Usobiaga, A; Arrasate, S; Anakabe, E; Puy-Azurmendi, E; Zuloaga, O

2010-09-17

The determination of target analytes such as nonyl- and octylphenols and 17beta-estradiol in fish homogenate require of solid-liquid extraction step. In this work microwave-assisted extraction (MAE) and focused-ultrasound liquid extraction (FUSLE) were studied as two different alternatives for extraction of the target compounds in zebrafish (Danio rerio) homogenate. In this work solid phase extraction (SPE) using 5-g and 10-g Florisil cartridges and gel permeation chromatography (GPC) were studied for the clean-up of the MAE and FUSLE extracts due to the non-selective extraction step. Although good recoveries were obtained both for SPE (106% and 126% range) and GPC (79% and 100% range) clean-up procedures, cleaner chromatograms were obtained after SPE and finally 5-g Florisil cartridges were tested since no improvement was observed when 10-g Florisil cartridges were used. Under optimized clean-up conditions, MAE and FUSLE provided comparable results for 4nOP and NP, while more accurate results were obtained for 4tOP and E2 after FUSLE. Finally, the method was applied to the determination of alkylphenols and 17beta-estradiol in zebrafish homogenate that had been exposed to known concentrations of the target analytes. In the case of alkylphenols two different isomers of nonyl- and octylphenol (4-(3',6'-dimethyl-3'-hepthyl)phenol, 363-NP, and 4-(3'-methyl-3'-hepthyl)phenol, 33-OP) were studied. 2010 Elsevier B.V. All rights reserved.

Novel approach to microwave-assisted extraction and micro-solid-phase extraction from soil using graphite fibers as sorbent.

PubMed

Xu, Li; Lee, Hian Kee

2008-05-30

A single-step extraction-cleanup procedure involving microwave-assisted extraction (MAE) and micro-solid-phase extraction (micro-SPE) has been developed for the analysis of polycyclic aromatic hydrocarbons (PAHs) from soil samples. Micro-SPE is a relatively new extraction procedure that makes use of a sorbent enclosed within a sealed polypropylene membrane envelope. In the present work, for the first time, graphite fiber was used as a sorbent material for extraction. MAE-micro-SPE was used to cleanup sediment samples and to extract and preconcentrate five PAHs in sediment samples prepared as slurries with addition of water. The best extraction conditions comprised of microwave heating at 50 degrees C for a duration of 20 min, and an elution (desorption) time of 5 min using acetonitrile with sonication. Using gas chromatography (GC)-flame ionization detection (FID), the limits of detection (LODs) of the PAHs ranged between 2.2 and 3.6 ng/g. With GC-mass spectrometry (MS), LODs were between 0.0017 and 0.0057 ng/g. The linear ranges were between 0.1 and 50 or 100 microg/g for GC-FID analysis, and 1 and 500 or 1000 ng/g for GC-MS analysis. Granular activated carbon was also used for the micro-SPE device but was found to be not as efficient in the PAH extraction. The MAE-micro-SPE method was successfully used for the extraction of PAHs in river and marine sediments, demonstrating its applicability to real environmental solid matrixes.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This interim notice covers the following: extractable organic halides in solids, total organic halides, analysis by gas chromatography/Fourier transform-infrared spectroscopy, hexadecane extracts for volatile organic compounds, GC/MS analysis of VOCs, GC/MS analysis of methanol extracts of cryogenic vapor samples, screening of semivolatile organic extracts, GPC cleanup for semivolatiles, sample preparation for GC/MS for semi-VOCs, analysis for pesticides/PCBs by GC with electron capture detection, sample preparation for pesticides/PCBs in water and soil sediment, report preparation, Florisil column cleanup for pesticide/PCBs, silica gel and acid-base partition cleanup of samples for semi-VOCs, concentrate acid wash cleanup, carbon determination in solids using Coulometrics` CO{submore » 2} coulometer, determination of total carbon/total organic carbon/total inorganic carbon in radioactive liquids/soils/sludges by hot persulfate method, analysis of solids for carbonates using Coulometrics` Model 5011 coulometer, and soxhlet extraction.« less

Determination of the cyanobacterial toxin cylindrospermopsin in algal food supplements.

PubMed

Liu, H; Scott, P M

2011-06-01

For the analysis of blue-green algal food supplements for cylindrospermopsin (CYN), a C18 solid-phase extraction column and a polygraphitized carbon solid-phase extraction column in series was an effective procedure for the clean-up of extracts. Determination of CYN was by liquid chromatography with ultraviolet light detection. At extract spiking levels of CYN equivalent to 25-500 µg g(-1), blue-green algal supplement recoveries were in the range 70-90%. CYN was not detected in ten samples of food supplements and one chocolate product, all containing blue-green algae. The limit of detection for the method was 16 µg g(-1), and the limit of quantification was 52 µg g(-1).

Comparison of solid phase extraction, saponification and gel permeation chromatography for the clean-up of microwave-assisted biological extracts in the analysis of polycyclic aromatic hydrocarbons.

PubMed

Navarro, P; Cortazar, E; Bartolomé, L; Deusto, M; Raposo, J C; Zuloaga, O; Arana, G; Etxebarria, N

2006-09-22

The feasibility of different clean-up procedures was studied for the determination of polycyclic aromatic hydrocarbons (PAHs) in biota samples such as oysters, mussels and fish liver. In this sense, once the samples were extracted--essentially with acetone and in a microwave system--and before they could be analysed by gas chromatography-mass spectrometry (GC-MS), three different approaches were studied for the clean-up step: solid phase extraction (SPE), microwave-assisted saponification (MAS) and gel permeation chromatography (GPC). The main aim of this work was to maximise the recoveries of PAHs and to minimise the presence of interfering compounds in the last extract. In the case of SPE, Florisil cartridges of 1, 2 and 5 g, and silica cartridges of 5 g were studied. In that case, and with oysters and mussels, microwave-assisted extraction and 5 g Florisil cartridges provided good results. In addition, the concentrations obtained for Standard Reference Material (SRM) NIST 2977 (mussel tissue) were in good agreement with the certified values. In the case of microwave-assisted saponification, the extracts were not as clean as those obtained with 5 g Florisil and this fact lead to overestimate the concentration of the heaviest PAHs. Finally, the cleanest extracts were obtained by GPC. The method was successfully applied to mussels, oysters and hake liver, and the results obtained for NIST 2977 (mussel tissue) were within the confidence interval of the certified reference material for most of the certified analytes.

Determination of organochlorine pesticide and polychlorinated biphenyl residues in fatty fish by tandem solid-phase extraction cleanup.

PubMed

Schenck, F J; Calderon, L; Podhorniak, L V

1996-01-01

A rapid, multiresidue solid-phase extraction (SPE) technique for determination of organochlorine pesticide and polychlorinated biphenyl (PCB) residues in nonfatty fish was modified for use with fatty fish. In the modified procedures, samples are extracted with acetonitrile, and the extract is cleaned up with both C18 and Florisil SPE columns. Residues are determined by gas chromatography with electron capture detection. The original method was modified for use with fatty fish by reducing the amount of tissue extracted and by using an improved Florisil SPE cleanup. Recovery data are presented for 24 fortified organochlorine pesticide residues (0.12 ppm) and 3 fortified PCB residues (0.80 ppm) from flounder, bluefish, and shad samples, which contained 0.8, 5.4, and 22.6% fat, respectively. For the 3 types of fish, recoveries of 23 of 24 fortified organochlorine pesticide residues ranged from 55 to 129%, and recoveries of 3 fortified PCB residues ranged from 55 to 104%. There were no significant differences in recovery based on fish species and/or fat content for the majority of residues studied. This SPE method and the official AOAC method yielded comparable results for fish containing incurred organochlorine residues.

Improved sample extraction and clean-up for the GC-MS determination of BADGE and BFDGE in vegetable oil.

PubMed

Brede, C; Skjevrak, I; Herikstad, H; Anensen, E; Austvoll, R; Hemmingsen, T

2002-05-01

A straightforward method was established for the determination of migration contaminants in olive oil with a special focus on the two can-coating migration compounds bisphenol A diglycidyl ether (BADGE) and bisphenol F diglycidyl ether (BFDGE). The preferred sample preparation was a single liquid-liquid extraction of compounds from the oil into 20% (v/v) methanol in acetonitrile, followed by clean-up with solid-phase extraction on aminopropyl bonded to silica. This purification procedure selectively removed all free fatty acids from the extracts without removing phenolic compounds of interest. The solid-phase extraction columns were used many times by implementing a procedure of washing out the strongly retained fatty acids with 2% acetic acid in methanol. Gas chromatography coupled with full scan (m/z 33-700) electron ionization mass spectrometry was used for the determination of several model compounds in olive oil samples. BADGE and BFDGE could be determined in the 0.05-2 mg kg(-1) range in oil samples with a relative SD of <6% (six replicates). The method was used in an enforcement campaign for the Norwegian Food Control Authority to analyse vegetable oil samples from canned fish-in-oil.

Residue analysis of sixty pesticides in red swamp crayfish using QuEChERS with high-performance liquid chromatography-tandem mass spectrometry

USDA-ARS?s Scientific Manuscript database

In this study, a multi-residue analytical method using QuEChERS extraction and dispersive solid-phase extraction (d-SPE) cleanup followed by high-performance liquid chromatography–tandem mass spectrometry (HPLC-MS/MS) was developed for rapid determination of 60 pesticide residues in whole crayfish a...

Glufosinate ammonium clean-up procedure from water samples using SPE

NASA Astrophysics Data System (ADS)

Tayeb M., A.; Ismail B., S.; Mardiana-Jansar, K.; Ta, Goh Choo; Agustar, Hani Kartini

2015-09-01

For the determination of glufosinate ammonium residue in soil and water samples, different solid phase extraction (SPE) sorbent efficiency was studied. Four different SPE sorbents i.e.: CROMABOND PS-H+, CROMABOND PS-OH-, ISOLUTE ENV+, Water Sep-Pak and OASIS HLB were used. Sample clean-up performance was evaluated using high performance liquid chromatography (Agilent 1220 infinity LC) with fluorescence detector. Detection of FMO-derivatives was done at λ ex = 260 nm and λ em= 310 nm. OASIS HLB column was the most suitable for the clean-up in view of the overall feasibility of the analysis.

Liquid chromatographic determination of the cyanobacterial toxin beta-n-methylamino-L-alanine in algae food supplements, freshwater fish, and bottled water.

PubMed

Scott, Peter M; Niedzwiadek, Barbara; Rawn, Dorothea F K; Lau, Ben P-Y

2009-08-01

Beta-N-Methylamino-L-alanine (BMAA) is a neurotoxin originally found in cycad seeds and now known to be produced by many species of freshwater and marine cyanobacteria. We developed a method for its determination in blue-green algae (BGA) food supplements, freshwater fish, and bottled water by using a strong cation-exchange, solid-phase extraction column for cleanup after 0.3 M trichloroacetic acid extraction of BGA supplements and fish. Bottled water was applied directly onto the solid-phase extraction column. For analysis of carbonated water, sonication and pH adjustment to 1.5 were needed. To determine protein-bound BMAA, the protein pellet left after extraction of the BGA supplement and fish was hydrolyzed by boiling with 6 M hydrochloric acid; BMAA was cleaned up on a C18 column and a strong cation-exchange, solid-phase extraction column. Determination of BMAA was by liquid chromatography of the fluorescent derivative formed with 9-fluorenylmethyl chloroformate. The method was validated by recovery experiments using spiking levels of 1.0 to 10 microg/g for BGA supplements, 0.5 to 5.0 microg/g for fish, and 0.002 microg/g for bottled water; mean recoveries were in the range of 67 to 89% for BGA supplements and fish, and 59 to 92% for bottled water. Recoveries of BMAA from spiked extracts of hydrolyzed protein from BGA supplements and fish ranged from 66 to 83%. The cleanup developed provides a useful method for surveying foods and supplements for BMAA and protein-bound BMAA.

Primary secondary amine as a sorbent material in dispersive solid-phase extraction clean-up for the determination of indicator polychlorinated biphenyls in environmental water samples by gas chromatography with electron capture detection.

PubMed

Guo, Yuanming; Hu, Hongmei; Li, Tiejun; Xue, Lijian; Zhang, Xiaoning; Zhong, Zhi; Zhang, Yurong; Jin, Yanjian

2017-08-01

A simple, rapid, and novel method has been developed and validated for determination of seven indicator polychlorinated biphenyls in water samples by gas chromatography with electron capture detection. 1 L of water samples containing 30 g of anhydrous sodium sulfate was first liquid-liquid extracted with an automated Jipad-6XB vertical oscillator using n-hexane/dichloromethane (1:1, v/v). The concentrated extract was cleaned up by dispersive solid-phase extraction with 100 mg of primary secondary amine as sorbent material. The linearity of this method ranged from 1.25 to 100 μg/L, with regression coefficients ranging between 0.9994 and 0.9999. The limits of detection were in the ng/L level, ranging between 0.2 and 0.3 ng/L. The recoveries of seven spiked polychlorinated biphenyls with external calibration method at different concentration levels in tap water, lake water, and sea water were in the ranges of 85-112, 76-116, and 72-108%, respectively, and with relative standard deviations of 3.3-4.5, 3.4-5.6, and 3.1-4.8% (n = 5), respectively. The performance of the proposed method was compared with traditional liquid-liquid extraction and solid-phase extraction clean-up methods, and comparable efficiencies were obtained. It is concluded that this method can be successfully applied for the determination of polychlorinated biphenyls in different water samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Micro versus macro solid phase extraction for monitoring water contaminants: a preliminary study using trihalomethanes.

PubMed

Alexandrou, Lydon D; Spencer, Michelle J S; Morrison, Paul D; Meehan, Barry J; Jones, Oliver A H

2015-04-15

Solid phase extraction is one of the most commonly used pre-concentration and cleanup steps in environmental science. However, traditional methods need electrically powered pumps, can use large volumes of solvent (if multiple samples are run), and require several hours to filter a sample. Additionally, if the cartridge is open to the air volatile compounds may be lost and sample integrity compromised. In contrast, micro cartridge based solid phase extraction can be completed in less than 2 min by hand, uses only microlitres of solvent and provides comparable concentration factors to established methods. It is also an enclosed system so volatile components are not lost. The sample can also be eluted directly into a detector (e.g. a mass spectrometer) if required. However, the technology is new and has not been much used for environmental analysis. In this study we compare traditional (macro) and the new micro solid phase extraction for the analysis of four common volatile trihalomethanes (trichloromethane, bromodichloromethane, dibromochloromethane and tribromomethane). The results demonstrate that micro solid phase extraction is faster and cheaper than traditional methods with similar recovery rates for the target compounds. This method shows potential for further development in a range of applications. Copyright © 2015 Elsevier B.V. All rights reserved.

An improved dispersive solid-phase extraction clean-up method for the gas chromatography-negative chemical ionisation tandem mass spectrometric determination of multiclass pesticide residues in edible oils.

PubMed

Deme, Pragney; Azmeera, Tirupathi; Prabhavathi Devi, B L A; Jonnalagadda, Padmaja R; Prasad, R B N; Vijaya Sarathi, U V R

2014-01-01

An improved sample preparation using dispersive solid-phase extraction clean-up was proposed for the trace level determination of 35 multiclass pesticide residues (organochlorine, organophosphorus and synthetic pyrethroids) in edible oils. Quantification of the analytes was carried out by gas chromatography-mass spectrometry in negative chemical ionisation mode (GC-NCI-MS/MS). The limit of detection and limit of quantification of residues were in the range of 0.01-1ng/g and 0.05-2ng/g, respectively. The analytes showed recoveries between 62% and 110%, and the matrix effect was observed to be less than 25% for most of the pesticides. Crude edible oil samples showed endosulfan isomers, p,p'-DDD, α-cypermethrin, chlorpyrifos, and diazinon residues in the range of 0.56-2.14ng/g. However, no pesticide residues in the detection range of the method were observed in refined oils. Copyright © 2013 Elsevier Ltd. All rights reserved.

Screening of a Combinatorial Library of Organic Polymers for the Solid-Phase Extraction of Patulin from Apple Juice

PubMed Central

Giovannoli, Cristina; Spano, Giulia; Di Nardo, Fabio; Anfossi, Laura; Baggiani, Claudio

2017-01-01

Patulin is a water-soluble mycotoxin produced by several species of fungi. Governmental bodies have placed it under scrutiny for its potential negative health effects, and maximum residue limits are fixed in specific food matrices to protect consumers’ health. Confirmatory analysis of patulin in complex food matrices can be a difficult task, and sample clean-up treatments are frequently necessary before instrumental analyses. With the aim of simplifying the clean-up step, we prepared a 256-member combinatorial polymeric library based on 16 functional monomers, four cross-linkers and four different porogenic solvents. The library was screened for the binding towards patulin in different media (acetonitrile and citrate buffer at pH 3.2), with the goal of identifying polymer formulations with good binding properties towards the target compound. As a proof of concept, a methacrylic acid-co-pentaerithrytole tetraacrylate polymer prepared in chloroform was successfully used as a solid-phase extraction material for the clean-up and extraction of patulin from apple juice. Clean chromatographic patterns and acceptable recoveries were obtained for juice spiked with patulin at concentration levels of 25 (64 ± 12%), 50 (83 ± 5.6%) and 100 μg L−1 (76 ± 4.5%). The within-day and between-day reproducibility evaluated at a concentration level of 25 μg L−1 were 5.6 and 7.6%, respectively. PMID:28531103

A simple and selective method for determination of phthalate biomarkers in vegetable samples by high pressure liquid chromatography-electrospray ionization-tandem mass spectrometry.

PubMed

Zhou, Xi; Cui, Kunyan; Zeng, Feng; Li, Shoucong; Zeng, Zunxiang

2016-06-01

In the present study, solid-phase extraction cartridges including silica reversed-phase Isolute C18, polymeric reversed-phase Oasis HLB and mixed-mode anion-exchange Oasis MAX, and liquid-liquid extractions with ethyl acetate, n-hexane, dichloromethane and its mixtures were compared for clean-up of phthalate monoesters from vegetable samples. Best recoveries and minimised matrix effects were achieved using ethyl acetate/n-hexane liquid-liquid extraction for these target compounds. A simple and selective method, based on sample preparation by ultrasonic extraction and liquid-liquid extraction clean-up, for the determination of phthalate monoesters in vegetable samples by liquid chromatography/electrospray ionisation-tandem mass spectrometry was developed. The method detection limits for phthalate monoesters ranged from 0.013 to 0.120 ng g(-1). Good linearity (r(2)>0.991) between MQLs and 1000× MQLs was achieved. The intra- and inter-day relative standard deviation values were less than 11.8%. The method was successfully used to determine phthalate monoester metabolites in the vegetable samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

Determination of parabens and endocrine-disrupting alkylphenols in soil by gas chromatography-mass spectrometry following matrix solid-phase dispersion or in-column microwave-assisted extraction: a comparative study.

PubMed

Pérez, R A; Albero, B; Miguel, E; Sánchez-Brunete, C

2012-03-01

Two rapid methods were evaluated for the simultaneous extraction of seven parabens and two alkylphenols from soil based on matrix solid-phase dispersion (MSPD) and microwave-assisted extraction (MAE). Soil extracts were derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide and analyzed by gas chromatography with mass spectrometry. Extraction and clean-up of samples were carried out by both methods in a single step. A glass sample holder, inside the microwave cell, was used in MAE to allow the simultaneous extraction and clean-up of samples and shorten the MAE procedure. The detection limits achieved by MSPD were lower than those obtained by MAE because the presence of matrix interferences increased with this extraction method. The extraction yields obtained by MSPD and MAE for three different types of soils were compared. Both procedures showed good recoveries and sensitivity for the determination of parabens and alkylphenols in two of the soils assayed, however, only MSPD yielded good recoveries with the other soil. Finally, MSPD was applied to the analysis of soils collected in different sites of Spain. In most of the samples analyzed, methylparaben and butylparaben were detected at levels ranging from 1.21 to 8.04 ng g(-1) dry weight and 0.48 to 1.02 ng g(-1) dry weight, respectively.

Automated Mini-Column Solid-Phase Extraction Cleanup for High-Throughput Analysis of Chemical Contaminants in Foods by Low-Pressure Gas Chromatography-Tandem Mass Spectrometry.

PubMed

Lehotay, Steven J; Han, Lijun; Sapozhnikova, Yelena

2016-01-01

This study demonstrated the application of an automated high-throughput mini-cartridge solid-phase extraction (mini-SPE) cleanup for the rapid low-pressure gas chromatography-tandem mass spectrometry (LPGC-MS/MS) analysis of pesticides and environmental contaminants in QuEChERS extracts of foods. Cleanup efficiencies and breakthrough volumes using different mini-SPE sorbents were compared using avocado, salmon, pork loin, and kale as representative matrices. Optimum extract load volume was 300 µL for the 45 mg mini-cartridges containing 20/12/12/1 (w/w/w/w) anh. MgSO 4 /PSA (primary secondary amine)/C 18 /CarbonX sorbents used in the final method. In method validation to demonstrate high-throughput capabilities and performance results, 230 spiked extracts of 10 different foods (apple, kiwi, carrot, kale, orange, black olive, wheat grain, dried basil, pork, and salmon) underwent automated mini-SPE cleanup and analysis over the course of 5 days. In all, 325 analyses for 54 pesticides and 43 environmental contaminants (3 analyzed together) were conducted using the 10 min LPGC-MS/MS method without changing the liner or retuning the instrument. Merely, 1 mg equivalent sample injected achieved <5 ng g -1 limits of quantification. With the use of internal standards, method validation results showed that 91 of the 94 analytes including pairs achieved satisfactory results (70-120 % recovery and RSD ≤ 25 %) in the 10 tested food matrices ( n  = 160). Matrix effects were typically less than ±20 %, mainly due to the use of analyte protectants, and minimal human review of software data processing was needed due to summation function integration of analyte peaks. This study demonstrated that the automated mini-SPE + LPGC-MS/MS method yielded accurate results in rugged, high-throughput operations with minimal labor and data review.

Simultaneous determination of a variety of endocrine disrupting compounds in carrot, lettuce and amended soil by means of focused ultrasonic solid-liquid extraction and dispersive solid-phase extraction as simplified clean-up strategy.

PubMed

Mijangos, L; Bizkarguenaga, E; Prieto, A; Fernández, L A; Zuloaga, O

2015-04-10

The present study is focused on the development of an analytical method based on focused ultrasonic solid-liquid extraction (FUSLE) followed by dispersive solid-phase extraction (dSPE) clean-up and liquid chromatography-triple quadrupole tandem mass spectrometry (LC-MS/MS) optimised for the simultaneous analysis of certain endocrine disrupting compounds (EDCs), including alkylphenols (APs), bisphenol A (BPA), triclosan (TCS) and several hormones and sterols in vegetables (lettuce and carrot) and amended soil samples. Different variables affecting the chromatographic separation, the electrospray ionisation and mass spectrometric detection were optimised in order to improve the sensitivity of the separation and detection steps. Under the optimised extraction conditions (sonication of 5min at 33% of power with pulse times on of 0.8s and pulse times off of 0.2s in 10mL of n-hexane:acetone (30:70, v:v) mixture using an ice bath), different dSPE clean-up sorbents, such as Florisil, Envi-Carb, primary-secondary amine bonded silica (PSA) and C18, or combinations of them were evaluated for FUSLE extracts before LC-MS/MS. Apparent recoveries and precision in terms of relative standard deviation (RSDs %) of the method were determined at two different fortification levels (according to the matrix and the analyte) and values in the 70-130% and 2-27% ranges, respectively, were obtained for most of the target analytes and matrices. Matrix-matched calibration approach and the use of labelled standards as surrogates were needed for the properly quantification of most analytes and matrices. Method detection limits (MDLs), estimated with fortified samples, in the ranges of 0.1-100ng/g for carrot, 0.2-152ng/g for lettuce and 0.9-31ng/g for amended soil were obtained. The developed methodology was applied to the analysis of 11 EDCs in both real vegetable bought in a local market and in compost (from a local wastewater treatment plant, WWTP) amended soil samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Determination of mycotoxins produced by Fusarium isolates from banana fruits by capillary gas chromatography and high-performance liquid chromatography.

PubMed

Jiménez, M; Mateo, R

1997-08-22

A method of analysis for trichothecenes (nivalenol, deoxynivalenol, 3- and 15-acetyldeoxynivalenol, diacetoxyscirpenol, neosolaniol, T-2 tetraol, T-2 and HT-2 toxins), zearalenone and zearalenols, and another method for determination of fumonisin B1 are described and applied to cultures of Fusarium isolated from bananas. Both methods were adapted from different techniques of extraction, clean-up and determination of these mycotoxins. The first method involves extraction with methanol-1% aqueous sodium chloride, clean-up of extracts by partition with hexane and dichloromethane, additional solid reversed-phase clean-up and analysis of two eluates by both high-performance liquid chromatography with ultraviolet detection and capillary gas chromatography. The method for fumonisin B1 implies extraction with aqueous methanol, concentration, clean-up with water and methanol on Amberlite XAD-2 column, formation of a fluorescent 4-fluoro-7-nitrobenzofurazan derivative and analysis by high-performance liquid chromatography with fluorescence detection. Both procedures give good limits of detection and recoveries, and are considered suitable for the detection and quantification of the studied toxins in corn and rice cultures of Fusarium spp. isolated from banana fruits.

Simultaneous determination of gaseous and particulate carbonyls in air by coupling micellar electrokinetic capillary chromatography with molecular imprinting solid-phase extraction.

PubMed

Sun, Hui; Lai, Jia-Ping; Fung, Ying Sing

2014-09-05

A novel method coupling molecular imprinting solid-phase extraction (MISPE) and micellar electrokinetic capillary chromatography (MEKC) was developed to enable the hourly determination of low level of ambient carbonyls, and study their partition between gaseous phase and particulate phase. With 2,4-dinitroaniline (DNAN) as dummy imprinting template, the unreacted 2,4-Dinitrophenylhydrazine (DNPH) in sampling solution could be removed effectively using MISPE, and an average recovery of 97±5.3% (n=5) for the carbonyl-DNPH derivatives was achieved. Owing to the high enrichment due to sample clean-up, and the improvement of MEKC separation efficiency, many low abundant carbonyls could be detected by hourly in the field study. Copyright © 2014 Elsevier B.V. All rights reserved.

Determination of etoxazole residues in fruits and vegetables by SPE clean-up and HPLC-DAD.

PubMed

Malhat, Farag; Badawy, Hany; Barakat, Dalia; Saber, Ayman

2013-01-01

A method for determination of etoxazole residues in apples, strawberries and green beans was developed and validated. The analyte was extracted with acetonitrile from foodstuff and a charcoal-celite cartridge was used for clean-up of raw extracts. Reversed phase high performance liquid chromatography with photodiode array detector (HPLC-DAD) was used for the determination and quantification of etoxazole residues in the studied samples. The calibration graphs of etoxazole in a solvent or three blank matrixes were linear within the tested intervals 0.01-2 mg L(-1), with correlation coefficient of determination >0.999. The combined solid phase extraction (SPE) clean-up and the chromatographic method steps were sensitive and reliable for simultaneous determination of etoxazole residues in the studied samples. The average recoveries of etoxazole in the tested foodstuffs were between 93.4 to 102% at spiking levels of 0.01, 0.10, and 0.50 mg kg(-1), with relative standard deviations ranging from 2.8 to 4.7%, in agreement with directives for method validation in residue analyses. The limit of detection (LOD) of the HPLC-DAD system was 100 pg. The limit of quantification of the entire method was 0.01 mg kg(-1).

Preparation and quantification of the total phenolic products in Citrus fruit using solid-phase extraction coupled with high-performance liquid chromatography with diode array and UV detection.

PubMed

Zeng, Honglian; Liu, Zhenli; Zhao, Siyu; Shu, Yisong; Song, Zhiqian; Wang, Chun; Dong, Yunzhuo; Ning, Zhangchi; He, Dan; Wang, Menglei; Lu, Cheng; Liu, Yuanyan; Lu, Aiping

2016-10-01

Citrus fruit is an important health-promoting food that is rich in dietary phenolic metabolites. Traditional Chinese medicines, such as Zhishi and Zhiqiao, come from young and immature fruits of Citrus cultivars. The preparation of diversified bioactive phenolic products and establishment of the corresponding quality control methodology are challenging and necessary. In the current study, four types of solid-phase extraction sorbents for the enrichment and clean-up of the phenolic matrix were evaluated. A solid-phase extraction column coated with Strata-X was finally used in the procedure. Twenty phenolic compounds were selected to evaluate the extraction performances of the sorbents using high-performance liquid chromatography analysis. Under the optimized conditions, good linearities were obtained with R 2 more than 0.9996 for all analytes with LODs of 0.04-1.012 μg/g. Intra- and interday relative standard deviation values were less than 3%, and the recovery was equal to or higher than 90.02%. Compared to non-solid-phase extraction process, the content of total phenolic products was elevated 35.55-68.48% with solid-phase extraction. Finally, the developed and validated method was successfully applied to the discrimination of Zhishi samples from different species as well as Zhishi and Zhiqiao samples in different development stages. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Magnetic dummy molecularly imprinted polymers based on multi-walled carbon nanotubes for rapid selective solid-phase extraction of 4-nonylphenol in aqueous samples.

PubMed

Rao, Wei; Cai, Rong; Yin, Yuli; Long, Fang; Zhang, Zhaohui

2014-10-01

In this paper, a highly selective sample clean-up procedure combining magnetic dummy molecular imprinting with solid-phase extraction was developed for rapid separation and determination of 4-nonylphenol (NP) in the environmental water samples. The magnetic dummy molecularly imprinted polymers (mag-DMIPs) based on multi-walled carbon nanotubes were successfully synthesized with a surface molecular imprinting technique using 4-tert-octylphenol as the dummy template and tetraethylorthosilicate as the cross-linker. The maximum adsorption capacity of the mag-DMIPs for NP was 52.4 mg g(-1) and it took about 20 min to achieve the adsorption equilibrium. The mag-DMIPs exhibited the specific selective adsorption toward NP. Coupled with high performance liquid chromatography analysis, the mag-DMIPs were used to extract solid-phase and detect NP in real water samples successfully with the recoveries of 88.6-98.1%. Copyright © 2014 Elsevier B.V. All rights reserved.

High-performance liquid chromatographic characterization of some medical plant extracts used in cosmetic formulas.

PubMed

Schulz, H; Albroscheit, G

1988-06-17

Rapid and reliable methods are presented for the characterization of biologically active and/or characteristic constituents in aqueous extracts of Hamamelis virginiana, Matricaria chamomilla, Achillea millefolium, Thymus vulgaris, Althaea officinalis and Cinchonia spp. Prior to high-performance liquid chromatographic (HPLC) separation a clean-up step was performed using a solid-phase extraction system. The purified extracts were analysed by HPLC coupled with a diode-array detector and a fluorescence detector. In some instances, previously unreported components of the aqueous plant extracts were found.

Application of an activated carbon-based support for magnetic solid phase extraction followed by spectrophotometric determination of tartrazine in commercial beverages.

PubMed

Rodríguez, José A; Escamilla-Lara, Karen A; Guevara-Lara, Alfredo; Miranda, Jose M; Páez-Hernández, Ma Elena

2015-01-01

A method is presented for magnetic solid phase extraction of tartrazine from nonalcoholic beverages. The method involves the extraction and clean-up by activated carbon covered with magnetite dispersed in the sample, followed by the magnetic isolation and desorption of the analyte by basified methanol. The tartrazine eluted from the magnetic support was determined by spectrophotometry. Under optimal conditions, the linear range of the calibration curve ranges from 3 to 30 mg L(-1), with a limit of detection of 1 mg L(-1). The method was validated by comparing the results with those obtained by HPLC. A precision of <5.0% was obtained in all cases and no significant differences were observed (P < 0.05).

Application of an Activated Carbon-Based Support for Magnetic Solid Phase Extraction Followed by Spectrophotometric Determination of Tartrazine in Commercial Beverages

PubMed Central

Rodríguez, José A.; Escamilla-Lara, Karen A.; Guevara-Lara, Alfredo; Miranda, Jose M.

2015-01-01

A method is presented for magnetic solid phase extraction of tartrazine from nonalcoholic beverages. The method involves the extraction and clean-up by activated carbon covered with magnetite dispersed in the sample, followed by the magnetic isolation and desorption of the analyte by basified methanol. The tartrazine eluted from the magnetic support was determined by spectrophotometry. Under optimal conditions, the linear range of the calibration curve ranges from 3 to 30 mg L−1, with a limit of detection of 1 mg L−1. The method was validated by comparing the results with those obtained by HPLC. A precision of <5.0% was obtained in all cases and no significant differences were observed (P < 0.05). PMID:25873965

Determination of ochratoxin A in wine by means of immunoaffinity and aminopropyl solid-phase column cleanup and fluorometric detection.

PubMed

Longobardi, Francesco; Iacovelli, Vito; Catucci, Lucia; Panzarini, Giuseppe; Pascale, Michelangelo; Visconti, Angelo; Agostiano, Angela

2013-02-27

A new analytical method for the determination of ochratoxin A (OTA) in red wine has been developed by using a double-extract cleanup and a fluorometric measurement after spectral deconvolution. Wine samples were diluted with a solution containing 1% polyethylene glycol and 5% sodium hydrogencarbonate, filtered, and purified by immunoaffinity and aminopropyl solid-phase column. OTA contents in the purified extract were determined by a spectrofluorometer (excitation wavelength, 330 nm; emission wavelength, 470 nm) after deconvolution of fluorescence spectra. Average recoveries from wine samples spiked with OTA at levels ranging from 0.5 to 3.0 ng/mL were 94.5-105.4% with relative standard deviations (RSD) of <15% (n = 4). The limit of detection (LOD) was 0.2 ng/mL, and the total time of analysis was 30 min. The developed method was tested on 18 red wine samples (naturally contaminated and spiked with OTA at levels ranging from 0.4 to 3.0 ng/mL) and compared with AOAC Official Method 2001.01, based on immunoaffinity column cleanup and HPLC with fluorescence detector. A good correlation (r(2) = 0.9765) was observed between OTA levels obtained with the two methods, highlighting the reliability of the proposed method, the main advantage of which is the simple OTA determination by a benchtop fluorometer with evident reductions of cost and time of analysis.

Planar solid phase extraction clean-up for pesticide residue analysis in tea by liquid chromatography-mass spectrometry.

PubMed

Oellig, Claudia; Schwack, Wolfgang

2012-10-19

Efficient clean-up is indispensable for preventing matrix effects in multi-residue analysis of pesticides in food by liquid and gas chromatography (LC and GC) coupled to mass spectrometry (MS). High-throughput planar solid phase extraction (HTpSPE) was recently introduced as a new clean-up concept in residue analysis of pesticides in fruit and vegetables (C. Oellig, W. Schwack, 2011 [45]). Thin-layer chromatography (TLC) was used to completely separate pesticides from matrix compounds and to focus them into a sharp zone, followed by extraction of the target zone by the TLC-MS interface. As rather challenging matrices, tea samples were chosen in this study. Besides chlorophylls and polyphenols, high amount of caffeine is co-extracted resulting in strong matrix effects both in LC-MS and GC-MS. The former HTpSPE procedure was adapted to initial extracts of green and black tea resulting in colorless extracts nearly free of matrix effects and interferences, as shown for seven chemically representative pesticides (acetamiprid, penconazole, azoxystrobin, chlorpyrifos, pirimicarb, fenarimol, and mepanipyrim). LC-MS/MS calibration curves obtained in the range of 0.002-0.5 mg/kg from matrix-matched standards and solvent standards were nearly identical and demonstrated the effectiveness of clean-up by HTpSPE. Mean recoveries determined by LC-MS/MS against solvent standards at spiking levels of 0.01 and 0.1 mg/kg ranged between 72 and 114% with relative standard deviations (RSDs) of 0.7-4.7% (n=4), while LC-MS measurements of tea samples spiked at 1 mg/kg provided recoveries of 81-104% with RSDs of 1.2-4.9% (n=6). Using LC-MS/MS, the method showed high sensitivity with signal-to-noise ratios>10 for concentrations below 0.002 mg/kg. HTpSPE of one sample was done in a few minutes, while numerous samples were cleaned in parallel at minimal costs with very low sample and solvent consumption. Copyright © 2012 Elsevier B.V. All rights reserved.

Liquid chromatographic determination of benzocaine and N-acetylbenzocaine in the edible fillet tissue from rainbow trout

USGS Publications Warehouse

Meinertz, J.R.; Stehly, G.R.; Hubert, T.D.; Bernardy, J.A.

1999-01-01

A method was developed for determining benzocaine and N-acetylbenzocaine concentrations in fillet tissue of rainbow trout. The method involves extracting the analytes with acetonitrile, removing lipids or hydrophobic compounds from the extract with hexane, and providing additional clean-up with solid-phase extraction techniques. Analyte concentrations are determined using reversed-phase high-performance liquid chromatographic techniques with an isocratic mobile phase and UV detection. The accuracy (range, 92 to 121%), precision (R.S.D., <14%), and sensitivity (method quantitation limit, <24 ng/g) for each analyte indicate the usefulness of this method for studies characterizing the depletion of benzocaine residues from fish exposed to benzocaine. Copyright (C) 1999.

[Determination of alkylphenol and alkylphenolpolyethoxylates in brine by solid phase extraction and high performance liquid chromatography-mass spectrometry].

PubMed

Wang, Jincheng; Xiong, Li; Zhang, Haijun; Chen, Jiping

2011-12-01

A simple method based on solid phase extraction (SPE) coupled with high performance liquid chromatography-mass spectrometry (HPLC-MS) was developed for the determination of octylphenol (OP), nonylphenol (NP), octylphenol ethoxylates (OPEOs) and nonylphenol ethoxylates (NPEOs) in brine. The extraction and cleanup of brine samples were performed on C18 solid-phase extraction cartridges. The complete separation among OP, NP, OPEOs and NPEOs was achieved on a Hypersil GOLD analytical column with methanol-water as the mobile phase. The determination was achieved using HPLC-MS with electrospray ionization (ESI) in selected ion monitoring mode. The results showed that the average recoveries of target compounds were 59.6% - 104.4% and the corresponding relative standard deviations (RSDs, n = 3) were 1.0% - 13.5%. The instrumental limits of detection for the compounds were 0.08 - 3 microg/L. This method was applied to the analysis of the samples of seawater near Dalian coast. The results showed that both NP and NPEOs were detected in all samples and their concentrations in seaport and oil port were much higher than those in other sampling sites.

Improved method for the on-line metal chelate affinity chromatography-high-performance liquid chromatographic determination of tetracycline antibiotics in animal products.

PubMed

Cooper, A D; Stubbings, G W; Kelly, M; Tarbin, J A; Farrington, W H; Shearer, G

1998-07-03

An improved on-line metal chelate affinity chromatography-high-performance liquid chromatography (MCAC-HPLC) method for the determination of tetracycline antibiotics in animal tissues and egg has been developed. Extraction was carried out with ethyl acetate. The extract was then evaporated to dryness and reconstituted in methanol prior to on-line MCAC clean-up and HPLC-UV determination. Recoveries of tetracycline, oxytetracycline, demeclocycline and chlortetracycline in the range 42% to 101% were obtained from egg, poultry, fish and venison tissues spiked at 25 micrograms kg-1. Limits of detection less than 10 microgram kg-1 were estimated for all four analytes. This method has higher throughput, higher recovery and lower limits of detection than a previously reported on-line MCAC-HPLC method which involved aqueous extraction and solid-phase extraction clean-up.

Solid-phase extraction of acidic herbicides.

PubMed

Wells, M J; Yu, L Z

2000-07-14

A discussion of solid-phase extraction method development for acidic herbicides is presented that reviews sample matrix modification, extraction sorbent selection, derivatization procedures for gas chromatographic analysis, and clean-up procedures for high-performance liquid chromatographic analysis. Acidic herbicides are families of compounds that include derivatives of phenol (dinoseb, dinoterb and pentachlorophenol), benzoic acid (acifluorfen, chloramben, dicamba, 3,5-dichlorobenzoic acid and dacthal--a dibenzoic acid derivative), acetic acid [2,4-dichlorophenoxyacetic acid (2,4-D), 4-chloro-2-methylphenoxyacetic acid (MCPA) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T)], propanoic acid [dichlorprop, fluazifop, haloxyfop, 2-(4-chloro-2-methylphenoxy)propanoic acid (MCPP) and silvex], butanoic acid [4-(2,4-dichlorophenoxy)butanoic acid (2,4-DB) and 4-(4-chloro-2-methylphenoxy)butanoic acid (MCPB)], and other miscellaneous acids such as pyridinecarboxylic acid (picloram) and thiadiazine dioxide (bentazon).

The use of coenzyme Q0 as a template in the development of a molecularly imprinted polymer for the selective recognition of coenzyme Q10.

PubMed

Contin, Mario; Flor, Sabrina; Martinefski, Manuela; Lucangioli, Silvia; Tripodi, Valeria

2014-01-07

In this work, a novel molecularly imprinted polymer (MIP) for use as a solid phase extraction sorbent was developed for the determination of coenzyme Q10 (CoQ10) in liver extract. CoQ10 is an essential cofactor in mitochondrial oxidative phosphorylation and a powerful antioxidant agent found in low concentrations in biological samples. This fact and its high hydrophobicity make the analysis of CoQ10 technically challenging. Accordingly, a MIP was synthesised using coenzyme Q0 as the template, methacrylic acid as the functional monomer, acetonitrile as the porogen, ethylene glycol dimethacrylate as the crosslinker and benzoyl peroxide as the initiator. Various parameters affecting the polymer preparation and extraction efficiency were evaluated. Morphological characterisation of the MIP and its proper comparison with C18 as a sorbent in solid phase extraction were performed. The optimal conditions for the molecularly imprinted solid phase extraction (MISPE) consisted of 400 μL of sample mixed with 30 mg of MIP and 600 μL of water to reach the optimum solution loading. The loading was followed by a washing step consisting of 1 mL of a 1-propanol solution (1-propanol:water, 30:70,v/v) and elution with 1 mL of 1-propanol. After clean-up, the CoQ10 in the samples was analysed by high performance liquid chromatography. The extraction recoveries were higher than 73.7% with good precision (3.6-8.3%). The limits of detection and quantification were 2.4 and 7.5 μg g(-1), respectively, and a linear range between 7.5 and 150 μg g(-1) of tissue was achieved. The new MISPE procedure provided a successful clean-up for the determination of CoQ10 in a complex matrix. Copyright © 2013 Elsevier B.V. All rights reserved.

Matrix solid-phase dispersion followed by gas chromatography tandem mass spectrometry for the determination of benzotriazole UV absorbers in sediments.

PubMed

Carpinteiro, I; Abuín, B; Ramil, M; Rodríguez, I; Cela, R

2012-01-01

A cost-effective and low solvent consumption method, based on the matrix solid-phase dispersion (MSPD) technique, for the determination of six benzotriazole UV absorbers in sediments is presented. Sieved samples (0.5 g) were first mixed in a mortar with a solid sorbent and then transferred to a polypropylene syringe containing a layer of clean-up co-sorbent. Analytes were eluted with a suitable solvent and further determined by gas chromatography with tandem mass spectrometry (GC-MS/MS). Under final conditions, diatomaceous earth and silica, deactivated to 10%, were used as inert dispersant and clean-up co-sorbent, respectively. Analytes were recovered using just 5 mL of dichloromethane, and this extract was concentrated and exchanged to 1 mL of isooctane. Further removal of co-extracted sulphur was achieved adding activated copper powder to final extracts, which were stored overnight, before injection in the GC-MS/MS system. The accuracy of the method was assessed with river and marine sediment samples showing different carbon contents and spiked at different concentrations in the range from 40 to 500 ng g(-1). Recoveries varied between 78% and 110% with associated standard deviations below 14%. The limits of quantification of the method stayed between 3 and 15 ng g(-1). Levels of target compounds in sediment samples ranged from not detected up to a maximum of 56 ng g(-1) for Tinuvin 328.

Quantitation of fumonisin B1 and B2 in feed using FMOC pre-column derivatization with HPLC and fluorescence detection.

PubMed

Smith, Lori L; Francis, Kyle A; Johnson, Joseph T; Gaskill, Cynthia L

2017-11-01

Pre-column derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl) was determined to be effective for quantitation of fumonisins B 1 and B 2 in feed. Liquid-solid extraction, clean-up using immunoaffinity solid phase extraction chromatography, and FMOC-derivatization preceded analysis by reverse phase HPLC with fluorescence. Instrument response was unchanged in the presence of matrix, indicating no need to use matrix-matched calibrants. Furthermore, high method recoveries indicated calibrants do not need to undergo clean-up to account for analyte loss. Established method features include linear instrument response from 0.04-2.5µg/mL and stable derivatized calibrants over 7days. Fortified cornmeal method recoveries from 0.1-30.0μg/g were determined for FB 1 (75.1%-109%) and FB 2 (96.0%-115.2%). Inter-assay precision ranged from 1.0%-16.7%. Method accuracy was further confirmed using certified reference material. Inter-laboratory comparison with naturally-contaminated field corn demonstrated equivalent results with conventional derivatization. These results indicate FMOC derivatization is a suitable alternative for fumonisins B 1 and B 2 quantitation in corn-based feeds. Copyright © 2017 Elsevier Ltd. All rights reserved.

A fully automated method for simultaneous determination of aflatoxins and ochratoxin A in dried fruits by pressurized liquid extraction and online solid-phase extraction cleanup coupled to ultra-high-pressure liquid chromatography-tandem mass spectrometry.

PubMed

Campone, Luca; Piccinelli, Anna Lisa; Celano, Rita; Russo, Mariateresa; Valdés, Alberto; Ibáñez, Clara; Rastrelli, Luca

2015-04-01

According to current demands and future perspectives in food safety, this study reports a fast and fully automated analytical method for the simultaneous analysis of the mycotoxins with high toxicity and wide spread, aflatoxins (AFs) and ochratoxin A (OTA) in dried fruits, a high-risk foodstuff. The method is based on pressurized liquid extraction (PLE), with aqueous methanol (30%) at 110 °C, of the slurried dried fruit and online solid-phase extraction (online SPE) cleanup of the PLE extracts with a C18 cartridge. The purified sample was directly analysed by ultra-high-pressure liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) for sensitive and selective determination of AFs and OTA. The proposed analytical procedure was validated for different dried fruits (vine fruit, fig and apricot), providing method detection and quantification limits much lower than the AFs and OTA maximum levels imposed by EU regulation in dried fruit for direct human consumption. Also, recoveries (83-103%) and repeatability (RSD < 8, n = 3) meet the performance criteria required by EU regulation for the determination of the levels of mycotoxins in foodstuffs. The main advantage of the proposed method is full automation of the whole analytical procedure that reduces the time and cost of the analysis, sample manipulation and solvent consumption, enabling high-throughput analysis and highly accurate and precise results.

A validated method for rapid determination of dibenzo-p-dioxins/furans (PCDD/Fs), polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in human milk: focus on utility of tandem solid phase extraction (SPE) cleanup.

PubMed

Lin, Yuanjie; Feng, Chao; Xu, Qian; Lu, Dasheng; Qiu, Xinlei; Jin, Yu'e; Wang, Guoquan; Wang, Dongli; She, Jianwen; Zhou, Zhijun

2016-07-01

An improved method based on tandem solid phase extraction (SPE) cleanup and gas chromatography-high resolution mass spectrometry (GC-HRMS) has been validated for a rapid determination of dibenzo-p-dioxins/furans (PCDD/Fs), dioxin-like polychlorinated biphenyls (PCBs), marker polychlorinated biphenyls (M-PCBs), and polybrominated diphenyl ethers (PBDEs) using a large volume (50 mL) of human milk. This method was well validated for the measurement of these analytes in human milk from the general population with low limits of detection (LODs, 0.004-0.12 ng/g lipid), satisfactory accuracy (75-120 % of recoveries), and precision [less than 10 % of relative standard deviations (RSDs)]. To comprehensively evaluate the performance of this method, a good, presently validated and routinely used method based on an automated sample clean-up system (ASCS, based on the commercial acid multilayer silica, basic alumina, and carbon columns) was used in parallel for comparison. Compared with the ASCS method, this method presented comparable specificity. Additionally, this method, in contrast to ASCS method, highly reduced consumption of solvents (40 mL versus 500 mL), which results in much lower background in the procedural blank, reduced time, and enhanced sample pretreatment throughput. This method was also applied in a pilot study to measure a batch of human milk samples with satisfactory results. Graphical Abstract Characteristics of the application of tandem SPE cleanup for determination of PCDD/Fs, DL-PCBs,M-PCBs and PBDEs in human milk.

Application of a thiourea-containing task-specific ionic liquid for the solid-phase extraction cleanup of lead ions from red lipstick, pine leaves, and water samples.

PubMed

Saljooqi, Asma; Shamspur, Tayebeh; Mohamadi, Maryam; Mostafavi, Ali

2014-07-01

Here, task-specific ionic liquid solid-phase extraction is proposed for the first time. In this approach, a thiourea-functionalized ionic liquid is immobilized on the solid sorbent, multiwalled carbon nanotubes. These modified nanotubes packed into a solid-phase extraction column are used for the selective extraction and preconcentration of ultra-trace amounts of lead(II) from aqueous samples prior to electrothermal atomic absorption spectroscopy determination. The thiourea functional groups act as chelating agents for lead ions retaining them and so, give the selectivity to the sorbent. Elution of the retained ions can be performed using an acidic thiourea solution. The effects of experimental parameters including pH of the aqueous solution, type and amount of eluent, and the flow rates of sample and eluent solutions on the separation efficiency are investigated. The linear dependence of absorbance of lead on its concentration in the initial solution is in the range of 0.5-40.0 ng/mL with the detection limit of 0.13 ng/mL (3(Sb)/m, n = 10). The proposed method is applicable to the analysis of red lipstick, pine leaves, and water samples for their lead contents. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quick and selective extraction of Z-ligustilide from Angelica sinensis using magnetic multiwalled carbon nanotubes.

PubMed

Zeng, Qiong; Jia, Yan-Wei; Xu, Pei-Li; Xiao, Meng-Wei; Liu, Yi-Ming; Peng, Shu-Lin; Liao, Xun

2015-12-01

A facile and highly efficient magnetic solid-phase extraction method has been developed for Z-ligustilide, the major therapeutic agent in Angelica sinensis. The solid-phase adsorbent material used was prepared by conjugating carbon nanotubes with magnetic Fe3 O4 nanoparticles via a hydrothermal reaction. The magnetic material showed a high affinity toward Z-ligustilide due to the π-π stacking interaction between the carbon nanotubes and Z-ligustilide, allowing a quick and selective exaction of Z-ligustilide from complex sample matrices. Factors influencing the magnetic solid-phase extraction such as the amount of the added adsorbent, adsorption and desorption time, and desorption solvent, were investigated. Due to its high extraction efficiency, this method was proved highly useful for sample cleanup/enrichment in quantitative high-performance liquid chromatography analysis. The proposed method had a linear calibration curve (R(2) = 0.9983) over the concentration between 4 ng/mL and 200 μg/mL Z-ligustilide. The accuracy of the method was determined by the recovery, which was from 92.07 to 104.02%, with the relative standard deviations >4.51%. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimization of matrix solid-phase dispersion for the rapid determination of salicylate and benzophenone-type UV absorbing substances in marketed fish.

PubMed

Tsai, Dung-Ying; Chen, Chien-Liang; Ding, Wang-Hsien

2014-07-01

A simple and effective method for the rapid determination of five salicylate and benzophenone-type UV absorbing substances in marketed fish is described. The method involves the use of matrix solid-phase dispersion (MSPD) prior to their determination by on-line silylation gas chromatography tandem mass spectrometry (GC-MS/MS). The parameters that affect the extraction efficiency were optimized using a Box-Behnken design method. The optimal extraction conditions involved dispersing 0.5g of freeze-dried powdered fish with 1.0g of Florisil using a mortar and pestle. This blend was then transferred to a solid-phase extraction (SPE) cartridge containing 1.0g of octadecyl bonded silica (C18), as the clean-up co-sorbent. The target analytes were then eluted with 7mL of acetonitrile. The extract was derivatized on-line in the GC injection-port by reaction with a trimethylsilylating (TMS) reagent. The TMS-derivatives were then identified and quantitated by GC-MS/MS. The limits of quantitation (LOQs) were less than 0.1ng/g. Copyright © 2014 Elsevier Ltd. All rights reserved.

Measurement of fumonisins in corn with a fiber optic fluoroimmunosensor

NASA Astrophysics Data System (ADS)

Thompson, Vicki S.; Maragos, Chris M.

1997-05-01

A fiber-optic immunosensor was used to determine concentrations of the mycotoxin fumonisin B1(FB1) in both spiked and naturally contaminated corn samples. Samples were extracted with a mixture of methanol/water. Two methods were used to prepare the methanolic corn extracts before introduction to the immunosensor: (1) simple dilution of the methanolic corn extract; or (2) affinity column cleanup. The sensor displayed an IC50 of 70 ng FB1/mL when toxin was introduced in phosphate buffered saline. Simple dilution of methanolic corn extracts yielded an assay with an IC50 equivalent to 25 (mu) gFB1/g corn and a limit of detection of 3.2 (mu) g/g corn, while affinity cleanup of corn extracts yielded an assay with an IC50 of 5 (mu) gFB1/g corn and a limit of detection of 0.4 (mu) gFB1/g corn. The difference in sensitivity between the two cleanup techniques was due to concentration of fumonisins obtained from the affinity cleanup procedure. Naturally contaminated corn samples were also analyzed after either simple dilution or affinity column cleanup. For comparison the naturally contaminated corn samples were analyzed with an HPLC method after isolation of the fumonisins with strong anion exchange (SAX) solid phase extraction cartridges. The SAX/HPLC method and the immunosensor method agreed well except when large amounts of other fumonisins (i.e. fumonisin B2) were present. This was due in part to the cross-reactivity of the monoclonal antibody with other fumonisins. The immunosensor has the potential to screen individual corn samples for fumonisins within six minutes, and is among the fastest of the currently available FB1 detection methods.

[Analysis of sulfonamide residues in pork and chicken by high performance liquid chromatography coupled with solid-phase extraction using multiwalled carbon nanotubes as adsorbent].

PubMed

Zhao, Haixiang; Liu, Haiping; Yan, Zaoying

2014-03-01

A multi-residue analytical method based on solid-phase extraction (SPE) with multiwalled carbon nanotubes (MWCNTs) as sorbent was developed. The determination of the sulfonamides (SAs) in pork and chicken was carried out by high performance liquid chromatography-ultraviolet detection (HPLC-UV). The clean-up conditions were optimized. The analytes were extracted by acetonitril and cleaned-up by MWCNTs SPE cartridge. The extract was redissolved with the Na2HPO4 buffer (pH 5.5-6.0) for loading, and was washed with acetone-hexane (5:95, v/v), then eluted with acetone-dichloromethane (1:1, v/v) from the column. The mobile phase used in the chromatographic separation consisted of a binary mixture of acetonitrile and 50 mmol/L NaH2PO4 with the volume ratio of 7:3. A wide linear range was 0.01-1.00 mg/L with the correlation coefficients above 0.998. The limits of detection (S/N = 3) were 0.003 mg/L, and the limits of quantification (S/N = 10) were 0.01 mg/L. The average recoveries were over 70% for the nine SAs in the spiked range of 0.02-0.2 mg/kg, with the relative standard deviations (RSDs) lower than 8%. This study indicated that the MWCNTs SPE cartridge is efficient for the clean-up of the SAs in animal tissues or products, and the method is simple, accurate and suitable for the quantification of the SAs residues.

Pesticide analysis in coffee leaves using a quick, easy, cheap, effective, rugged and safe approach and liquid chromatography tandem mass spectrometry: Optimization of the clean-up step.

PubMed

Trevisan, Maria Teresa Salles; Owen, Robert Wyn; Calatayud-Vernich, Pau; Breuer, Andrea; Picó, Yolanda

2017-08-25

An analytical method using a quick, easy, cheap, effective, rugged and safe (QuEChERS) procedure for multi-residue determination of 52 pesticides in coffee leaf extractshas been developed and validated according to SANTE/11945/2015 guidelines. Different sorbent combinations for dispersive solid phase extraction (d-SPE) clean-up as well as dispersive liquid-liquid microextraction (DLLME) were tested. The relative standard deviations (RSDs) for the recovery of 87-94% of pesticides added to coffee leaf extracts,was ≤20% for samples spiked at concentrations up to 50ng*g -1 depending on the clean-up procedures. However, samples spiked with a 100ng*g -1 pesticide mixture gave RSDs>20% for most pesticides when d-SPE was carried out adding Supelclean ENVI-Carb 120/400. To explain this fact,the secondary metabolic profile was analyzed in all the extraction and clean-up procedures. Only in the clean-up procedure with the addition of Supel QuE Z-Sep+, does caffeine show a constant adsorption between blank and spiked samples. In other clean-up procedures, the amount of caffeine was higher in those samples spiked with pesticides. This indicates competition between caffeine and pesticides for adsorption to the sorbent. Addition of Supel QuE Z-Sep+ to the procedure revealed only a 32% matrix effect, whereas using PSA+ C18 the matrix effect was close to 97%. The process efficiency is up to 54% with the addition of Supel QuE Z-Sep+ and just up to 7% for the other clean-up procedures. The method was successfully tested in coffee leaves from different types of cultivars. Pesticides were not detected in organic coffee leaf extracts, but thiametoxan was clearly detected in 50% of coffee leaf extracts harvested from coffee trees grown under traditional conditions as determined by UHPLC-TOFMSLC/QqTOF-MS/MS. Copyright © 2017 Elsevier B.V. All rights reserved.

Recent advances in analytical methods for the determination of 4-alkylphenols and bisphenol A in solid environmental matrices: A critical review.

PubMed

Salgueiro-González, N; Castiglioni, S; Zuccato, E; Turnes-Carou, I; López-Mahía, P; Muniategui-Lorenzo, S

2018-09-18

The problem of endocrine disrupting compounds (EDCs) in the environment has become a worldwide concern in recent decades. Besides their toxicological effects at low concentrations and their widespread use in industrial and household applications, these pollutants pose a risk for non-target organisms and also for public safety. Analytical methods to determine these compounds at trace levels in different matrices are urgently needed. This review critically discusses trends in analytical methods for well-known EDCs like alkylphenols and bisphenol A in solid environmental matrices, including sediment and aquatic biological samples (from 2006 to 2018). Information about extraction, clean-up and determination is covered in detail, including analytical quality parameters (QA/QC). Conventional and novel analytical techniques are compared, with their advantages and drawbacks. Ultrasound assisted extraction followed by solid phase extraction clean-up is the most widely used procedure for sediment and aquatic biological samples, although softer extraction conditions have been employed for the latter. The use of liquid chromatography followed by tandem mass spectrometry has greatly increased in the last five years. The majority of these methods have been employed for the analysis of river sediments and bivalve molluscs because of their usefulness in aquatic ecosystem (bio)monitoring programs. Green, simple, fast analytical methods are now needed to determine these compounds in complex matrices. Copyright © 2018 Elsevier B.V. All rights reserved.

Multiresidue analysis of multiclass pesticides and polyaromatic hydrocarbons in fatty fish by gas chromatography tandem mass spectrometry and evaluation of matrix effect.

PubMed

Chatterjee, Niladri S; Utture, Sagar; Banerjee, Kaushik; Ahammed Shabeer, T P; Kamble, Narayan; Mathew, Suseela; Ashok Kumar, K

2016-04-01

This paper reports a selective and sensitive method for multiresidue determination of 119 chemical residues including pesticides and polyaromatic hydrocarbons (PAH) in high fatty fish matrix. The novel sample preparation method involved extraction of the target analytes from homogenized fish meat (5 g) in acetonitrile (15 mL, 1% acetic acid) after three-phase partitioning with hexane (2 mL) and the remaining aqueous layer. An aliquot (1.5 mL) of the acetonitrile layer was aspirated and subjected to two-stage dispersive solid phase extraction (dSPE) cleanup and the residues were finally estimated by gas chromatography mass spectrometry with selected reaction monitoring (GC-MS/MS). The co-eluted matrix components were identified on the basis of their accurate mass by GC with quadrupole time of flight MS. Addition of hexane during extraction and optimized dSPE cleanup significantly minimized the matrix effects. Recoveries at 10, 25 and 50 μg/kg were within 60-120% with associated precision, RSD<11%. Copyright © 2015 Elsevier Ltd. All rights reserved.

Simple and fast analysis of tetrabromobisphenol A, hexabromocyclododecane isomers, and polybrominated diphenyl ethers in serum using solid-phase extraction or QuEChERS extraction followed by tandem mass spectrometry coupled to HPLC and GC.

PubMed

Li, Jian; Chen, Tian; Wang, Yuwei; Shi, Zhixiong; Zhou, Xianqing; Sun, Zhiwei; Wang, Dejun; Wu, Yongning

2017-02-01

Two simplified sample preparation procedures for simultaneous extraction and clean-up of tetrabromobisphenol A, α-, β-, and γ-hexabromocyclododecane and polybrominated diphenyl ethers in human serum were developed and validated. The first procedure was based on solid-phase extraction. Sample extraction, purification, and lipid removal were carried out directly on an Oasis HLB cartridge. The second procedure was a quick, easy, cheap, effective, rugged, and safe-based approach using octadecyl-modified silica particles as a sorbent. After sample extraction and cleanup, tetrabromobisphenol A/hexabromocyclododecane was separated from polybrominated diphenyl ethers by using a Si-based cartridge. Tetrabromobisphenol A and hexabromocyclododecane were then detected by high-performance liquid chromatography coupled to tandem mass spectrometry, while polybrominated diphenyl ethers were detected by gas chromatography coupled to tandem mass spectrometry. The results of the spike recovery test using fetal bovine serum showed that the average recoveries of the analytes ranged from 87.3 to 115.3% with relative standard deviations equal to or lower than 13.4 %. Limits of detection of the analytes were in the range of 0.4-19 pg/mL except for decabromodiphenyl ether. The developed method was successfully applied to routine analysis of human serum samples from occupational workers and the general population. Extremely high serum polybrominated diphenyl ethers levels up to 3.32 × 10 4 ng/g lipid weight were found in occupational workers. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development and validation of a solid phase extraction sample cleanup procedure for the recovery of trace levels of nitro-organic explosives in soil.

PubMed

Thomas, Jennifer L; Donnelly, Christopher C; Lloyd, Erin W; Mothershead, Robert F; Miller, Mark L

2018-03-01

An improved cleanup method has been developed for the recovery of trace levels of 12 nitro-organic explosives in soil, which is important not only for the forensic community, but also has environmental implications. A wide variety of explosives or explosive-related compounds were evaluated, including nitramines, nitrate esters, nitroaromatics, and a nitroalkane. Fortified soil samples were extracted with acetone, processed via solid phase extraction (SPE), and then analyzed by gas chromatography with electron capture detection. The following three SPE sorbents in cartridge format were compared: Empore™ SDB-XC, Oasis ® HLB, and Bond Elut NEXUS cartridges. The NEXUS cartridges provided the best overall recoveries for the 12 explosives in potting soil (average 48%) and the fastest processing times (<30min). It also rejected matrix components from spent motor oil on potting soil. The SPE method was validated by assessing limit of detection (LOD), processed sample stability, and interferences. All 12 compounds were detectable at 0.02μg explosive/gram of soil or lower in the three matrices tested (potting soil, sand, and loam) over three days. Seven explosives were stable up to seven days at 2μg/g and three were stable at 0.2μg/g, both in processed loam, which was the most challenging matrix. In the interference study, five interferences above the determined LOD for soil were detected in matrices collected across the United States and in purchased all-purpose sand, potting soil, and loam. This represented a 3.2% false positive rate for the 13 matrices processed by the screening method for interferences. The reported SPE cleanup method provides a fast and simple extraction process for separating organic explosives from matrix components, facilitating sample throughput and reducing instrument maintenance. In addition, a comparison study of the validated SPE method versus conventional syringe filtration was completed and highlighted the benefits of sample cleanup for removing matrix interferences, while also providing lower supply cost, order of magnitude lower LODs for most explosives, higher percent recoveries for complex matrices, and fewer instrument maintenance issues. Published by Elsevier B.V.

Determination of six pesticides in the medicinal herb Cordia salicifolia by matrix solid-phase dispersion and gas chromatography/mass spectrometry.

PubMed

de Carvalho, Pedro Henrique Viana; Prata, Vanessa de Menezes; Alves, Péricles Barreto; Navickiene, Sandro

2009-01-01

A simple and effective extraction method based on matrix solid-phase dispersion was developed for acephate, chlorpropham, pyrimicarb, bifenthrin, tetradifon, and phosalone in leaves of the medicinal plant Cordia salicifolia, whose extracts are commercialized in Brazil as diuretic, appetite suppressant, and weight loss products. The determination method was GC/MS with selected-ion monitoring. Different parameters of the method were evaluated, such as type of solid phase (C18, alumina, silica gel, and Florisil) and the amount of solid phase and eluent (dichloromethane, ethyl acetate, chloroform, and cyclohexane). The best results were obtained using 0.5 g herb sample, 0.5 g neutral alumina as the dispersant sorbent, 0.5 g C18 as the cleanup sorbent, and cyclohexane-dichloromethane (3 + 1, v/v) as the eluting solvent. The method was validated using herb samples fortified with pesticides at different concentration levels (0.3, 0.5, and 1.0 mg/kg). Average recoveries (seven replicates) ranged from 67.7 to 129.9%, with relative standard deviations between 6.3 and 26%. Detection and quantitation limits for the herb ranged from 0.10 to 0.15 and 0.15 to 0.25 mg/kg, respectively.

Ion-exchange solid-phase extraction combined with liquid chromatography-tandem mass spectrometry for the determination of veterinary drugs in organic fertilizers.

PubMed

Zhao, Zhiyong; Zhang, Yanmei; Xuan, Yanfang; Song, Wei; Si, Wenshuai; Zhao, Zhihui; Rao, Qinxiong

2016-06-01

The analysis of veterinary drugs in organic fertilizers is crucial for an assessment of potential risks to soil microbial communities and human health. We develop a robust and sensitive method to quantitatively determine 19 veterinary drugs (amantadine, sulfonamides and fluoroquinolones) in organic fertilizers. The method involved a simple solid-liquid extraction step using the combination of acetonitrile and McIlvaine buffer as extraction solvent, followed by cleanup with a solid-phase extraction cartridge containing polymeric mixed-mode anion-exchange sorbents. Ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was used to separate and detect target analytes. We particularly focused on the optimization of sample clean-up step: different diluents and dilution factors were tested. The developed method was validated in terms of linearity, recovery, precision, sensitivity and specificity. The recoveries of all the drugs ranged from 70.9% to 112.7% at three concentration levels, with the intra-day and inter-day relative standard deviation lower than 15.7%. The limits of quantification were between 1.0 and 10.0μg/kg for all the drugs. Matrix effect was minimized by matrix-matched calibration curves. The analytical method was successfully applied for the survey of veterinary drugs contamination in 20 compost samples. The results indicated that fluoroquinolones had higher incidence rate and mean concentration levels ranging from 31.9 to 308.7μg/kg compared with other drugs. We expect the method will provide the basis for risk assessment of veterinary drugs in organic fertilizers. Copyright © 2016 Elsevier B.V. All rights reserved.

Determination of perfluorinated compounds in mollusks by matrix solid-phase dispersion and liquid chromatography-tandem mass spectrometry.

PubMed

Villaverde-de-Sáa, Eugenia; Quintana, José Benito; Rodil, Rosario; Ferrero-Refojos, Raúl; Rubí, Elisa; Cela, Rafael

2012-01-01

Perfluorinated compounds (PFCs) have been used for over 40 years in different commercial and industrial applications mainly as surfactants and surface protectors and have become an important class of marine emerging pollutants. This study presents the development and validation of a new analytical method to determine the simultaneous presence of eight PFCs in different kinds of mollusks using matrix solid-phase dispersion (MSPD) followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Simplicity of the analytical procedure, low volume of solvent and quantity of sample required, low global price, and integration of extraction and clean-up into a single step, are the most important advantages of the developed methodology. Solvent, solid support (dispersing agent), clean-up sorbent, and their amounts were optimized by means of an experimental design. In the final method, 0.5 g of sample are dispersed with 0.2 g of diatomaceous earth and transferred into a polypropylene syringe containing 4 g of silica as clean-up sorbent. Then, analytes are eluted with 20 mL of acetonitrile. The extract is finally concentrated to a final volume of 0.5 mL in methanol, avoiding extract dryness in order to prevent evaporation losses and injected in the LC-MS/MS. The combination of this MSPD protocol with LC-MS/MS afforded detection limits from 0.05 to 0.3 ng g(-1). Also, a good linearity was established for the eight PFCs in the range from limit of quantification (LOQ) to 500 ng mL(-1) with R(2) > 0.9917. The recovery of the method was studied with three types of spiked mollusk and was in the 64-126% range. Moreover, a mussel sample was spiked and aged for more than 1 month and analyzed by the developed method and a reference method, ion-pair extraction, for comparison, producing both methods statistically equal concentration values. The method was finally applied to the determination of PFCs in different kinds of mollusks revealing concentrations up to 8.3 ng g(-1) for perfluoroundecanoic acid.

Molecularly imprinted solid-phase extraction for the selective determination of bromhexine in human serum and urine with high performance liquid chromatography.

PubMed

Javanbakht, Mehran; Namjumanesh, Mohammad Hadi; Akbari-Adergani, Behrouz

2009-11-15

In this work, a novel method is described for the determination of bromhexine in biological fluids using molecularly imprinted solid-phase extraction as the sample cleanup technique combined with high performance liquid chromatography (HPLC). The water-compatible molecularly imprinted polymers (MIPs) were prepared using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linker, chloroform as porogen and bromhexine as the template molecule. The novel imprinted polymer was used as a solid-phase extraction sorbent for the extraction of bromhexine from human serum and urine. Various parameters affecting the extraction efficiency of the polymer have been evaluated. The optimal conditions for molecularly imprinted solid-phase extraction (MISPE) consisted of conditioning 1 mL methanol and 1 mL of deionized water at neutral pH, loading of 5 mL of the water sample (25 microg L(-1)) at pH 6.0, washing using 2 mL acetonitrile/acetone (1/4, v/v) and elution with 3x 1 mL methanol/acetic acid (10/1, v/v). The MIP selectivity was evaluated by checking several substances with similar molecular structures to that of bromhexine. Results from the HPLC analyses showed that the calibration curve of bromhexine using MIP from human serum and urine is linear in the ranges of 0.5-100 and 1.5-100 microg L(-1) with good precisions (3.3% and 2.8% for 5.0 microg L(-1)), respectively. The recoveries for serum and urine samples were higher than 92%.

Graphene oxide-based dispersive solid-phase extraction combined with in situ derivatization and gas chromatography-mass spectrometry for the determination of acidic pharmaceuticals in water.

PubMed

Naing, Nyi Nyi; Li, Sam Fong Yau; Lee, Hian Kee

2015-12-24

A fast and low-cost sample preparation method of graphene based dispersive solid-phase extraction combined with gas chromatography-mass spectrometric (GC-MS) analysis, was developed. The procedure involves an initial extraction with water-immiscible organic solvent, followed by a rapid clean-up using amine functionalized reduced graphene oxide as sorbent. Simple and fast one-step in situ derivatization using trimethylphenylammonium hydroxide was subsequently applied on acidic pharmaceuticals serving as model analytes, ibuprofen, gemfibrozil, naproxen, ketoprofen and diclofenac, before GC-MS analysis. Extraction parameters affecting the derivatization and extraction efficiency such as volume of derivatization agent, effect of desorption solvent, effect of pH and effect of ionic strength were investigated. Under the optimum conditions, the method demonstrated good limits of detection ranging from 1 to 16ngL(-1), linearity (from 0.01 to 50 and 0.05 to 50μgL(-1), depending on the analytes) and satisfactory repeatability of extractions (relative standard deviations, below 13%, n=3). Copyright © 2015 Elsevier B.V. All rights reserved.

Solid-Phase Extraction (SPE): Principles and Applications in Food Samples.

PubMed

Ötles, Semih; Kartal, Canan

2016-01-01

Solid-Phase Extraction (SPE) is a sample preparation method that is practised on numerous application fields due to its many advantages compared to other traditional methods. SPE was invented as an alternative to liquid/liquid extraction and eliminated multiple disadvantages, such as usage of large amount of solvent, extended operation time/procedure steps, potential sources of error, and high cost. Moreover, SPE can be plied to the samples combined with other analytical methods and sample preparation techniques optionally. SPE technique is a useful tool for many purposes through its versatility. Isolation, concentration, purification and clean-up are the main approaches in the practices of this method. Food structures represent a complicated matrix and can be formed into different physical stages, such as solid, viscous or liquid. Therefore, sample preparation step particularly has an important role for the determination of specific compounds in foods. SPE offers many opportunities not only for analysis of a large diversity of food samples but also for optimization and advances. This review aims to provide a comprehensive overview on basic principles of SPE and its applications for many analytes in food matrix.

Application of the powder of porous titanium carbide ceramics to a reusable adsorbent for environmental pollutants.

PubMed

Moriwaki, Hiroshi; Kitajima, Shiori; Shirai, Koji; Kiguchi, Kenji; Yamada, Osamu

2011-01-30

The aim of this study is to investigate the utilization of the powder of porous titanium carbide (TiC) ceramics as a novel adsorbent or a material for solid-phase extraction (SPE). The adsorption and elution of inorganic and organic pollutants, Pb(II), 2,4,6-trichlorophenol (TCP), perfluorooctane sulfonate (PFOS), and perfluorooctanoic acid (PFOA), to the material were evaluated. The cartridge packed with TiC ceramics powder was used for the extraction test of pollutants. The solution containing pollutants at 1.0 μg mL(-1) was passed through the TiC cartridge, and the substances were almost quantitatively removed. Furthermore, the pollutants retained in the cartridge were eluted with 3N HCl for Pb(II) and with methanol for organic pollutants. The recoveries of pollutants were over 80%. In addition, we used the TiC cartridge for the solid-phase extraction of water samples (500 mL each of the distilled water and the river water) by adding pollutants at determined concentrations. Every pollutant was adsorbed almost quantitatively, and eluted by 3N HCl or methanol. From these results, we concluded that the powder of porous TiC ceramics is a useful reusable adsorbent for the water cleanup and solid-phase extraction. Copyright © 2010 Elsevier B.V. All rights reserved.

Determination of triazine herbicides in seaweeds: development of a sample preparation method based on Matrix Solid Phase Dispersion and Solid Phase Extraction Clean-up.

PubMed

Rodríguez-González, N; González-Castro, M J; Beceiro-González, E; Muniategui-Lorenzo, S; Prada-Rodríguez, D

2014-04-01

A method using dual process columns of Matrix Solid Phase Dispersion (MSPD) and Solid Phase Extraction (SPE) has been developed for extracting and cleaning-up of nine triazine herbicides (ametryn, atrazine, cyanazine, prometryn, propazine, simazine, simetryn, terbuthylazine and terbutryn) in seaweed samples. Under optimized conditions, samples were blended with 2g of octasilyl-derivatized silica (C8) and transferred into an SPE cartridge containing ENVI-Carb II/PSA (0.5/0.5 g) as a clean up co-sorbent. Then the dispersed sample was washed with 10 mL of n-hexane and triazines were eluted with 20 mL ethyl acetate and 5 mL acetonitrile. Finally the extract was concentrated to dryness, re-constituted with 1 mL methanol:water (1:1) and injected into the HPLC-DAD system. The linearity of the calibration curves was excellent in matrix matched standards, and yielded the coefficients of determination>0.995 for all the target analytes. The recoveries ranged from 75% to 100% with relative standard deviations lower than 7%. The achieved LOQs (<10 µg kg(-1)) for all triazines under study permits to ensure proper determination at the maximum allowed residue levels set in the European Union Legislation. Samples of three seaweeds were subjected to the procedure proving the suitability of MSPD method for the analysis of triazines in different seaweeds samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Separation techniques for the clean-up of radioactive mixed waste for ICP-AES/ICP-MS analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swafford, A.M.; Keller, J.M.

1993-03-17

Two separation techniques were investigated for the clean-up of typical radioactive mixed waste samples requiring elemental analysis by Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) or Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). These measurements frequently involve regulatory or compliance criteria which include the determination of elements on the EPA Target Analyte List (TAL). These samples usually consist of both an aqueous phase and a solid phase which is mostly an inorganic sludge. Frequently, samples taken from the waste tanks contain high levels of uranium and thorium which can cause spectral interferences in ICP-AES or ICP-MS analysis. The removal of these interferences ismore » necessary to determine the presence of the EPA TAL elements in the sample. Two clean-up methods were studied on simulated aqueous waste samples containing the EPA TAL elements. The first method studied was a classical procedure based upon liquid-liquid extraction using tri-n- octylphosphine oxide (TOPO) dissolved in cyclohexane. The second method investigated was based on more recently developed techniques using extraction chromatography; specifically the use of a commercially available Eichrom TRU[center dot]Spec[trademark] column. Literature on these two methods indicates the efficient removal of uranium and thorium from properly prepared samples and provides considerable qualitative information on the extraction behavior of many other elements. However, there is a lack of quantitative data on the extraction behavior of elements on the EPA Target Analyte List. Experimental studies on these two methods consisted of determining whether any of the analytes were extracted by these methods and the recoveries obtained. Both methods produced similar results; the EPA target analytes were only slightly or not extracted. Advantages and disadvantages of each method were evaluated and found to be comparable.« less

Simultaneous multi-mycotoxin determination in nutmeg by ultrasound-assisted solid-liquid extraction and immunoaffinity column clean-up coupled with liquid chromatography and on-line post-column photochemical derivatization-fluorescence detection.

PubMed

Kong, Wei-Jun; Liu, Shu-Yu; Qiu, Feng; Xiao, Xiao-He; Yang, Mei-Hua

2013-05-07

A simple and sensitive analytical method based on ultrasound-assisted solid-liquid extraction and immunoaffinity column clean-up coupled with high performance liquid chromatography and on-line post-column photochemical derivatization-fluorescence detection (USLE-IAC-HPLC-PCD-FLD) has been developed for simultaneous multi-mycotoxin determination of aflatoxins B1, B2, G1, G2 (AFB1, AFB2, AFG1, AFG2) and ochratoxin A (OTA) in 13 edible and medicinal nutmeg samples marketed in China. AFs and OTA were extracted from nutmeg samples by ultrasonication using a methanol : water (80 : 20, v/v) solution, followed by an IAC clean-up step. Different USL extraction conditions, pre-processing ways for nutmeg sample and clean-up columns for mycotoxins, as well as HPLC-PCD-FLD parameters (mobile phase, column temperature, elution procedure, excitation and emission wavelengths) were optimized. This method, which was appraised for analyzing nutmeg samples, showed satisfactory results with reference to limits of detection (LODs) (from 0.02 to 0.25 μg kg(-1)), limits of quantification (LOQs) (from 0.06 to 0.8 μg kg(-1)), linear ranges (up to 30 ng mL(-1) for AFB1, AFG1 and OTA and 9 ng mL(-1) for AFB2 and AFG2), intra- and inter-day variability (all <2%) and average recoveries (from 79.6 to 90.8% for AFs and from 93.6 to 97.3% for OTA, respectively). The results of the application of developed method in nutmeg samples have elucidated that four samples were detected with contamination of AFs and one with OTA. AFB1 was the most frequently found mycotoxin in 30.8% of nutmeg samples at contamination levels of 0.73-16.31 μg kg(-1). At least two different mycotoxins were co-occurred in three samples, and three AFs were simultaneously detected in one sample.

Simultaneous determination of multiresidual phenyl acetanilide pesticides in different food commodities by solid-phase cleanup and gas chromatography-mass spectrometry.

PubMed

Li, Yongjun; Wang, Meiling; Yan, Hongfei; Fu, Shanliang; Dai, Hua

2013-03-01

An efficient and sensitive multiresidue method has been developed for quantification and confirmation of 25 phenyl acetanilide pesticides in a wide variety of food commodities including maize, spinach, mushroom, apple, soybean, chestnut, tea, beef, cattle liver, chicken, fish, and milk. Analytes were extracted with acetone-n-hexane (1:2, v/v) followed by cleanup using SPE. Several types of adsorbents were evaluated. Neutral aluminum and graphitized carbon black cartridge showed good cleanup efficiency. The extract was determined by GC-MS in the selected ion monitoring mode using one target and two qualitative ions for each analyte. The limits of detection were 0.01 mg/kg for all analytes. The average recoveries ranged from 66.9 to 110.6% (mean 88.8%) and RSDs were in the range 2.0-19% (mean 10.5%) across three fortification levels. The proposed method was successfully applied to real samples in routine analysis and a satisfactory result was obtained. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparison of Clean-Up Methods for Ochratoxin A on Wine, Beer, Roasted Coffee and Chili Commercialized in Italy

PubMed Central

Prelle, Ambra; Spadaro, Davide; Denca, Aleksandra; Garibaldi, Angelo; Gullino, Maria Lodovica

2013-01-01

The most common technique used to detect ochratoxin A (OTA) in food matrices is based on extraction, clean-up, and chromatography detection. Different clean-up cartridges, such as immunoaffinity columns (IAC), molecular imprinting polymers (MIP), Mycosep™ 229, Mycospin™, and Oasis® HLB (Hydrophilic Lipophilic balance) as solid phase extraction were tested to optimize the purification for red wine, beer, roasted coffee and chili. Recovery, reproducibility, reproducibility, limit of detection (LOD) and limit of quantification (LOQ) were calculated for each clean-up method. IAC demonstrated to be suitable for OTA analysis in wine and beer with recovery rate >90%, as well as Mycosep™ for wine and chili. On the contrary, MIP columns were the most appropriate to clean up coffee. A total of 120 samples (30 wines, 30 beers, 30 roasted coffee, 30 chili) marketed in Italy were analyzed, by applying the developed clean-up methods. Twenty-seven out of 120 samples analyzed (22.7%: two wines, five beers, eight coffees, and 12 chili) resulted positive to OTA. A higher incidence of OTA was found in chili (40.0%) more than wine (6.6%), beers (16.6%) and coffee (26.6%). Moreover, OTA concentration in chili was the highest detected, reaching 47.8 µg/kg. Furthermore, three samples (2.5%), two wines and one chili, exceeded the European threshold. PMID:24152987

[Determination of emamectin benzoate residue in vegetables by high performance liquid chromatography with fluorescence detection].

PubMed

Zhang, Yan; Wu, Yinliang; Hu, Jiye; Wang, Hongwei; Pan, Canping; Liu, Fengmao

2008-01-01

A method was developed for the determination of emamectin benzoate residue in cabbage and mushroom using solid-phase extraction (SPE) and high performance liquid chromatography (HPLC) with fluorescence detection. The sample was extracted with ethyl acetate. Further cleanup was performed on a propylsulfonic acid solid phase extraction cartridge, followed by the derivatization with trifluoroacetic anhydride in the presence of N-methylimidazole. The amount of derivatized emamectin benzoate was determined by fluorescence detector after separation by HPLC. The detection limit was 0.10 microg/kg for cabbage and mushroom samples. The recoveries of emamectin benzoate in cabbage and mushroom samples were 78.6%-84.9%. The inter-day relative standard deviation (RSD) and intra-day RSD were 2.7%-6.0% and 3.1%-8.9%, respectively, at the fortified levels of 1.0-20.0 microg/kg. The calibration curve of emamectin benzoate in vegetables at the concentration range of 0.002 mg/L to 0.10 mg/L was linear (r = 0.9999).

Rapid preconcentration method for the determination of azadirachtin-A and -B, nimbin and salannin in neem oil samples by using graphitised carbon solid phase extraction.

PubMed

Ramesh, A; Balasubramanian, M

1999-01-01

A simple and rapid method involving solid phase extraction and liquid chromatography for the determination of azadirachtin-A and -B, nimbin and salannin at nanogram levels in neem oil samples is presented. The neem oil samples are defatted and the compounds of interest extracted by mixing the sample with hexane and passing the hexane solution through a graphitised carbon black column. After washing the column with 2 ml of hexane, azadirachtin-A and -B, nimbin and salannin are eluted with 5 ml of acetonitrile and quantified using HPLC with UV detection. The recoveries of azadirachtin-A and -B, nimbin and salannin in fortified oil samples were 97.4-104.7%. The upper limit of quantification is up to 100 micrograms ml-1 without any additional clean-up and with little interference from lipids during the analysis by HPLC. The method was successfully applied to various neem oil samples collected from different locations in India.

Micro-solid-phase extraction (µ-SPE) of organophosphorous pesticides from wheat followed by LC-MS/MS determination.

PubMed

Della Pelle, Flavio; Di Crescenzo, Maria Chiara; Sergi, Manuel; Montesano, Camilla; Di Ottavio, Francesca; Scarpone, Rossana; Scortichini, Giampiero; Compagnone, Dario

2016-01-01

A rapid, selective and effective method of extraction, clean-up and concentration of organophosphorous pesticides from wheat followed by electrospray (ESI) LC-MS/MS analysis was developed. The μ-SPE (micro-solid-phase extraction) procedure resulted in good analytical performance and reduced at the same time matrix effects, analysis time and solvent consumption. Limits of detection (LODs) and quantification (LOQs) were in the range of 0.3-10 and 1-30 μg kg(-1), respectively, with good reproducibility (RSD ≤ 13.8) and recoveries between 75% and 109%. Coefficients of determination (r(2)) were greater than 0.996 for the studied pesticides. Despite the reduced sorbent bed mass of μ-SPE tips (4.2 mg), the analytical data showed that no saturation phenomena occurs in the tested range of concentration both for single compounds and mixtures. Several real samples were analysed and the concentrations of the selected pesticides were found to be below the respective maximum residue limit (MRLs).

Dispersive solid-phase extraction followed by vortex-assisted dispersive liquid-liquid microextraction based on the solidification of a floating organic droplet for the determination of benzoylurea insecticides in soil and sewage sludge.

PubMed

Peng, Guilong; He, Qiang; Mmereki, Daniel; Lu, Ying; Zhong, Zhihui; Liu, Hanyang; Pan, Weiliang; Zhou, Guangming; Chen, Junhua

2016-04-01

A novel dispersive solid-phase extraction combined with vortex-assisted dispersive liquid-liquid microextraction based on solidification of floating organic droplet was developed for the determination of eight benzoylurea insecticides in soil and sewage sludge samples before high-performance liquid chromatography with ultraviolet detection. The analytes were first extracted from the soil and sludge samples into acetone under optimized pretreatment conditions. Clean-up of the extract was conducted by dispersive solid-phase extraction using activated carbon as the sorbent. The vortex-assisted dispersive liquid-liquid microextraction based on solidification of floating organic droplet procedure was performed by using 1-undecanol with lower density than water as the extraction solvent, and the acetone contained in the solution also acted as dispersive solvent. Under the optimum conditions, the linearity of the method was in the range 2-500 ng/g with correlation coefficients (r) of 0.9993-0.9999. The limits of detection were in the range of 0.08-0.56 ng/g. The relative standard deviations varied from 2.16 to 6.26% (n = 5). The enrichment factors ranged from 104 to 118. The extraction recoveries ranged from 81.05 to 97.82% for all of the analytes. The good performance has demonstrated that the proposed methodology has a strong potential for application in the multiresidue analysis of complex matrices. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development and validation of a solid-phase extraction method coupled to liquid chromatography with fluorescence detection for the determination of fluoroquinolone residues in powdered infant formulae. Application to the analysis of samples from the Spanish and Latin American market.

PubMed

Rodriguez, E; Moreno-Bondi, M C; Marazuela, M D

2008-10-31

This paper describes a new method for the effective extraction, clean-up and chromatographic analysis of residues of four fluoroquinolones (ciprofloxacin, enrofloxacin, danofloxacin and sarafloxacin) in powdered infant formulae and follow-on preparations. Samples were reconstituted following the manufacturer's recommendations and treated with trichloroacetic acid in methanol 10% (w/v) for deproteinization. Two solid-phase extraction cartridges have been evaluated for sample clean-up and preconcentration, Strata Screen A and Strata X and the later provided the best recoveries for all the analytes tested. Chromatographic analysis has been carried out using a polar endcapped column (AQUA C(18)) and fluorescence detection, with lomefloxacin (LOME) as internal standard. Method validation has been performed according to European Commission Decision 2002/657/EC criteria, in terms of linearity, recovery, precision, specificity, decision limit (CC(alpha)) and detection capability (CC(beta)). Typical recoveries ranged between 70 and 110% at levels below and above the maximum residue limits of the target analytes in bovine milk, with an excellent intralab reproducibility (RSDs<7%). Matrix effects did not significantly affect method accuracy, as evidenced by analyzing different brands of milk. The method has been successfully applied to the analysis of 100 samples of infant and follow-on formulae of the Spanish and Latin American market, using LC-MS/MS as confirmatory technique.

Determination of perfluoroalkyl carboxylic, sulfonic, and phosphonic acids in food.

PubMed

Ullah, Shahid; Alsberg, Tomas; Vestergren, Robin; Berger, Urs

2012-11-01

A sensitive and accurate method was developed and validated for simultaneous analysis of perfluoroalkyl carboxylic acids, sulfonic acids, and phosphonic acids (PFPAs) at low picograms per gram concentrations in a variety of food matrices. The method employed extraction with acetonitrile/water and cleanup on a mixed-mode co-polymeric sorbent (C8 + quaternary amine) using solid-phase extraction. High-performance liquid chromatographic separation was achieved on a C18 column using a mobile phase gradient containing 5 mM 1-methyl piperidine for optimal chromatographic resolution of PFPAs. A quadrupole time-of-flight high-resolution mass spectrometer operating in negative ion mode was used as detector. Method detection limits were in the range of 0.002 to 0.02 ng g(-1) for all analytes. Sample preparation (extraction and cleanup) recoveries at a spiking level of 0.1 ng g(-1) to a baby food composite were in the range of 59 to 98 %. A strong matrix effect was observed in the analysis of PFPAs in food extracts, which was tentatively assigned to sorption of PFPAs to the injection vial in the solvent-based calibration standard. The method was successfully applied to a range of different food matrices including duplicate diet samples, vegetables, meat, and fish samples.

Multi-class multi-residue analysis of veterinary drugs in meat using enhanced matrix removal lipid cleanup and liquid chromatography-tandem mass spectrometry.

PubMed

Zhao, Limian; Lucas, Derick; Long, David; Richter, Bruce; Stevens, Joan

2018-05-11

This study presents the development and validation of a quantitation method for the analysis of multi-class, multi-residue veterinary drugs using lipid removal cleanup cartridges, enhanced matrix removal lipid (EMR-Lipid), for different meat matrices by liquid chromatography tandem mass spectrometry detection. Meat samples were extracted using a two-step solid-liquid extraction followed by pass-through sample cleanup. The method was optimized based on the buffer and solvent composition, solvent additive additions, and EMR-Lipid cartridge cleanup. The developed method was then validated in five meat matrices, porcine muscle, bovine muscle, bovine liver, bovine kidney and chicken liver to evaluate the method performance characteristics, such as absolute recoveries and precision at three spiking levels, calibration curve linearity, limit of quantitation (LOQ) and matrix effect. The results showed that >90% of veterinary drug analytes achieved satisfactory recovery results of 60-120%. Over 97% analytes achieved excellent reproducibility results (relative standard deviation (RSD) < 20%), and the LOQs were 1-5 μg/kg in the evaluated meat matrices. The matrix co-extractive removal efficiency by weight provided by EMR-lipid cartridge cleanup was 42-58% in samples. The post column infusion study showed that the matrix ion suppression was reduced for samples with the EMR-Lipid cartridge cleanup. The reduced matrix ion suppression effect was also confirmed with <15% frequency of compounds with significant quantitative ion suppression (>30%) for all tested veterinary drugs in all of meat matrices. The results showed that the two-step solid-liquid extraction provides efficient extraction for the entire spectrum of veterinary drugs, including the difficult classes such as tetracyclines, beta-lactams etc. EMR-Lipid cartridges after extraction provided efficient sample cleanup with easy streamlined protocol and minimal impacts on analytes recovery, improving method reliability and consistency. Copyright © 2018 Elsevier B.V. All rights reserved.

A multiresidue method for the analysis of 90 pesticides, 16 PAHs, and 22 PCBs in honey using QuEChERS-SPME.

PubMed

Al-Alam, Josephine; Fajloun, Ziad; Chbani, Asma; Millet, Maurice

2017-08-01

An optimized analytical method was developed for the simultaneous analysis of 90 pesticides, 16 polycyclic aromatic hydrocarbons, and 22 polychlorinated biphenyls. The method was based on quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction using acetonitrile followed by a dispersive solid-phase extraction cleanup using primary-secondary amine and octadecyl (C 18 ). The extract obtained was concentrated by evaporation and then reconstituted with acetonitrile to prepare it for chromatographic analysis by liquid chromatography-triple-quadrupole tandem mass spectrometry and gas chromatography-ion-trap tandem mass spectrometry, which was preceded by a preconcentration step using solid-phase microextraction with appropriate fibers. The combination of the two extraction steps ensured efficient extract cleanup. The use of the two analytical instruments allowed the analysis of a large number of pollutants with a high reliability rate. The method developed was validated for linearity, which was studied with use of matrix-matched calibration curves in the concentration range between 10 and 3000 ng g -1 . The correlation coefficient (R 2 ) obtained was higher than 0.98 for most of the target compounds, with a relative standard deviation lower than 20% for repeatability and reproducibility. The limits of detection and quantification were lower than 20 and 60 ng g -1 respectively for the compounds analyzed, and the recoveries were between 60% and 103% for most compounds. Finally, the method was tested for its efficiency on real samples by the analysis of three honey samples in which seven pesticides and nine polycyclic aromatic hydrocarbons were determined. Graphical Abstract ᅟ.

Pressurized liquid extraction using water/isopropanol coupled with solid-phase extraction cleanup for semivolatile organic compounds, polycyclic aromatic hydrocarbons (PAH), and alkylated PAH homolog groups in sediment

USGS Publications Warehouse

Burkhardt, M.R.; Zaugg, S.D.; Burbank, T.L.; Olson, M.C.; Iverson, J.L.

2005-01-01

Polycyclic aromatic hydrocarbons (PAH) are recognized as environmentally relevant for their potential adverse effects on human and ecosystem health. This paper describes a method to determine the distribution of PAH and alkylated homolog groups in sediment samples. Pressurized liquid extraction (PLE), coupled with solid-phase extraction (SPE) cleanup, was developed to decrease sample preparation time, to reduce solvent consumption, and to minimize background interferences for full-scan GC-MS analysis. Recoveries from spiked Ottawa sand, environmental stream sediment, and commercially available topsoil, fortified at 1.5-15 ??g per compound, averaged 94.6 ?? 7.8%, 90.7 ?? 5.8% and 92.8 ?? 12.8%, respectively. Initial method detection limits for single-component compounds ranged from 20 to 302 ??g/kg, based on 25 g samples. Results from 28 environmental sediment samples, excluding homologs, show 35 of 41 compounds (85.4%) were detected in at least one sample with concentrations ranging from 20 to 100,000 ??g/kg. The most frequently detected compound, 2,6-dimethylnaphthalene, was detected in 23 of the 28 (82%) environmental samples with a concentration ranging from 15 to 907 ??g/kg. The results from the 28 environmental sediment samples for the homolog series showed that 27 of 28 (96%) samples had at least one homolog series present at concentrations ranging from 20 to 89,000 ??g/kg. The most frequently detected homolog series, C2-alkylated naphthalene, was detected in 26 of the 28 (93%) environmental samples with a concentration ranging from 25 to 3900 ??g/kg. Results for a standard reference material using dichloromethane Soxhlet-based extraction also are compared. ?? 2005 Elsevier B.V. All rights reserved.

High-throughput method for the determination of residues of β-lactam antibiotics in bovine milk by LC-MS/MS.

PubMed

Jank, Louise; Martins, Magda Targa; Arsand, Juliana Bazzan; Hoff, Rodrigo Barcellos; Barreto, Fabiano; Pizzolato, Tânia Mara

2015-01-01

This study describes the development and validation procedures for scope extension of a method for the determination of β-lactam antibiotic residues (ampicillin, amoxicillin, penicillin G, penicillin V, oxacillin, cloxacillin, dicloxacillin, nafcillin, ceftiofur, cefquinome, cefoperazone, cephapirine, cefalexin and cephalonium) in bovine milk. Sample preparation was performed by liquid-liquid extraction (LLE) followed by two clean-up steps, including low temperature purification (LTP) and a solid phase dispersion clean-up. Extracts were analysed using a liquid chromatography-electrospray-tandem mass spectrometry system (LC-ESI-MS/MS). Chromatographic separation was performed in a C18 column, using methanol and water (both with 0.1% of formic acid) as mobile phase. Method validation was performed according to the criteria of Commission Decision 2002/657/EC. Main validation parameters such as linearity, limit of detection, decision limit (CCα), detection capability (CCβ), accuracy, and repeatability were determined and were shown to be adequate. The method was applied to real samples (more than 250) and two milk samples had levels above maximum residues limits (MRLs) for cloxacillin - CLX and cefapirin - CFAP.

State of the art of environmentally friendly sample preparation approaches for determination of PBDEs and metabolites in environmental and biological samples: A critical review.

PubMed

Berton, Paula; Lana, Nerina B; Ríos, Juan M; García-Reyes, Juan F; Altamirano, Jorgelina C

2016-01-28

Green chemistry principles for developing methodologies have gained attention in analytical chemistry in recent decades. A growing number of analytical techniques have been proposed for determination of organic persistent pollutants in environmental and biological samples. In this light, the current review aims to present state-of-the-art sample preparation approaches based on green analytical principles proposed for the determination of polybrominated diphenyl ethers (PBDEs) and metabolites (OH-PBDEs and MeO-PBDEs) in environmental and biological samples. Approaches to lower the solvent consumption and accelerate the extraction, such as pressurized liquid extraction, microwave-assisted extraction, and ultrasound-assisted extraction, are discussed in this review. Special attention is paid to miniaturized sample preparation methodologies and strategies proposed to reduce organic solvent consumption. Additionally, extraction techniques based on alternative solvents (surfactants, supercritical fluids, or ionic liquids) are also commented in this work, even though these are scarcely used for determination of PBDEs. In addition to liquid-based extraction techniques, solid-based analytical techniques are also addressed. The development of greener, faster and simpler sample preparation approaches has increased in recent years (2003-2013). Among green extraction techniques, those based on the liquid phase predominate over those based on the solid phase (71% vs. 29%, respectively). For solid samples, solvent assisted extraction techniques are preferred for leaching of PBDEs, and liquid phase microextraction techniques are mostly used for liquid samples. Likewise, green characteristics of the instrumental analysis used after the extraction and clean-up steps are briefly discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

Simultaneous Determination of Perfluorinated Compounds in Edible Oil by Gel-Permeation Chromatography Combined with Dispersive Solid-Phase Extraction and Liquid Chromatography-Tandem Mass Spectrometry.

PubMed

Yang, Lili; Jin, Fen; Zhang, Peng; Zhang, Yanxin; Wang, Jian; Shao, Hua; Jin, Maojun; Wang, Shanshan; Zheng, Lufei; Wang, Jing

2015-09-30

A simple analytical method was developed for the simultaneous analysis of 18 perfluorinated compounds (PFCs) in edible oil. The target compounds were extracted by acetonitrile, purified by gel permeation chromatography (GPC) and dispersive solid-phase extraction (DSPE) using graphitized carbon black (GCB) and octadecyl (C18), and analyzed by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ES-MS/MS) in negative ion mode. Recovery studies were performed at three fortification levels. The average recoveries of all target PFCs ranged from 60 to 129%, with an acceptable relative standard deviation (RSD) (1-20%, n = 3). The method detection limits (MDLs) ranged from 0.004 to 0.4 μg/kg, which was significantly improved compared with the existing liquid-liquid extraction and cleanup method. The method was successfully applied for the analysis of all target PFCs in edible oil samples collected from markets in Beijing, China, and the results revealed that C6-C10 perfluorocarboxylic acid (PFCAs) and C7 perfluorosulfonic acid PFSAs were the major PFCs detected in oil samples.

Carboxylated graphene oxide/polyvinyl chloride as solid-phase extraction sorbent combined with ion chromatography for the determination of sulfonamides in cosmetics.

PubMed

Zhong, Zhixiong; Li, Gongke; Luo, Zhibin; Liu, Zhe; Shao, Yijuan; He, Wanwen; Deng, Jianchao; Luo, Xingling

2015-08-12

A carboxylated graphene oxide/polyvinyl chloride (CGO/PVC) material was prepared as a sorbent for the selective extraction of sulphonamides from complex sample. After being dispersed in buffer solution, sample was transferred into the prefabricated solid-phase extraction (SPE) column, which integrated extraction and cleanup into one single-step. A multi-response optimization based on the Box-Behnken design was used to optimize factors affecting extraction efficiency. Compared with the commonly commercial sorbents including MCX, WCX and C18, CGO/PVC hybrid material had higher extraction selectivity and capacity to sulphonamides. The limits of detection and quantification for seven target compounds were in the range of 3.4-7.1 μg/L and 11.4-23.7 μg/L, respectively. The self-assembly SPE cartridge was successfully used to enrich seven analytes in anti-acne cosmetics prior to ion chromatography detection with good recoveries of 87.8-102.0% and relative standard deviations of 1.2-6.4%, implying that this method was suitable for routine analysis of cosmetics. Copyright © 2015 Elsevier B.V. All rights reserved.

Simultaneous determination of nucleosides and their bases in Cordyceps sinensis and its substitutes by matrix solid-phase dispersion extraction and HPLC.

PubMed

Wang, Zhibing; Li, Na; Wang, Min; Wang, Yue; Du, Lin; Ji, Xiaofeng; Yu, Aimin; Zhang, Hanqi; Qiu, Fangping

2013-07-01

Nine nucleosides and nucleobases, including uracil, adenine, thymine, uridine, adenosine, thymidine, cytidine, guanosine, and cordycepin in natural Cordyceps sinensis, cultured Cordyceps mycelia, and Cordyceps fruiting bodies were extracted by matrix solid-phase dispersion (MSPD) and determined by HPLC. The experimental conditions for the MSPD extraction were optimized. Florisil was used as dispersant, petroleum ether as washing solvent, and methanol as elution solvent. The Florisil-to-sample ratio was selected to be 4:1 and no additional clean-up sorbent was needed. The calibration curves had good linear relationships (r > 0.9997). The LOD and LOQ were in the range of 12～79 and 41～265 ng/mL, respectively. The intra- and interday precision were lower than 8.3%. The recoveries were between 61.5 and 93.2%. The present method consumed less sample compared with ultrasonic extraction and heating reflux extraction (HRE). The extraction yields obtained by using the present method are much higher than those obtained by UE and comparable to those obtained by HRE. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Double-disk solid-phase extraction--Simultaneous cleanup and trace enrichment of herbicides and metabolites from environmental samples

USGS Publications Warehouse

Ferrar, Imma; Barceló, Damià; Thurman, E.M.

1999-01-01

Phenylurea and triazine herbicides, including some metabolites, were isolated from water and soil extracts by solid-phase extraction using a layered system of two extraction disks, a method called double-disk solid-phase extraction. The first disk consisted of strong anion exchange (SAX) of 10-μm styrene divinylbenzene (SDB) particles embedded in Teflon, and the second disk was a C18 disk of 10-μm particles also embedded in Teflon. A volume of 500 mL of water or aqueous soil extract is passed through the layered system with the SAX disk first. The purpose of the SAX disk is to remove the humic and fulvic acids from the water or aqueous soil extract by ion exchange through their carboxyl groups. Even during methanol elution of herbicides, the humic substances remain bound to the SAX disk with >85% retention. Elution with methanol results in more than 90% recovery of the herbicides from the layered extraction disks. Removal of the humic and fulvic acids results in greater sensitivity for diode array detection quantitation (0.05 μg/L for herbicides) by substantially reducing the absorbance of the humic peak on the LC chromatogram. The herbicides adsorb to the SAX disk either through hydrogen bonding to the anion-exchange sites or by hydrophobic interaction with the SDB surface of the anion-exchange disk. The method was tested for the analysis of natural water samples from the Mississippi Embayment, a cotton-growing area of the southeastern United States.

The selective cleanup of complex matrices and simultaneous separation of benzo[a]pyrene by solid-phase extraction with MgO microspheres as sorbents.

PubMed

Jin, Jing; Li, Yun; Zhang, Zhiping; Su, Fan; Qi, Peipei; Lu, Xianbo; Chen, Jiping

2011-12-23

A new method for the selective cleanup of complex matrices and simultaneous separation of benzo[a]pyrene (BaP) was developed in this study. This method was based on solid-phase extraction (SPE) using magnesium oxide microspheres as sorbents, and it eliminated interferences from various impurities, such as lipids, sulphur, pigments, halobenzenes, polychlorodibenzo-p-dioxins and polychlorodibenzofurans. Several parameters, including the volume of rinsing and eluting solvents, the type of loading solvents and SPE sorbents, were optimized systematically. The capability for impurity removal was verified by gel permeation chromatography, gas chromatography, and liquid chromatography. Compared to commercial sorbents (silica gel, florisil and alumina), MgO microspheres exhibited excellent performance in the selective isolation of BaP and removal of impurities. The proposed method was applied to detect BaP in complex samples (sediments, soils, fish, and porcine liver). The limit of quantification (LOQ) was 1.04 ngL(-1), and the resulting regression coefficient (r(2)) was greater than 0.999 over a broad concentration range (9.5-7600 ngL(-1)). In contrast to traditional methods, the proposed method can give rise to higher recovery (85.1-100.8%) and better selectivity with simpler operation and less consumption of organic solvents (20-40 mL). Copyright © 2011 Elsevier B.V. All rights reserved.

Multi-class analysis of new psychoactive substances and metabolites in hair by pressurized liquid extraction coupled to HPLC-HRMS.

PubMed

Montesano, Camilla; Vannutelli, Gabriele; Massa, Maristella; Simeoni, Maria Chiara; Gregori, Adolfo; Ripani, Luigi; Compagnone, Dario; Curini, Roberta; Sergi, Manuel

2017-05-01

In this paper, an analytical method has been developed and validated for the analysis of new psychoactive substances (NPS) and metabolites in hair samples. The method was based on pressurized liquid extraction (PLE) followed by solid-phase extraction (SPE) clean-up and high performance liquid chromatography-high resolution mass spectrometry (HPLC-HRMS) analysis. To evaluate extraction efficiency and the applicability of the method, hair samples were fortified by soaking in order to obtain a good surrogate for drug users' hair; the amount of incorporated drugs related to their lipophilicity, similarly to in vivo drug incorporation. To the best of our knowledge, this is the first method that allowed for the analysis of both cathinones (5) and synthetic cannabinoids (7) in hair with a single extraction procedure and chromatographic run. A phenethylamine (2C-T-4), 4- fluorophenylpiperazine and methoxetamine were also included showing that PLE coupled to SPE clean-up was suitable for a multi-class analysis of NPS in hair. In addition, the use of PLE significantly reduced hair analysis time: decontamination, incubation, clean-up, and liquid chromatography-mass spectrometry (LC-MS) analysis were carried out in approximately 45 min. The method was fully validated according to Scientific Working Group for Forensic Toxicology (SWGTOX) and Society of Hair Testing (SoHT) guidelines. Limit of quantification (LOQ) values ranged from 8 to 50 pg mg -1 for cathinones, phenetylamines and piperazines, and from 9 to 40 pg mg -1 for synthetic cannabinoids (10 pg mg -1 for methoxetamine). Matrix effects were below 15% for all the analytes, demonstrating the effectiveness of the clean-up step. Inaccuracy was lower than 9% in terms of bias. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Focused microwave-assisted extraction combined with solid-phase microextraction and gas chromatography-mass spectrometry for the selective analysis of cocaine from coca leaves.

PubMed

Bieri, Stefan; Ilias, Yara; Bicchi, Carlo; Veuthey, Jean-Luc; Christen, Philippe

2006-04-21

An effective combination of focused microwave-assisted extraction (FMAE) with solid-phase microextraction (SPME) prior to gas chromatography (GC) is described for the selective extraction and quantitative analysis of cocaine from coca leaves (Erythroxylum coca). This approach required switching from an organic extraction solvent to an aqueous medium more compatible with SPME liquid sampling. SPME was performed in the direct immersion mode with a universal 100 microm polydimethylsiloxane (PDMS) coated fibre. Parameters influencing this extraction step, such as solution pH, sampling time and temperature are discussed. Furthermore, the overall extraction process takes into account the stability of cocaine in alkaline aqueous solutions at different temperatures. Cocaine degradation rate was determined by capillary electrophoresis using the short end injection procedure. In the selected extraction conditions, less than 5% of cocaine was degraded after 60 min. From a qualitative point of view, a significant gain in selectivity was obtained with the incorporation of SPME in the extraction procedure. As a consequence of SPME clean-up, shorter columns could be used and analysis time was reduced to 6 min compared to 35 min with conventional GC. Quantitative results led to a cocaine content of 0.70 +/- 0.04% in dry leaves (RSD <5%) which agreed with previous investigations.

Optimization of a new method for extraction of cyanidin chloride and pelargonidin chloride anthocyanins with magnetic solid phase extraction and determination in fruit samples by HPLC with central composite design.

PubMed

Yari, Abdollah; Rashnoo, Saba

2017-11-01

Here, we are reporting a sensitive, simple and rapid method for the analysis of cyanidin chloride and pelargonidin chloride anthocyanins in cherry, sour cherry, pomegranate and barberry produced in Iran. The analytes were extracted with acetonitrile-hydrochloric acid (1% v/v) mixture under optimized pretreatment conditions. Clean-up of the extract from fruits was conducted by magnetic solid phase extraction using salicylic acid functionalized silica-coated magnetite nanoparticles (SCMNPs) as the adsorbent. The optimized conditions searched with central composite design. Working under optimum conditions specified as: SCMNPs modified with salicylic acid, sorbent contact time and sample 10min, mechanical stirring time 57.3min. HPLC with UV-detection was used for determination of the analytes. The limit of detection, LOD, obtained for the two anthocyanins were 0.02 and 0.03μgg -1 , respectively. The ranges of the spiked recoveries were 80.0-97.6 and 72.9-97.2%, with the relative standard deviations (RSD) of 2.1 and 2.5%, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

Design and development of molecularly imprinted polymers for the selective extraction of deltamethrin in olive oil: An integrated computational-assisted approach.

PubMed

Martins, Nuno; Carreiro, Elisabete P; Locati, Abel; Ramalho, João P Prates; Cabrita, Maria João; Burke, Anthony J; Garcia, Raquel

2015-08-28

This work firstly addresses the design and development of molecularly imprinted systems selective for deltamethrin aiming to provide a suitable sorbent for solid phase (SPE) extraction that will be further used for the implementation of an analytical methodology for the trace analysis of the target pesticide in spiked olive oil samples. To achieve this goal, a preliminary evaluation of the molecular recognition and selectivity of the molecularly imprinted polymers has been performed. In order to investigate the complexity of the mechanistic basis for template selective recognition in these polymeric matrices, the use of a quantum chemical approach has been attempted providing new insights about the mechanisms underlying template recognition, and in particular the crucial role of the crosslinker agent and the solvent used. Thus, DFT calculations corroborate the results obtained by experimental molecular recognition assays enabling one to select the most suitable imprinting system for MISPE extraction technique which encompasses acrylamide as functional monomer and ethylene glycol dimethacrylate as crosslinker. Furthermore, an analytical methodology comprising a sample preparation step based on solid phase extraction has been implemented using this "tailor made" imprinting system as sorbent, for the selective isolation/pre-concentration of deltamethrin from olive oil samples. Molecularly imprinted solid phase extraction (MISPE) methodology was successfully applied for the clean-up of spiked olive oil samples, with recovery rates up to 94%. Copyright © 2015 Elsevier B.V. All rights reserved.

Matrix solid-phase dispersion on column clean-up/pre-concentration as a novel approach for fast isolation of abuse drugs from human hair.

PubMed

Míguez-Framil, Martha; Moreda-Piñeiro, Antonio; Bermejo-Barrera, Pilar; Alvarez-Freire, Iván; Tabernero, María Jesús; Bermejo, Ana María

2010-10-08

A simple and fast sample pre-treatment method based on matrix solid-phase dispersion (MSPD) for isolating cocaine, benzoylecgonine (BZE), codeine, morphine and 6-monoacethylmorphine (6-MAM) from human hair has been developed. The MSPD approach consisted of using alumina (1.80 g) as a dispersing agent and 0.6M hydrochloric acid (4 mL) as an extracting solvent. For a fixed hair sample mass of 0.050 g, the alumina mass to sample mass ratio obtained was 36. A previously conditioned Oasis HLB cartridge (2 mL methanol, plus 2 mL ultrapure water, plus 1 mL of 0.2M/0.2M sodium hydroxide/boric acid buffer solution at pH 9.2) was attached to the end of the MSPD syringe for on column clean-up of the hydrochloric acid extract and for transferring the target compounds to a suitable solvent for gas chromatography (GC) analysis. Therefore, the adsorbed analytes were directly eluted from the Oasis HLB cartridges with 2 mL of 2% acetic acid in methanol before concentration by N(2) stream evaporation and dry extract derivatization with N-methyl-tert-butylsilyltrifluoroacetamide (BSTFA) and chlorotrimethylsilane (TMCS). The optimization/evaluation of all the factors affecting the MSPD and on column clean-up procedures has led to a fast sample treatment, and analytes extraction and pre-concentration can be finished in approximately 30 min. The developed method has been applied to eight hair samples from poli-drug abusers and measured analyte concentrations have been found to be statistically similar (95% confidence interval) to those obtained after a conventional enzymatic hydrolysis method (Pronase E). Copyright © 2010. Published by Elsevier B.V.

ASTM standards for fire debris analysis: a review.

PubMed

Stauffer, Eric; Lentini, John J

2003-03-12

The American Society for Testing and Materials (ASTM) recently updated its standards E 1387 and E 1618 for the analysis of fire debris. The changes in the classification of ignitable liquids are presented in this review. Furthermore, a new standard on extraction of fire debris with solid phase microextraction (SPME) was released. Advantages and drawbacks of this technique are presented and discussed. Also, the standard on cleanup by acid stripping has not been reapproved. Fire debris analysts that use the standards should be aware of these changes.

Microwave-assisted extraction at atmospheric pressure coupled to different clean-up methods for the determination of organophosphorus pesticides in olive and avocado oil.

PubMed

Fuentes, Edwar; Báez, María E; Díaz, Juan

2009-12-18

An effective extraction method was devised for the determination of organophosphorus pesticides (OPPs) in olive and avocado oil samples, using atmospheric pressure microwave-assisted liquid-liquid extraction (APMAE) and solid-phase extraction or low-temperature precipitation as clean-up step. A simple glass system equipped with an air-cooled condenser was designed as an extraction vessel. The pesticides were partitioned between acetonitrile and oil solution in hexane. Analytical determinations were carried out by gas chromatography-flame photometric detection and gas chromatography-tandem mass spectrometry, using a triple quadrupole mass analyzer, for confirmation purposes. Several factors influencing the extraction efficiency were investigated and optimized through fractional factorial design and Doehlert design. Under optimal conditions the recovery of pesticides from oil at 0.025 microg g(-1) ranged from 71% to 103%, except for fenthion in avocado oil, with RSDs < or = 13% (n=5). The LOQ for the entire method ranged from 0.004 to 0.015 microg g(-1). Finally, the proposed method was successfully applied to the extraction and determination of the selected pesticides in 20 commercially packed extra virgin olive oils and four commercially packed avocado oils produced in Chile. Detectable residues of different OPPs were observed in 85% of samples.

High-throughput screening for multi-class veterinary drug residues in animal muscle using liquid chromatography/tandem mass spectrometry with on-line solid-phase extraction.

PubMed

Tang, Hubert Po-On; Ho, Clare; Lai, Shirley Sau-Ling

2006-01-01

A rapid qualitative method using on-line column-switching liquid chromatography/tandem mass spectrometry (LC/MS/MS) was developed and validated for screening 13 target veterinary drugs: four macrolides - erythromycin A, josamycin (leucomycin A3), kitasamycin (leucomycin A5), and tylosin A; six (fluoro)quinolones - ciprofloxacin, danofloxacin, enrofloxacin, flumequine, oxolinic acid, and sarafloxacin; and lincomycin, virginiamycin M1, and trimethoprim in different animal muscles. Clindamycin, norfloxacin, nalidixic acid, oleandomycin, ormetoprim, and roxithromycin were used as the internal standards. After simple deproteination and analyte extraction of muscle samples using acetonitrile, the supernatant was subjected to on-line cleanup and direct analysis by LC/MS/MS. On-line cleanup with an extraction cartridge packed with hydrophilic-hydrophobic polymer sorbent followed by fast LC using a short C18 column resulted in a total analysis cycle of 6 min for 19 drugs. This screening method considerably reduced the time and the cost for the quantitative and confirmatory analyses. The application of a control point approach was also introduced and explained. Copyright (c) 2006 John Wiley & Sons, Ltd.

Molecularly imprinted polymer for selective extraction of malachite green from seawater and seafood coupled with high-performance liquid chromatographic determination.

PubMed

Lian, Ziru; Wang, Jiangtao

2012-12-01

In this paper, a highly selective sample cleanup procedure combining molecular imprinting technique (MIT) and solid-phase extraction (SPE) was developed for the isolation of malachite green in seawater and seafood samples. The molecularly imprinted polymer (MIP) was prepared using malachite green as the template molecule, methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the cross-linking monomer. The imprinted polymer and non-imprinted polymer were characterized by scanning electron microscope and static adsorption experiments. The MIP showed a high adsorption capacity and was used as selective sorbent for the SPE of malachite green. An off-line molecularly imprinted solid-phase extraction (MISPE) method followed by high-performance liquid chromatography with diodearray detection for the analysis of malachite green in seawater and seafood samples was also established. Finally, five samples were determined. The results showed that malachite green concentration in one seawater sample was at 1.30 μg L⁻¹ and the RSD (n=3) was 4.15%. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

Comparative study of different clean-up techniques for the determination of λ-cyhalothrin and cypermethrin in palm oil matrices by gas chromatography with electron capture detection.

PubMed

Muhamad, Halimah; Zainudin, Badrul Hisyam; Abu Bakar, Nor Kartini

2012-10-15

Solid phase extraction (SPE) and dispersive solid-phase extraction (d-SPE) were compared and evaluated for the determination of λ-cyhalothrin and cypermethrin in palm oil matrices by gas chromatography with an electron capture detector (GC-ECD). Several SPE sorbents such as graphitised carbon black (GCB), primary secondary amine (PSA), C(18), silica, and florisil were tested in order to minimise fat residues. The results show that mixed sorbents using GCB and PSA obtained cleaner extracts than a single GCB and PSA sorbents. The average recoveries obtained for each pesticide ranged between 81% and 114% at five fortification levels with the relative standard deviation of less than 7% in all cases. The limits of detection for these pesticides were ranged between 0.025 and 0.05 μg/g. The proposed method was applied successfully for the residue determination of both λ-cyhalothrin and cypermethrin in crude palm oil samples obtained from local mills throughout Malaysia. Copyright © 2012 Elsevier Ltd. All rights reserved.

Multiresidue analysis of sulfonamides, quinolones, and tetracyclines in animal tissues by ultra-high performance liquid chromatography-tandem mass spectrometry.

PubMed

Zhang, Zhiwen; Li, Xiaowei; Ding, Shuangyang; Jiang, Haiyang; Shen, Jianzhong; Xia, Xi

2016-08-01

A multiresidue method for the efficient identification and quantification of 38 compounds from 3 different classes of antibiotics (tetracyclines, sulfonamides, and quinolones) in animal tissues has been developed. The method optimization involved the selection of extraction solutions, comparison of different solid-phase extraction cartridges and different mobile phases. As a result, the samples were extracted with Mcllvaine and phosphate buffers, followed by clean-up step based on solid-phase extraction with Oasis HLB cartridge. All compounds were determined by ultra-high performance liquid chromatography-tandem mass spectrometry, in one single injection with a chromatographic run time of only 9min. The method efficiency was evaluated in 5 tissues including muscle, liver, and kidney, and the mean recoveries ranged from 54% to 102%, with inter-day relative standard deviation lower than 14%. The limits of quantification were between 0.5 and 10μg/kg, which were satisfactory to support future surveillance monitoring. The developed method was applied to the analysis of swine liver and chicken samples from local markets, and sulfamethazine was the most commonly detected compound in the animal samples, with the highest residue level of 998μg/kg. Copyright © 2016 Elsevier Ltd. All rights reserved.

High-throughput multipesticides residue analysis in earthworms by the improvement of purification method: Development and application of magnetic Fe3 O4 -SiO2 nanoparticles based dispersive solid-phase extraction.

PubMed

Sun, Yuhan; Qi, Peipei; Cang, Tao; Wang, Zhiwei; Wang, Xiangyun; Yang, Xuewei; Wang, Lidong; Xu, Xiahong; Wang, Qiang; Wang, Xinquan; Zhao, Changshan

2018-06-01

As a key representative organism, earthworms can directly illustrate the influence of pesticides on environmental organisms in soil ecosystems. The present work aimed to develop a high-throughput multipesticides residue analytical method for earthworms using solid-liquid extraction with acetonitrile as the solvent and magnetic material-based dispersive solid-phase extraction for purification. Magnetic Fe 3 O 4 nanoparticles were modified with a thin silica layer to form Fe 3 O 4 -SiO 2 nanoparticles, which were fully characterized by field-emission scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffractometry, and vibrating sample magnetometry. The Fe 3 O 4 -SiO 2 nanoparticles were used as the separation media in dispersive solid-phase extraction with primary secondary amine and ZrO 2 as the cleanup adsorbents to eliminate matrix interferences. The amounts of nanoparticles and adsorbents were optimized for the simultaneous determination of 44 pesticides and six metabolites in earthworms by liquid chromatography with tandem mass spectrometry. The method performance was systematically validated with satisfactory results. The limits of quantification were 20 μg/kg for all analytes studied, while the recoveries of the target analytes ranged from 65.1 to 127% with relative standard deviation values lower than 15.0%. The developed method was subsequently utilized to explore the bioaccumulation of bitertanol in earthworms exposed to contaminated soil, verifying its feasibility for real sample analysis. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous determination of 20 pharmacologically active substances in cow's milk, goat's milk, and human breast milk by gas chromatography-mass spectrometry.

PubMed

Azzouz, Abdelmonaim; Jurado-Sánchez, Beatriz; Souhail, Badredine; Ballesteros, Evaristo

2011-05-11

This paper reports a systematic approach to the development of a method that combines continuous solid-phase extraction and gas chromatography-mass spectrometry for the simultaneous determination of 20 pharmacologically active substances including antibacterials (chloramphenicol, florfenicol, pyrimethamine, thiamphenicol), nonsteroideal anti-inflammatories (diclofenac, flunixin, ibuprofen, ketoprofen, naproxen, mefenamic acid, niflumic acid, phenylbutazone), antiseptic (triclosan), antiepileptic (carbamazepine), lipid regulator (clofibric acid), β-blockers (metoprolol, propranolol), and hormones (17α-ethinylestradiol, estrone, 17β-estradiol) in milk samples. The sample preparation procedure involves deproteination of the milk, followed by sample enrichment and cleanup by continuous solid-phase extraction. The proposed method provides a linear response over the range of 0.6-5000 ng/kg and features limits of detection from 0.2 to 1.2 ng/kg depending on the particular analyte. The method was successfully applied to the determination of pharmacologically active substance residues in food samples including whole, raw, half-skim, skim, and powdered milk from different sources (cow, goat, and human breast).

A new method for microwave assisted ethanolic extraction of Mentha rotundifolia bioactive terpenoids.

PubMed

García-Sarrió, María Jesús; Sanz, María Luz; Sanz, Jesús; González-Coloma, Azucena; Cristina Soria, Ana

2018-04-14

A new microwave-assisted extraction (MAE) method using ethanol as solvent has been optimized by means of a Box-Behnken experimental design for the enhanced extraction of bioactive terpenoids from Mentha rotundifolia leaves; 100°C, 5 min, 1.125 g dry sample: 10 mL solvent and a single extraction cycle were selected as optimal conditions. Improved performance of MAE method in terms of extraction yield and/or reproducibility over conventional solid-liquid extraction and ultrasound assisted extraction was also previously assessed. A comprehensive characterization of MAE extracts was carried out by GC-MS. A total of 46 compounds, mostly terpenoids, were identified; piperitenone oxide and piperitenone were the major compounds determined. Several neophytadiene isomers were also detected for the first time in MAE extracts. Different procedures (solid-phase extraction and activated charcoal (AC) treatment) were also evaluated for clean-up of MAE extracts, with AC providing the highest enrichment in bioactive terpenoids. Finally, the MAE method here developed is shown as a green, fast, efficient and reproducible liquid extraction methodology to obtain M. rotundifolia bioactive extracts for further application, among others, as food preservatives. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of aminophenols and phenol in hair colorants by ultrasound-assisted solid-phase dispersion extraction coupled with ion chromatography.

PubMed

Zhong, Zhixiong; Li, Gongke; Wu, Rong; Zhu, Binghui; Luo, Zhibin

2014-08-01

A simple and reliable ultrasound-assisted solid-phase dispersion extraction coupled with ion chromatography was developed for the determination of aminophenols and phenol. The highly viscous hair colorant was dispersed in solvents using anhydrous sodium sulfite having dual functions of dispersant and antioxidant. The use of anhydrous sodium sulfite did not change the sample volume because it could completely dissolve in solution after matrix dispersion. The extraction and cleanup were combined in one single step for simplifying operation. The extraction process could be rapidly accomplished within 9 min with high sample throughput under the synergistic effects of vibration, ultrasound, and heating. Satisfactory linearity was observed with correlation coefficients higher than 0.9992, and the limits of detection varied from 0.02 to 0.09 mg/L. The applicability of the proposed method was demonstrated by measuring the concentrations of aminophenols and phenol in 32 different commercial hair color products. The recoveries ranged from 86.4-101.2% with the relative standard deviations in the range of 0.52-4.3%. The method offers an attractive alternative for the analysis of trace phenols in complex matrices. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Selective solid-phase extraction using a molecularly imprinted polymer for the analysis of patulin in apple-based foods.

PubMed

Lucci, Paolo; Moret, Sabrina; Bettin, Sara; Conte, Lanfranco

2017-01-01

The aim of this work was to evaluate the use of a molecularly imprinted polymer as a selective solid-phase extraction sorbent for the clean-up and pre-concentration of patulin from apple-based food products. Ultra high pressure liquid chromatography coupled to ultraviolet absorbance detection was used for the analysis of patulin. The molecularly imprinted polymer was applied, for the first time, to the determination of patulin in apple juice, puree and jam samples spiked within the maximum levels specified by the European Commission No. 1881/2006. High recoveries (>77%) were obtained. The method was validated and found to be linear in the range 2-100 μg/kg with correlation coefficients greater than 0.965 and repeatability relative standard deviation below 11% in all cases. Compared with dispersive solid-phase extraction (QuEChERS method) and octadecyl sorbent, the molecularly imprinted polymer showed higher recoveries and selectivity for patulin. The application of Affinisep molecularly imprinted polymer as a selective sorbent material for detection of patulin fulfilled the method performance criteria required by the Commission Regulation No. 401/2006, demonstrating the suitability of the technique for the control of patulin at low ppb levels in different apple-based foods such as juice, puree and jam samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Direct Sampling and Analysis from Solid Phase Extraction Cards using an Automated Liquid Extraction Surface Analysis Nanoelectrospray Mass Spectrometry System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walworth, Matthew J; ElNaggar, Mariam S; Stankovich, Joseph J

Direct liquid extraction based surface sampling, a technique previously demonstrated with continuous flow and autonomous pipette liquid microjunction surface sampling probes, has recently been implemented as the Liquid Extraction Surface Analysis (LESA) mode on the commercially available Advion NanoMate chip-based infusion nanoelectrospray ionization system. In the present paper, the LESA mode was applied to the analysis of 96-well format custom solid phase extraction (SPE) cards, with each well consisting of either a 1 or 2 mm diameter monolithic hydrophobic stationary phase. These substrate wells were conditioned, loaded with either single or multi-component aqueous mixtures, and read out using the LESAmore » mode of a TriVersa NanoMate or a Nanomate 100 coupled to an ABI/Sciex 4000QTRAPTM hybrid triple quadrupole/linear ion trap mass spectrometer and a Thermo LTQ XL linear ion trap mass spectrometer. Extraction conditions, including extraction/nanoESI solvent composition, volume, and dwell times, were optimized in the analysis of targeted compounds. Limit of detection and quantitation as well as analysis reproducibility figures of merit were measured. Calibration data was obtained for propranolol using a deuterated internal standard which demonstrated linearity and reproducibility. A 10x increase in signal and cleanup of micromolar Angiotensin II from a concentrated salt solution was demonstrated. Additionally, a multicomponent herbicide mixture at ppb concentration levels was analyzed using MS3 spectra for compound identification in the presence of isobaric interferences.« less

Optimization and application of parallel solid-phase extraction coupled with ultra-high performance liquid chromatography-tandem mass spectrometry for the determination of 11 aminoglycoside residues in honey and royal jelly.

PubMed

Wang, Xinran; Yang, Shupeng; Li, Yi; Zhang, Jinzhen; Jin, Yue; Zhao, Wen; Zhang, Yongxin; Huang, Jingping; Wang, Peng; Wu, Cuiling; Zhou, Jinhui

2018-03-23

A robust and sensitive method of solid-phase extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was established and performed for the simultaneous determination of eleven aminoglycosides (AGs) in royal jelly and honey. After sample extraction by a phosphate buffer containing trichloroacetic acid (TCA) and ethylenediaminetetracetic acid disodium salt (Na 2 EDTA), the extraction solution was subjected to a parallel solid-phase extraction for clean-up prior to the LC-MS/MS analysis. The same method was applied to analyze two completely different matrices, honey and royal jelly. Good sensitivity, repeatability, and recovery were obtained by using the mobile phase without an ion-pairing reagent such as heptafluorobutyric acid (HFBA) or sodium heptanesulfonate. The calibration curves of the honey and royal jelly samples exhibited a good linear response (R 2  > 0.99) at six concentrations in the range of 10-1000 μg/mL. The limit of quantification (LOQ) of the AGs ranged from 10 to 25 μg/kg in the honey and from 12.5 to 25 μg/kg in the royal jelly. The recoveries of the AGs for the honey and royal jelly samples were in the range of 79.48% to 108.95% and 74.61% to 113.70% respectively and the relative standard deviations (RSDs) were between 1.23% and 9.59%, and between 1.51% and 9.98%, respectively. The proposed approach has been allowed in China as a reference method for the simultaneous determination of eleven AGs in honey and royal jelly. Copyright © 2018 Elsevier B.V. All rights reserved.

Method development for the analysis of organophosphate and pyrethroid insecticides at low parts per trillion levels in water.

PubMed

Wang, Dongli; Weston, Donald P; Lydy, Michael J

2009-06-15

In the current study, organophosphate and pyrethroid insecticides including diazinon, chlorpyrifos, bifenthrin, fenpropathrin, permethrin, lambda-cyhalothrin, cyfluthrin, cypermethrin, esfenvalerate and deltamethrin were analyzed in laboratory and field-collected water samples. Water samples were extracted and analyzed by gas chromatography/electron capture detector (GC/ECD) and gas chromatography/nitrogen-phosphorous detector (GC/NPD). Comparison of results from liquid-liquid extraction and subsequent normal phase solid-phase extraction cleanup (LLE-NPSPE), and reversed phase solid-phase extraction (RPSPE) showed that LLE-NPSPE was the better choice to extract trace amounts of pesticides from water. Pesticide recoveries from four spiked water samples using LLE-NPSPE ranged from 63.2 to 148.8% at four spiking concentrations. Method detection limits were 0.72-1.69 ng/L using four different water sources. The stability of the target pesticides in lake water was investigated at 4 degrees C for 1h, 1d, 4d, and 7d under three conditions: (1) water samples only; (2) with 20 mL hexane used as a keeper solvent; and (3) with acidification to pH 2 with HCl. Results showed that water storage without treatment resulted in slow degradation of some pesticides with storage time, storage using water acidification led to significant degradation and loss of diazinon and chlorpyrifos, while water storage with hexane as a keeper solvent showed good stability for all of the target pesticides over the 7d storage period.

Accelerated solvent extraction followed by on-line solid-phase extraction coupled to ion trap LC/MS/MS for analysis of benzalkonium chlorides in sediment samples

USGS Publications Warehouse

Ferrer, I.; Furlong, E.T.

2002-01-01

Benzalkonium chlorides (BACs) were successfully extracted from sediment samples using a new methodology based on accelerated solvent extraction (ASE) followed by an on-line cleanup step. The BACs were detected by liquid chromatography/ion trap mass spectrometry (LC/MS) or tandem mass spectrometry (MS/MS) using an electrospray interface operated in the positive ion mode. This methodology combines the high efficiency of extraction provided by a pressurized fluid and the high sensitivity offered by the ion trap MS/MS. The effects of solvent type and ASE operational variables, such as temperature and pressure, were evaluated. After optimization, a mixture of acetonitrile/water (6:4 or 7:3) was found to be most efficient for extracting BACs from the sediment samples. Extraction recoveries ranged from 95 to 105% for C12 and C14 homologues, respectively. Total method recoveries from fortified sediment samples, using a cleanup step followed by ASE, were 85% for C12BAC and 79% for C14-BAC. The methodology developed in this work provides detection limits in the subnanogram per gram range. Concentrations of BAC homologues ranged from 22 to 206 ??g/kg in sediment samples from different river sites downstream from wastewater treatment plants. The high affinity of BACs for soil suggests that BACs preferentially concentrate in sediment rather than in water.

Confirmatory and quantitative analysis of beta-lactam antibiotics in bovine kidney tissue by dispersive solid-phase extraction and liquid chromatography-tandem mass spectrometry.

PubMed

Fagerquist, Clifton K; Lightfield, Alan R; Lehotay, Steven J

2005-03-01

A simple, rapid, rugged, sensitive, and specific method for the confirmation and quantitation of 10 beta-lactam antibiotics in fortified and incurred bovine kidney tissue has been developed. The method uses a simple solvent extraction, dispersive solid-phase extraction (dispersive-SPE) cleanup, and liquid chromatography-tandem mass spectrometry (LC/MS/MS) for confirmation and quantitation. Dispersive-SPE greatly simplifies and accelerates sample cleanup and improves overall recoveries compared with conventional SPE cleanup. The beta-lactam antibiotics tested were as follows: deacetylcephapirin (an antimicrobial metabolite of cephapirin), amoxicillin, desfuroylceftiofur cysteine disulfide (DCCD, an antimicrobial metabolite of ceftiofur), ampicillin, cefazolin, penicillin G, oxacillin, cloxacillin, naficillin, and dicloxacillin. Average recoveries of fortified samples were 70% or better for all beta-lactams except DCCD, which had an average recovery of 58%. The LC/MS/MS method was able to demonstrate quantitative recoveries at established tolerance levels and provide confirmatory data for unambiguous analyte identification. The method was also tested on 30 incurred bovine kidney samples obtained from the USDA Food Safety and Inspection Service, which had previously tested the samples using the approved semiquantitative microbial assay. The results from the quantitative LC/MS/MS analysis were in general agreement with the microbial assay for 23 samples although the LC/MS/MS method was superior in that it could specifically identify which beta-lactam was present and quantitate its concentration, whereas the microbial assay could only identify the type of beta-lactam present and report a concentration with respect to the microbial inhibition of a penicillin G standard. In addition, for 6 of the 23 samples, LC/MS/MS analysis detected a penicillin and a cephalosporin beta-lactam, whereas the microbial assay detected only a penicillin beta-lactam. For samples that do not fall into the "general agreement" category, the most serious discrepancy involves two samples where the LC/MS/MS method detected a violative level of a cephalosporin beta-lactam (deacetylcephapirin) in the first sample and a possibly violative level of desfuroylceftiofur in the second, whereas the microbial assay identified the two samples as having only violative levels of a penicillin beta-lactam.

Multi-residue method for the analysis of 85 current-use and legacy pesticides in bed and suspended sediments

USGS Publications Warehouse

Smalling, K.L.; Kuivila, K.M.

2008-01-01

A multi-residue method was developed for the simultaneous determination of 85 current-use and legacy organochlorine pesticides in a single sediment sample. After microwave-assisted extraction, clean-up of samples was optimized using gel permeation chromatography and either stacked carbon and alumina solid-phase extraction cartridges or a deactivated Florisil column. Analytes were determined by gas chromatography with ion-trap mass spectrometry and electron capture detection. Method detection limits ranged from 0.6 to 8.9 ??g/kg dry weight. Bed and suspended sediments from a variety of locations were analyzed to validate the method and 29 pesticides, including at least 1 from every class, were detected.

Multiwall carbon nanotube- zirconium oxide nanocomposite hollow fiber solid phase microextraction for determination of polyaromatic hydrocarbons in water, coffee and tea samples.

PubMed

Yazdi, Mahnaz Nozohour; Yamini, Yadollah; Asiabi, Hamid

2018-06-15

The purpose of this study was to evaluate the application of hollow fiber solid-phase microextraction (HF-SPME) followed by HPLC-UV to determine the ultra-trace amounts of polycyclic aromatic hydrocarbons (PAHs) as model analytes in complex coffee and tea samples. HF-SPME can be effectively used as an alternative to the direct immersion SPME (DI-SPME) method in complex matrices. The DI-SPME method suffers from serious limitation in dirty and complicated matrices with low sample clean-up, while the HF-SPME method has high clean-up and selectivity due to the high porosity of hollow fiber that can pick out analyte from complicated matrices. As a hollow fiber sorbent, a novel multiwall carbon nanotube/zirconium oxide nanocomposite (MWCNT/ZrO 2 ) was fabricated. The excellent adsorption of PAHs on the sorbent was attributed to the dominant roles of π-π stacking interaction and hydrophobic interaction. Under the optimized extraction conditions, the wide linear range of 0.1-200 μg L -1 with coefficients of determination better than 0.998 and low detection limits of 0.033-0.16 μg L -1 with satisfactory precision (RSD < 6.6%) were obtained. The relative recoveries obtained by spiking the PAHs in water, coffee and tea samples were in the range of 92.0-106.0%. Compared to other methods, MWCNT/ZrO 2 hollow fiber solid phase microextraction demonstrated a good capability for determination of PAHs in complex coffee and tea samples. Copyright © 2018 Elsevier B.V. All rights reserved.

Oxysterols in cosmetics-Determination by planar solid phase extraction and gas chromatography-mass spectrometry.

PubMed

Schrack, S; Hohl, C; Schwack, W

2016-11-18

Sterol oxidation products (SOPs) are linked to several toxicological effects. Therefore, investigation of potential dietary uptake sources particularly food of animal origin has been a key issue for these compounds. For the simultaneous determination of oxysterols from cholesterol, phytosterols, dihydrolanosterol and lanosterol in complex cosmetic matrices, planar solid phase extraction (pSPE) was applied as clean-up tool. SOPs were first separated from more non-polar and polar matrix constituents by normal phase thin-layer chromatography and then focussed into one target zone. Zone extraction was performed with the TLC-MS interface, followed by gas chromatography-mass spectrometry analysis. pSPE showed to be effective for cleaning up cosmetic samples as sample extracts were free of interferences, and gas chromatographic columns did not show any signs of overloading. Recoveries were between 86 and 113% with relative standard deviations of below 10% (n=6). Results of our market survey in 2016 showed that some cosmetics with ingredients of plant origin contained phytosterol oxidation products (POPs) in the low ppm range and therefore in line with levels reported for food. In lanolin containing products, total SOPs levels (cholesterol oxidation products (COPs), lanosterol oxidation products (LOPs), dihydrolanosterol oxidation products (DOPs)) being in the low percent range exceeded reported levels for food by several orders of magnitudes. Copyright © 2016 Elsevier B.V. All rights reserved.

Quantitation of acrylamide in foods by high-resolution mass spectrometry.

PubMed

Troise, Antonio Dario; Fiore, Alberto; Fogliano, Vincenzo

2014-01-08

Acrylamide detection still represents one of the hottest topics in food chemistry. Solid phase cleanup coupled to liquid chromatography separation and tandem mass spectrometry detection along with GC-MS detection are nowadays the gold standard procedure for acrylamide quantitation thanks to high reproducibility, good recovery, and low relative standard deviation. High-resolution mass spectrometry (HRMS) is particularly suitable for the detection of low molecular weight amides, and it can provide some analytical advantages over other MS techniques. In this paper a liquid chromatography (LC) method for acrylamide determination using HRMS detection was developed and compared to LC coupled to tandem mass spectrometry. The procedure applied a simplified extraction, no cleanup steps, and a 4 min chromatography. It proved to be solid and robust with an acrylamide mass accuracy of 0.7 ppm, a limit of detection of 2.65 ppb, and a limit of quantitation of 5 ppb. The method was tested on four acrylamide-containing foods: cookies, French fries, ground coffee, and brewed coffee. Results were perfectly in line with those obtained by LC-MS/MS.

Simultaneous and rapid determination of deoxynivalenol and its acetylate derivatives in wheat flour and rice by ultra high performance liquid chromatography with photo diode array detection.

PubMed

Xu, Jiao-Jiao; Zhou, Jian; Huang, Bai-Fen; Cai, Zeng-Xuan; Xu, Xiao-Min; Ren, Yi-Ping

2016-06-01

A simple and reliable method of ultra high performance liquid chromatography coupled with photo-diode array detection has been proposed for the simultaneous determination of deoxynivalenol and its acetylated derivatives in wheat flour and rice, especially focusing on the optimization of sample extraction, cleanup, and chromatographic separation conditions. Sample pretreatment consisted of a first step using a quick, easy, cheap, effective, rugged, and safe based extraction procedure and a subsequent cleanup step based on solid-phase extraction. The method was extensively validated in wheat flour and rice, obtaining satisfactory analytical performance with good linearity (R(2) ≥ 0.999), acceptable recoveries (80.0-104.4%), and repeatability (RSDs 1.3-10.7%). The limits of detection (21.7-57.4 μg/kg) and quantitation (72.3-191.4 μg/kg) for deoxynivalenols were lower than those usually permitted by various countries' legislation in these food matrices. The method was applied to 34 wheat and rice samples. The results were further compared with results of ultra high performance liquid chromatography with electrospray ionization tandem mass spectrometry. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimization of solid-phase extraction and liquid chromatography-tandem mass spectrometry for simultaneous determination of capilliposide B and its active metabolite in rat urine and feces: Overcoming nonspecific binding.

PubMed

Cheng, Zhongzhe; Zhou, Xing; Li, Wenyi; Hu, Bingying; Zhang, Yang; Xu, Yong; Zhang, Lin; Jiang, Hongliang

2016-11-30

Capilliposide B, a novel oleanane triterpenoid saponin isolated from Lysimachia capillipes Hemsl, showed significant anti-tumor activities in recent studies. To characterize the excretion of Capilliposide B, a reliable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous determination of Capilliposide B and its active metabolite, Capilliposide A in rat urine and feces. Sample preparation using a solid-phase extraction procedure was optimized by acidification of samples at various degrees, providing extensive sample clean-up with a high extraction recovery. In addition, rat urinary samples were pretreated with CHAPS, an anti-adsorptive agent, for overcoming nonspecific analytes adsorption during sample storage and process. The method validation was conducted over the curve range of 10.0-5000ng/ml for both analytes. The intra- and inter-day precision and accuracy of the QC samples showed ≤11.0% RSD and -10.4-12.8% relative error. The method was successfully applied to an excretion study of Capilliposide B following intravenous administration. Copyright © 2016 Elsevier B.V. All rights reserved.

Procedure for the determination of retinol and alpha-tocopherol in poultry tissues using capillary gas chromatography with solvent venting injection.

PubMed

Maraschiello, C; García Regueiro, J A

1998-08-28

A procedure designed for the determination of retinol (vitamin A) and alpha-tocopherol (vitamin E) in poultry tissues has been developed. The procedure involves lipid extraction, saponification, solid-phase clean-up and capillary gas chromatography (cGC). Retinol and alpha-tocopherol were determined separately by cGC-flame ionisation detection using a fused-silica open tubular capillary column, 30 m x 0.25 mm I.D. coated with 5% phenylmethylsilicone and with a film thickness of 0.25 micron. Solvent extraction followed by saponification were sufficient to provide a purified extract which was directly analyzed for retinol by cGC in the solvent venting mode. However, in order to accurately determine alpha-tocopherol by cGC, further purification of the extract by solid-phase extraction was necessary. A silica SPE column was used to remove interfering cholesterol from the extract. alpha-Tocopherol was analyzed in its derivatized form. Absolute and relative recoveries for both vitamins from spiked samples were evaluated. Absolute and relative recoveries ranging from 80 to 95% were obtained for both compounds. 5 alpha-Cholestane and alpha-tocopheryl acetate were used as internal standards. Poultry muscle meat and liver tissue were analyzed for their retinol and alpha-tocopherol content and the peaks detected by cGC were confirmed by cGC-mass spectrometry.

Analysis of psilocin, bufotenine and LSD in hair.

PubMed

Martin, Rafaela; Schürenkamp, Jennifer; Gasse, Angela; Pfeiffer, Heidi; Köhler, Helga

2015-03-01

A method for the simultaneous extraction of the hallucinogens psilocin, bufotenine, lysergic acid diethylamide (LSD) as well as iso-LSD, nor-LSD and O-H-LSD from hair with hydrochloride acid and methanol is presented. Clean-up of the hair extracts is performed with solid phase extraction using a mixed-mode cation exchanger. Extracts are measured with liquid chromatography coupled with electrospray tandem mass spectrometry. The method was successfully validated according to the guidelines of the 'Society of Toxicological and Forensic Chemistry' (GTFCh). To obtain reference material hair was soaked in a solution of the analytes in dimethyl sulfoxide/methanol to allow incorporation into the hair. These fortified hair samples were used for method development and can be employed as quality controls. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Solid-phase extraction clean-up of ciguatoxin-contaminated coral fish extracts for use in the mouse bioassay.

PubMed

Wong, Chun Kwan; Hung, Patricia; Lee, Kellie L H; Kam, Kai Man

2009-02-01

Florisil solid-phase extraction (SPE) cartridges were used for purifying ciguatoxin (CTX)-contaminated coral fish extracts, with the aim of removing extracted lipid but retaining optimal level of CTXs in the purified fractions. The CTX-containing fraction (target fraction) in fish ether extract was isolated and purified by eluting through a commercially available Florisil cartridge with hexane-acetone-methanol solvent mixtures of increasing polarity (hexane-acetone (4:1, v/v) < acetone-methanol (7:3, v/v) < 100% methanol). Application of Florisil SPE using acetone-methanol (7:3, v/v) condition facilitated the separation of 4.2 +/- 0.4 mg (mean +/- standard error of the mean (SEM)) of purified target fraction from 20 mg ether extract with good retention of CTXs. The mouse bioassay was used to demonstrate that the average CTX recovery of the target fraction from CTX-spiked samples was 75.8% +/- 3.3%, which was significantly increased by 96.7% +/- 15% when compared with CTX recovery from ether extracts (44.8% +/- 5.2%) without performing SPE purification. Over 70% of non-target lipids were removed in which no CTX toxicity was found. Moreover, the target fractions of both CTX-spiked and naturally CTX-contaminated samples gave more prominent toxic responses of hypothermia and/or induced more rapid death of the mice. The use of acetone-methanol (7:3, v/v) condition in the elution could significantly improve overall recovery of CTXs, while minimizing the possible interferences of lipid matrix from co-extractants on mice.

Development of an analytical procedure to study linear alkylbenzenesulphonate (LAS) degradation in sewage sludge-amended soils.

PubMed

Comellas, L; Portillo, J L; Vaquero, M T

1993-12-24

A procedure for determining linear alkylbenzenesulphonates (LASs) in sewage sludge and amended soils has been developed. Extraction by sample treatment with 0.5 M potassium hydroxide in methanol and reflux was compared with a previously described extraction procedure in Soxhlet with methanol and solid sodium hydroxide in the sample. Repeatability results were similar with savings in extraction time, solvents and evaporation time. A clean-up method involving a C18 cartridge has been developed. Analytes were quantified by a reversed-phase HPLC method with UV and fluorescence detectors. Recoveries obtained were higher than 84%. The standing procedure was applied to high doses of sewage sludge-amended soils (15%) with increasing quantities of added LASs. Degradation data for a 116-day period are presented.

Molecularly imprinted polymer cartridges coupled on-line with high performance liquid chromatography for simple and rapid analysis of dextromethorphan in human plasma samples.

PubMed

Moein, Mohammad Mahdi; Javanbakht, Mehran; Akbari-Adergani, Behrouz

2011-04-01

In this paper, a novel method is described for automated determination of dextromethorphan in biological fluids using molecularly imprinted solid-phase extraction (MISPE) as a sample clean-up technique combined with high performance liquid chromatography (HPLC). The water-compatible molecularly imprinted polymers (MIPs) were prepared using methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linker, chloroform as porogen and dextromethorphan as template molecule. These imprinted polymers were used as solid-phase extraction sorbent for the extraction of dextromethorphan from human plasma samples. Various parameters affecting the extraction efficiency of the MIP cartridges were evaluated. The high selectivity of the sorbent coupled to the high performance liquid chromatographic system permitted a simple and rapid analysis of this drug in plasma samples with limits of detection (LOD) and quantification (LOQ) of 0.12 ng/mL and 0.35 ng/mL, respectively. The MIP selectivity was evaluated by analyzing of the dextromethorphan in presence of several substances with similar molecular structures and properties. Results from the HPLC analyses showed that the recoveries of dextromethorphan using MIP cartridges from human plasma samples in the range of 1-50 ng/mL were higher than 87%. Copyright © 2011 Elsevier B.V. All rights reserved.

Multi-residue determination of 47 organic compounds in water, soil, sediment and fish-Turia River as case study.

PubMed

Carmona, Eric; Andreu, Vicente; Picó, Yolanda

2017-11-30

A sensitive and reliable method based on solid-liquid extraction (SLE) using McIlvaine-Na 2 EDTA buffer (pH=4.5)-methanol and solid-phase extraction (SPE) clean up prior to ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) was applied to determine 47 organic contaminants in fish, soil and sediments. The SPE procedure to clean-up the extracts was also used as extraction method to determine these compounds in water. Recoveries ranged from 38 to 104% for all matrices with RSDs<30%. Limits of Quantification for the target compounds were in the range of 10-50ng/g for soil, 2-40ng/g for sediment, 5-30ng/g for fish and 0.3-26ng/L for water. Furthermore, the proposed method was compared to QuEChERS (widely used for environmental matrices) that involves extraction with buffered acetonitrile (pH 5.5) and dispersive SPE clean-up. The results obtained (recoveries>50% for 36 compounds in front of 9, matrix effect<20% for 31 compounds against 21, and LOQs <25ngg -1 for 38 compounds against 22) indicates that the proposed method is more efficient than QuEChERS, The method was applied to monitoring these compounds along the Turia River. In river waters, Paracetamol (175ngL -1 ), ibuprofen (153ngL -1 ) and bisphenol A (41ngL -1 ) were the compounds most frequently detected while in sediments were vildagliptin (7ngg -1 ) and metoprolol (31ngg -1 ) and in fish, bisphenol A (33ngg -1 ) or sulfamethoxazole (13ngg -1 ). Copyright © 2017 Elsevier B.V. All rights reserved.

Multi-residue analysis of 36 priority and emerging pollutants in marine echinoderms (Holothuria tubulosa) and marine sediments by solid-liquid extraction followed by dispersive solid phase extraction and liquid chromatography-tandem mass spectrometry analysis.

PubMed

Martín, J; Zafra-Gómez, A; Hidalgo, F; Ibáñez-Yuste, A J; Alonso, E; Vilchez, J L

2017-05-01

Marine echinoderms are filter-feeding invertebrates widely distributed along the coasts, and which are therefore extensively exposed to anthropogenic xenobiotics. They can serve as good sentinels for monitoring a large variety of contaminants in marine ecosystems. In this context, a multi-residue analytical method has been validated and applied to Holothuria tubulosa specimens and marine sediments for the determination of 36 organic compounds, which belong to some of the most problematic groups of emerging and priority pollutants (perfluoroalkyl compounds, estrogens, parabens, benzophenones, plasticizers, surfactants, brominated flame retardants and alkylphenols). Lyophilization of samples prior to solvent extraction and clean-up of extracts with C18, followed by liquid chromatography-tandem mass spectrometry analysis, is proposed. A Box-Behnken design was used for optimization of the most influential variables affecting the extraction and clean-up steps. For validation, matrix-matched calibration and recovery assay were applied. Linearity (% r 2 ) higher than 99%, recoveries between 80% and 114% (except in LAS and NP1EO), RSD (precision) lower than 15% and limits of quantification between 0.03 and 12.5ngg -1 dry weight (d.w.) were achieved. The method was applied to nine samples of Holothuria collected along the coast of Granada (Spain), and to marine sediments around the animals. The results demonstrated high bioaccumulation of certain pollutants. A total of 25 out of the 36 studied compounds were quantified, being surfactants, alkylphenols, perfluoroalkyl compounds, triclocarban and parabens the most frequently detected. Nonylphenol was found in the highest concentration (340 and 323ngg -1 d.w. in sediment and Holothuria samples, respectively). Copyright © 2017 Elsevier B.V. All rights reserved.

Multi-residue determination of 171 pesticides in cowpea using modified QuEChERS method with multi-walled carbon nanotubes as reversed-dispersive solid-phase extraction materials.

PubMed

Han, Yongtao; Song, Le; Zou, Nan; Chen, Ronghua; Qin, Yuhong; Pan, Canping

2016-09-15

A rapid and sensitive method for the determination of 171 pesticides in cowpea was developed using multi-walled carbon nanotubes (MWCNTs) as reversed-dispersive solid-phase (r-DSPE) extraction materials. The clean-up performance of MWCNTs was proved to be obviously superior to PSA and GCB. This method was validated on cowpea spiked at 0.01 and 0.1mgkg(-1) with five replicates. The mean recoveries for 169 pesticides ranged from 74% to 129% with relative standard deviations (RSDs) (n=5) lower than 16.4%, except diflufenican and quizalofop-ethyl. Good linearity for all pesticides was obtained with the calibration curve coefficients (R(2)) larger than 0.9970. The limit of detection (LODs) and limit of quantification (LOQs) for the 171 pesticides ranged from 0.001 to 0.003mgkg(-1) and from 0.002 to 0.009mgkg(-1), respectively. The method was demonstrated to be reliable and sensitive for the routine monitoring of the 171 pesticides in cowpea samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Determination of novel brominated flame retardants and polybrominated diphenyl ethers in serum using gas chromatography-mass spectrometry with two simplified sample preparation procedures.

PubMed

Gao, Le; Li, Jian; Wu, Yandan; Yu, Miaohao; Chen, Tian; Shi, Zhixiong; Zhou, Xianqing; Sun, Zhiwei

2016-11-01

Two simple and efficient pretreatment procedures have been developed for the simultaneous extraction and cleanup of six novel brominated flame retardants (NBFRs) and eight common polybrominated diphenyl ethers (PBDEs) in human serum. The first sample pretreatment procedure was a quick, easy, cheap, effective, rugged, and safe (QuEChERS)-based approach. An acetone/hexane mixture was employed to isolate the lipid and analytes from the serum with a combination of MgSO 4 and NaCl, followed by a dispersive solid-phase extraction (d-SPE) step using C18 particles as a sorbent. The second sample pretreatment procedure was based on solid-phase extraction. The sample extraction and cleanup were conducted directly on an Oasis HLB SPE column using 5 % aqueous isopropanol, concentrated sulfuric acid, and 10 % aqueous methanol, followed by elution with dichloromethane. The NBFRs and PBDEs were then detected using gas chromatography-negative chemical ionization mass spectrometry (GC-NCI MS). The methods were assessed for repeatability, accuracy, selectivity, limits of detection (LODs), and linearity. The results of spike recovery experiments in fetal bovine serum showed that average recoveries ranged from 77.9 % to 128.8 % with relative standard deviations (RSDs) from 0.73 % to 12.37 % for most of the analytes. The LODs for the analytes in fetal bovine serum ranged from 0.3 to 50.8 pg/mL except for decabromodiphenyl ethane. The proposed method was successfully applied to the determination of the 14 brominated flame retardants in human serum. The two pretreatment procedures described here are simple, accurate, and precise, and are suitable for the routine analysis of human serum. Graphical Abstract Workflow of a QuEChERS-based approach (top) and an SPE-based approach (bottom) for the detection of PBDEs and NBFRs in serum.

Pipette-tip solid-phase extraction using polypyrrole as efficient adsorbent for extraction of avermectins and milbemycins in milk.

PubMed

Florez, Diego Hernando Ângulo; Teixeira, Roseane Andrade; da Silva, Ricky Cássio Santos; Pires, Bruna Carneiro; Dutra, Flávia Viana Avelar; Borges, Keyller Bastos

2018-05-01

In this work, we developed a HPLC method for the multidetermination of avermectins (AVM) (abamectin-ABA 1b and ABA 1a, eprinomectin-EPR, and ivermectin-IVM) and milbemycins (moxidectin-MOX) in milk samples using polypyrrole (PPy) as adsorbent material in pipette-tip solid-phase extraction (PT-PPy-SPE). PPy was characterized by scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, and X-ray diffraction and the data agreed with the literature. The sample preparation included the clean-up of the milk by protein precipitation (PP) with acetonitrile and extraction of the analytes by PT-PPy-SPE. The chromatographic method was developed in reverse phase and isocratic mode with flow rate at 1.2 mL min -1 and ultraviolet detection at 250 nm. The mobile phase composition was acetonitrile:methanol:water (55:25:20, v/v/v). The studied parameters and the optimized conditions for the sample preparation were washing solvent (300 μL water), volume and type of eluent (500 μL methanol), volume and pH of sample (1 mL and pH 10), amount of adsorbent material (50 mg PPy), and without addition of salt (NaCl). The method was linear over the concentration range from 20 to 3000 ng mL -1 with coefficients of correlation (r) ≥ 0.99 for all analytes and recoveries around 100%. The method developed and validated was used for the analyses of real milk samples from cow treated with Ivomec ® (IVM 3.5%), in which were found 21.51 ± 2.94 ng mL -1 of IVM. Finally, the results proved that PT-PPy-SPE coupled to HPLC-UV was economical, simple, and easy-to-perform technique. Graphical abstract Pipette-tip solid phase extraction using polypirrole as adsorbent material for determination of avermectins and milbemycins in milk.

Applications of reversible covalent chemistry in analytical sample preparation.

PubMed

Siegel, David

2012-12-07

Reversible covalent chemistry (RCC) adds another dimension to commonly used sample preparation techniques like solid-phase extraction (SPE), solid-phase microextraction (SPME), molecular imprinted polymers (MIPs) or immuno-affinity cleanup (IAC): chemical selectivity. By selecting analytes according to their covalent reactivity, sample complexity can be reduced significantly, resulting in enhanced analytical performance for low-abundance target analytes. This review gives a comprehensive overview of the applications of RCC in analytical sample preparation. The major reactions covered include reversible boronic ester formation, thiol-disulfide exchange and reversible hydrazone formation, targeting analyte groups like diols (sugars, glycoproteins and glycopeptides, catechols), thiols (cysteinyl-proteins and cysteinyl-peptides) and carbonyls (carbonylated proteins, mycotoxins). Their applications range from low abundance proteomics to reversible protein/peptide labelling to antibody chromatography to quantitative and qualitative food analysis. In discussing the potential of RCC, a special focus is on the conditions and restrictions of the utilized reaction chemistry.

Quantitation of (R)- and (S)-linalool in beer using solid phase microextraction (SPME) in combination with a stable isotope dilution assay (SIDA).

PubMed

Steinhaus, Martin; Fritsch, Helge T; Schieberle, Peter

2003-11-19

A stable isotope dilution assay (SIDA) was developed for the quantitation of both linalool enantiomers using synthesized [2H(2)]R/S-linalool as the internal standard. For enrichment of the target compound from beer, a solid phase microextraction method (SPME) was developed. In comparison to the more time-consuming extraction/distillation cleanup of the beer samples, the results obtained by SPME/SIDA were very similar, even under nonequilibration conditions. Analysis of five different types of beer showed significant differences in the linalool concentrations, which were clearly correlated with the intensity of the hoppy aroma note as evaluated by a sensory panel. In addition, significant differences in the R/S ratios were measured in the beers. The SPME/SIDA yielded exact data independently from headspace sampling parameters, such as exposure time or ionic strength of the solution.

Analysis of coffee for the presence of acrylamide by LC-MS/MS.

PubMed

Andrzejewski, Denis; Roach, John A G; Gay, Martha L; Musser, Steven M

2004-04-07

A variety of popular instant, ground, and brewed coffees were analyzed using a modified liquid chromatography-tandem mass spectrometry (LC-MS/MS) method specifically developed for the determination of acrylamide in foods. Coffee test portions were spiked with 13C3-labeled acrylamide as an internal standard prior to their extraction and cleanup. Ground coffees (1 g) and instant coffees (0.5 g) were extracted by shaking with 9 mL of water for 20 min. Brewed coffee test portions (9 mL) were taken through the cleanup procedure without further dilution with extraction solvent. Coffee test portions were cleaned up by passing 1.5 mL first through an Oasis HLB (hydrophilic/lipophilic copolymer sorbent) solid phase extraction (SPE) cartridge and then a Bond Elut-Accucat (cation and anion exchange sorbent) SPE cartridge. The cleaned up extracts were analyzed by positive ion electrospray LC-MS/MS. The MS/MS data was used to detect, confirm, and quantitate acrylamide. The limit of quantitation of the method was 10 ng/g for ground and instant coffees and 1.0 ng/mL for brewed coffee. The levels of acrylamide ranged from 45 to 374 ng/g in unbrewed coffee grounds, from 172 to 539 ng/g in instant coffee crystals, and from 6 to 16 ng/mL in brewed coffee.

Development of sample clean up methods for the analysis of Mycobacterium tuberculosis methyl mycocerosate biomarkers in sputum extracts by gas chromatography–mass spectrometry

PubMed Central

Nicoara, Simona C.; Turner, Nicholas W.; Minnikin, David E.; Lee, Oona Y.-C.; O'Sullivan, Denise M.; McNerney, Ruth; Mutetwa, Reggie; Corbett, Liz E.; Morgan, Geraint H.

2015-01-01

A proof of principle gas chromatography–mass spectrometry method is presented, in combination with clean up assays, aiming to improve the analysis of methyl mycocerosate tuberculosis biomarkers from sputum. Methyl mycocerosates are generated from the transesterification of phthiocerol dimycocerosates (PDIMs), extracted in petroleum ether from sputum of tuberculosis suspect patients. When a high matrix background is present in the sputum extracts, the identification of the chromatographic peaks corresponding to the methyl derivatives of PDIMs analytes may be hindered by the closely eluting methyl ether of cholesterol, usually an abundant matrix constituent frequently present in sputum samples. The purification procedures involving solid phase extraction (SPE) based methods with both commercial Isolute-Florisil cartridges, and purpose designed molecularly imprinted polymeric materials (MIPs), resulted in cleaner chromatograms, while the mycocerosates are still present. The clean-up performed on solutions of PDIMs and cholesterol standards in petroleum ether show that, depending on the solvent mix and on the type of SPE used, the recovery of PDIMs is between 64 and 70%, whilst most of the cholesterol is removed from the system. When applied to petroleum ether extracts from representative sputum samples, the clean-up procedures resulted in recoveries of 36–68% for PDIMs, allowing some superior detection of the target analytes. PMID:25728371

Development and validation of an HPLC-method for determination of free and bound phenolic acids in cereals after solid-phase extraction.

PubMed

Irakli, Maria N; Samanidou, Victoria F; Biliaderis, Costas G; Papadoyannis, Ioannis N

2012-10-01

Whole cereal grains are a good source of phenolic acids associated with reduced risk of chronic diseases. This paper reports the development and validation of a high-performance liquid chromatography-diode array detection (HPLC-DAD) method for the determination of phenolic acids in cereals in either free or bound form. Extraction of free phenolic acids and clean-up was performed by an optimised solid-phase extraction (SPE) protocol on Oasis HLB cartridges using aqueous methanol as eluant. The mean recovery of analytes ranged between 84% and 106%. Bound phenolic acids were extracted using alkaline hydrolysis with mean recoveries of 80-95%, except for gallic acid, caffeic acid and protocatechuic acid. Both free and bound phenolic extracts were separated on a Nucleosil 100 C18 column, 5 μm (250 mm × 4.6 mm) thermostated at 30 °C, using a linear gradient elution system consisting of 1% (v/v) acetic acid in methanol. Method validation was performed by means of linearity, accuracy, intra-day and inter-day precision and sensitivity. Detection limits ranged between 0.13 and 0.18 μg/g. The method was applied to the analysis of free and bound phenolic acids contents in durum wheat, bread wheat, barley, oat, rice, rye, corn and triticale. Copyright © 2012 Elsevier Ltd. All rights reserved.

Multiclass method for the quantification of 92 veterinary antimicrobial drugs in livestock excreta, wastewater, and surface water by liquid chromatography with tandem mass spectrometry.

PubMed

Gao, Jinfang; Cui, Yonghui; Tao, Yanfei; Huang, Lingli; Peng, Dapeng; Xie, Shuyu; Wang, Xu; Liu, Zhenli; Chen, Dongmei; Yuan, Zonghui

2016-11-01

A simple multiresidue method was developed for detecting and quantifying 92 veterinary antimicrobial drugs from eight classes (β-lactams, quinolones, sulfonamides, tetracyclines, lincomycins, macrolides, chloramphenicols, and pleuromutilin) in livestock excreta and water by liquid chromatography with tandem mass spectrometry. The feces samples were extracted by ultrasound-assisted extraction with a mixture of acetonitrile/water (80:20, v/v) and edetate disodium, followed by a cleanup using solid-phase extraction with an amino cartridge. Water samples were purified with hydrophilic-lipophilic balance solid-phase extraction column. Urine samples were extracted with acetonitrile and edetate disodium. Detection of veterinary antimicrobial drugs was achieved by liquid chromatography with tandem mass spectrometry using both positive and negative electrospray ionization mode. The recovery values of veterinary antimicrobial drugs in feces, urine, and water samples were 75-99, 85-110, and 85-101% and associated relative standard deviations were less than 15, 10, and 8%, respectively. The limits of quantification in feces, urine, and water samples were 0.5-1, 0.5-1, and 0.01-0.05 μg/L, respectively. This method was applied to determine real samples obtained from local farms and provides reliable quantification and identification results of 92 veterinary antimicrobial drugs in livestock excreta and water. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A bleached-kraft mill effluent fraction causing induction of a fish mixed-function oxygenase enzyme

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burnison, B.K.; Hodson, P.V.; Nuttley, D.J.

1996-09-01

Pulp mill effluents contain a myriad of chemicals that have the potential to cause deleterious effects on aquatic biota in receiving waters. Some of these chemicals evoke an acute lethal response of exposed biota while others evoke sublethal responses. One such sublethal response is the induction of mixed-function oxygenases (MFO) in fish, specifically the CYP1A1 enzyme ethoxy-resorufin-o-deethylase (EROD). Compounds causing MFO induction include congeners of polychlorinated biphenyls (PCBs), dioxins, furans, and polycyclic aromatic hydrocarbons (PAHs). The authors followed the partitioning of the inducing chemicals in pulp mill effluent fractions by Toxicity Identification Evaluation (TIE), or bioassay-driven chemical analysis. This proceduremore » was eventually modified to a more direct technique involving centrifugation, filtration, cleanup procedures, and C{sub 18} solid-phase adsorption. The extracts from the fractionation of two pulp mill effluents after secondary treatment were tested for EROD-inducing activity in a 4-d rainbow trout bioassay. The methanol extracts of particulates/colloids showed significant inducing capacity in Mill A effluent but not in Mill B effluent. The C{sub 18} methanol extracts induced activity from both effluents, with extracts from Mill A causing the greatest response. The particulate/colloidal extract (Mill A) was used as the source material for chemicals which caused EROD induction. The fraction was purified by solid-phase extraction techniques and reverse-phase high-performance liquid chromatography. The majority of the EROD activity was found in the moderately nonpolar region of the chromatogram (K{sub ow} = 4.6 to 5.1).« less

Simultaneous and confirmative detection of multi-residues of β₂-agonists and β-blockers in urine using LC-MS/MS/MS coupled with β-receptor molecular imprinted polymer SPE clean-up.

PubMed

Fan, S; Zou, J H; Miao, H; Zhao, Y F; Chen, H J; Zhao, R; Wu, Y N

2013-01-01

A liquid chromatography-linear ion-trap spectrometry (LC-MS³) method using β-receptor molecular-imprinted polymer (MIP) solid-phase extraction (SPE) as clean-up was developed to determine simultaneously and confirmatively residues of 25 β₂-agonists and 21 β-blockers in urine samples. Urine samples were subjected to enzymatic hydrolysis by β-glucoronidase/arylsulphatase, and then extracted with perchloric acid. Sample clean-up was performed using β-receptor MIP SPE. A Supelco Ascentis® express Rp-Amide column was used to separate the analytes, and MS³ detection used an electrospray ionisation source in positive-ion mode. Recovery studies were carried out using blank urine samples fortified with the 46 analytes at the levels of 0.5, 1.0 and 2.0 μg l⁻¹. Recoveries were obtained ranging from 60.1% to 109.9% with relative standard deviations (RSDs, n = 7) from 0.5% to 19.4%. The limits of detection (LODs) and limits of quantitation (LOQs) of the 46 analytes in urine were 0.02-0.18 and 0.05-0.60 μg l⁻¹, respectively. As a result of the selective clean-up by MIP SPE and MS³ detection of the target drugs, the sensitivity and accuracy of the present method was high enough for monitoring β₂-agonist and β-blocker residues in urine samples. Satisfactory results were obtained in the process of the determination of positive urine samples.

An HPLC method for determination of azadirachtin residues in bovine muscle.

PubMed

Gai, María Nella; Álvarez, Christian; Venegas, Raúl; Morales, Javier

2011-04-01

A high-performance liquid chromatography (HPLC) method for the determination of azadirachtin (A and B) residues in bovine muscle has been developed. Azadirachtin is a neutral triterpene and chemotherapeutic agent effective in controlling some pest flies in horses, stables, horns and fruit. The actual HPLC method uses an isocratic elution and UV detection. Liquid-liquid extraction and solid-phase purification was used for the clean-up of the biological matrix. The chromatographic determination of these components is achieved using a C18 analytical column with water-acetonitrile mixture (27.5:72.5, v/v) as mobile phase, 1 mL/min as flow rate, 45 °C column temperature and UV detector at 215 nm. The azadirachtin peaks are well resolved and free of interference from matrix components. The extraction and analytical method developed in this work allows the quantitation of azadirachtin with precision and accuracy, establishing a lower limit of quantitation of azadirachtin, extracted from the biological matrix.

Determination of chlorinated acid herbicides in vegetation and soil by liquid chromatography/electrospray-tandem mass spectrometry.

PubMed

Schaner, Angela; Konecny, Jaclyn; Luckey, Laura; Hickes, Heidi

2007-01-01

The method presented uses reversed-phase liquid chromatography with negative electrospray ionization and tandem mass spectrometry to analyze 9 chlorinated acid herbicides in soil and vegetation matrixes: clopyralid, dicamba, MCPP, MCPA, 2,4-DP, 2,4-D, triclopyr, 2,4-DB, and picloram. A 20 g portion is extracted with a basic solution and an aliquot acidified and micropartitioned with 3 mL chloroform. Vegetation samples are subjected to an additional cleanup with a mixed-mode anion exchange solid-phase extraction cartridge. Two precursor product ion transitions per analyte are measured and evaluated to provide the maximum degree of confidence in results. Average recoveries for 3 different soil types tested ranged from 72 to 107% for all compounds with the exception of 2,4-DB at 56-99%. Average recoveries for the 3 different vegetation types studied were lower and ranged from 53 to 80% for all compounds.

Critical comparison of the on-line and off-line molecularly imprinted solid-phase extraction of patulin coupled with liquid chromatography.

PubMed

Lhotská, Ivona; Holznerová, Anežka; Solich, Petr; Šatínský, Dalibor

2017-12-01

Reaching trace amounts of mycotoxin contamination requires sensitive and selective analytical tools for their determination. Improving the selectivity of sample pretreatment steps covering new and modern extraction techniques is one way to achieve it. Molecularly imprinted polymers as selective sorbent for extraction undoubtedly meet these criteria. The presented work is focused on the hyphenation of on-line molecularly imprinted solid-phase extraction with a chromatography system using a column-switching approach. Making a critical comparison with a simultaneously developed off-line extraction procedure, evaluation of pros and cons of each method, and determining the reliability of both methods on a real sample analysis were carried out. Both high-performance liquid chromatography methods, using off-line extraction on molecularly imprinted polymer and an on-line column-switching approach, were validated, and the validation results were compared against each other. Although automation leads to significant time savings, fewer human errors, and required no handling of toxic solvents, it reached worse detection limits (15 versus 6 μg/L), worse recovery values (68.3-123.5 versus 81.2-109.9%), and worse efficiency throughout the entire clean-up process in comparison with the off-line extraction method. The difficulties encountered, the compromises made during the optimization of on-line coupling and their critical evaluation are presented in detail. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pressurized liquid extraction using water/isopropanol coupled with solid-phase extraction cleanup for industrial and anthropogenic waste-indicator compounds in sediment

USGS Publications Warehouse

Burkhardt, M.R.; ReVello, R.C.; Smith, S.G.; Zaugg, S.D.

2005-01-01

A broad range of organic compounds is recognized as environmentally relevant for their potential adverse effects on human and ecosystem health. This method was developed to better determine the distribution of 61 compounds that are typically associated with industrial and household waste as well as some that are toxic and known (or suspected) for endocrine-disrupting potential extracted from environmental sediment samples. Pressurized liquid extraction (PLE) coupled with solid-phase extraction (SPE) was used to reduce sample preparation time, reduce solvent consumption to one-fifth of that required using dichloromethane-based Soxhlet extraction, and to minimize background interferences for full scan GC/MS analysis. Recoveries from spiked Ottawa sand, commercially available topsoil, and environmental stream sediment, fortified at 4-720 ??g per compound, averaged 76 ?? 13%. Initial method detection limits for single-component compounds ranged from 12.5 to 520 ??g/kg, based on 25 g samples. Results from 103 environmental sediment samples show that 36 out of 61 compounds (59%) were detected in at least one sample with concentrations ranging from 20 to 100,000 ??g/kg. The most frequently detected compound, beta-sitosterol, a plant sterol, was detected in 87 of the 103 (84.5%) environmental samples with a concentration range 360-100,000 ??g/kg. Results for a standard reference material using dichloromethane Soxhlet-based extraction are also compared. ?? 2004 Published by Elsevier B.V.

Determination of acetanilide herbicides in cereal crops using accelerated solvent extraction, solid-phase extraction and gas chromatography-electron capture detector.

PubMed

Zhang, Yaping; Yang, Jun; Shi, Ronghua; Su, Qingde; Yao, Li; Li, Panpan

2011-07-01

A method was developed to determine eight acetanilide herbicides from cereal crops based on accelerated solvent extraction (ASE) and solid-phase extraction (SPE) followed by gas chromatography-electron capture detector (GC-ECD) analysis. During the ASE process, the effect of four parameters (temperature, static time, static cycles and solvent) on the extraction efficiency was considered and compared with shake-flask extraction method. After extraction with ASE, four SPE tubes (graphitic carbon black/primary secondary amine (GCB/PSA), GCB, Florisil and alumina-N) were assayed for comparison to obtain the best clean-up efficiency. The results show that GCB/PSA cartridge gave the best recoveries and cleanest chromatograms. The analytical process was validated by the analysis of spiked blank samples. Performance characteristics such as linearity, limit of detection (LOD), limit of quantitation (LOQ), precision and recovery were studied. At 0.05 mg/kg spiked level, recoveries and precision values for rice, wheat and maize were 82.3-115.8 and 1.1-13.6%, respectively. For all the herbicides, LOD and LOQ ranged from 0.8 to 1.7 μg/kg and from 2.4 to 5.3 μg/kg, respectively. The proposed analytical methodology was applied for the analysis of the targets in samples; only three herbicides, propyzamid, metolachlor and diflufenican, were detected in two samples. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Attractive design: an elution solvent optimization platform for magnetic-bead-based fractionation using digital microfluidics and design of experiments.

PubMed

Lafrenière, Nelson M; Mudrik, Jared M; Ng, Alphonsus H C; Seale, Brendon; Spooner, Neil; Wheeler, Aaron R

2015-04-07

There is great interest in the development of integrated tools allowing for miniaturized sample processing, including solid phase extraction (SPE). We introduce a new format for microfluidic SPE relying on C18-functionalized magnetic beads that can be manipulated in droplets in a digital microfluidic platform. This format provides the opportunity to tune the amount (and potentially the type) of stationary phase on-the-fly, and allows the removal of beads after the extraction (to enable other operations in same device-space), maintaining device reconfigurability. Using the new method, we employed a design of experiments (DOE) operation to enable automated on-chip optimization of elution solvent composition for reversed phase SPE of a model system. Further, conditions were selected to enable on-chip fractionation of multiple analytes. Finally, the method was demonstrated to be useful for online cleanup of extracts from dried blood spot (DBS) samples. We anticipate this combination of features will prove useful for separating a wide range of analytes, from small molecules to peptides, from complex matrices.

Pungency Quantitation of Hot Pepper Sauces Using HPLC

NASA Astrophysics Data System (ADS)

Betts, Thomas A.

1999-02-01

A class of compounds known as capsaicinoids are responsible for the "heat" of hot peppers. To determine the pungency of a particular pepper or pepper product, one may quantify the capsaicinoids and relate those concentrations to the perceived heat. The format of the laboratory described here allows students to collectively develop an HPLC method for the quantitation of the two predominant capsaicinoids (capsaicin and dihydrocapsaicin) in hot-pepper products. Each small group of students investigated one of the following aspects of the method: detector wavelength, mobile-phase composition, extraction of capsaicinoids, calibration, and quantitation. The format of the lab forced students to communicate and cooperate to develop this method. The resulting HPLC method involves extraction with acetonitrile followed by solid-phase extraction clean-up, an isocratic 80:20 methanol-water mobile phase, a 4.6 mm by 25 cm C-18 column, and UV absorbance detection at 284 nm. The method developed by the students was then applied to the quantitation of capsaicinoids in a variety of hot pepper sauces. Editor's Note on Hazards in our April 2000 issue addresses the above.

A Rapid Method for the Quantitative Determination of 34 Pesticides in Nonalcoholic Carbonated Beverages Using Liquid-Liquid Extraction Coupled to Dispersive Solid-Phase Cleanup Followed by Gas Chromatography with Tandem Mass Spectrometry.

PubMed

Rai, Satyajeet; Gullapalli, Madhuri Devi; Srivastava, Anshuman; Shaik, Hussain; Siddiqui, Mohammed Haris; Mudiam, Mohana Krishna Reddy

2017-05-01

An economical, rapid, and sensitive multiresidue method using liquid-liquid extraction (LLE) coupled with dispersive SPE (dSPE) cleanup was developed for the quantitative determination of 34 multiclass multiresidue (MCMR) pesticides (14 organochlorines, eight organophosphates, 10 synthetic pyrethroids, and two herbicides) in nonalcoholic carbonated beverages (cola, orange, lemon-lime, and citra) using GC with tandem MS. The procedure mainly involved LLE by dichloromethane and dSPE cleanup in the presence of magnesium sulfate, primary secondary amine, and C18. The RSD of the developed method was found to be less than 14%. The LOD and LOQ values for all the analyzed pesticides were found in the ranges of 0.001-0.027 μg/L and 0.004-0.088 μg/L, respectively. The LOQ levels of the pesticides analyzed were found to be well below the recommended limit by the European Union (0.1 μg/L in water). The mean recoveries of pesticides in different nonalcoholic carbonated beverages (cola, orange, lemon-lime, and citra) were found to be in the range of 79-111%, with RSDs less than 11%. The validation data prove that the method can be acceptable to regulatory agencies for the routine analysis of MCMR pesticides in nonalcoholic carbonated beverages.

Recent Modifications and Validation of QuEChERS-dSPE Coupled to LC-MS and GC-MS Instruments for Determination of Pesticide/Agrochemical Residues in Fruits and Vegetables: Review.

PubMed

Lawal, Abubakar; Wong, Richard Chee Seng; Tan, Guan Huat; Abdulra'uf, Lukman Bola; Alsharif, Ali Mohamed Ali

2018-04-21

Fruits and vegetables constitute a major type of food consumed daily apart from whole grains. Unfortunately, the residual deposits of pesticides in these products are becoming a major health concern for human consumption. Consequently, the outcome of the long-term accumulation of pesticide residues has posed many health issues to both humans and animals in the environment. However, the residues have previously been determined using conventionally known techniques, which include liquid-liquid extraction, solid-phase extraction (SPE) and the recently used liquid-phase microextraction techniques. Despite the positive technological effects of these methods, their limitations include; time-consuming, operational difficulty, use of toxic organic solvents, low selective property and expensive extraction setups, with shorter lifespan of instrumental performances. Thus, the potential and maximum use of these methods for pesticides residue determination has resulted in the urgent need for better techniques that will overcome the highlighted drawbacks. Alternatively, attention has been drawn recently towards the use of quick, easy, cheap, effective, rugged and safe technique (QuEChERS) coupled with dispersive solid-phase extraction (dSPE) to overcome the setback challenges experienced by the previous technologies. Conclusively, the reviewed QuEChERS-dSPE techniques and the recent cleanup modifications justifiably prove to be reliable for routine determination and monitoring the concentration levels of pesticide residues using advanced instruments such as high-performance liquid chromatography, liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry.

Comparison of methods and optimisation of the analysis of fumonisins B₁ and B₂ in masa flour, an alkaline cooked corn product.

PubMed

De Girolamo, A; Pascale, M; Visconti, A

2011-05-01

A comparison study of different extraction and clean-up procedures for the liquid chromatographic analysis of fumonisins B(1) (FB(1)) and B(2) (FB(2)) in corn masa flour was performed. The procedures included extraction (heat or room temperature) with acidic conditions or EDTA-containing solvents, and clean-up by immunoaffinity or C18 solid-phase extraction columns. Thereafter an analytical method was optimised using extraction with an acidic mixture of methanol-acetonitrile-citrate/phosphate buffer, clean-up through the immunoaffinity column and determination of fumonisins by liquid chromatography with automated pre-column derivatisation with o-phthaldialdehyde reagent. Recovery experiments performed on yellow, white and blue masa flours at spiking levels of 400, 800 and 1200 µg kg(-1) FB(1) and of 100, 200 and 300 µg kg(-1) FB(2) gave overall mean recoveries of 99% (±6%) for FB(1) and 88% (±6%) for FB(2). Good recoveries (higher than 90% for both FB(1) and FB(2)) were also obtained with corn tortilla chips. The limits of quantification of the method (signal-to-noise ratio of 10) were 25 µg kg(-1) for FB(1) and 17 µg kg(-1) for FB(2). The method was tested on different commercial corn masa flours as well as on white and yellow corn tortilla chips, showing fumonisin contamination levels (FB(1) + FB(2)) up to 1800 µg kg(-1) (FB(1) + FB(2)) in masa flour and 960 µg kg(-1) in tortilla chips. Over 30% of masa flours originating from Mexico exceeded the European Union maximum permitted level.

Determination of organophosphorus pesticides in bovine tissue by an on-line coupled matrix solid-phase dispersion-solid phase extraction-high performance liquid chromatography with diode array detection method.

PubMed

Gutiérrez Valencia, Tania M; García de Llasera, Martha P

2011-09-28

A miniaturized method based on matrix solid-phase dispersion coupled to solid phase extraction and high performance liquid chromatography with diode array detection (MSPD-SPE-HPLC/DAD) was developed for the trace simultaneous determination of the following organophosphorus pesticides (OPPs) in bovine tissue: parathion-methyl, fenitrothion, parathion, chlorfenvinphos, diazinon, ethion, fenchlorphos, chlorpyrifos and carbophenothion. To perform the coupling between MSPD and SPE, 0.05 g of sample was dispersed with 0.2 g of C(18) silica sorbent and packed into a stainless steel cartridge containing 0.05 g of silica gel in the bottom. After a clean-up of high and medium polarity interferences with water and an acetonitrile:water mixture, the OPPs were desorbed from the MSPD cartridge with pure acetonitrile and directly transferred to a dynamic mixing chamber for dilution with water and preconcentration into an SPE 20 mm × 2.0 mm I.D. C(18) silica column. Subsequently, the OPPs were eluted on-line with the chromatographic mobile phase to the analytical column and the diode array detector for their separation and detection, respectively. The method was validated and yielded recovery values between 91% and 101% and precision values, expressed as relative standard deviations (RSD), which were less than or equal to 12%. Linearity was good and ranged from 0.5 to 10 μg g(-1), and the limits of detection of the OPPs were in the range of 0.04-0.25 μg g(-1). The method was satisfactorily applied to the analysis of real samples and is recommended for food control, research efforts when sample amounts are limited, and laboratories that have ordinary chromatographic instrumentation. Copyright © 2011 Elsevier B.V. All rights reserved.

Alternative sorbents for the dispersive solid-phase extraction step in quick, easy, cheap, effective, rugged and safe method for extraction of pesticides from rice paddy soils with determination by liquid chromatography tandem mass spectrometry.

PubMed

Arias, Jean Lucas de Oliveira; Rombaldi, Caroline; Caldas, Sergiane Souza; Primel, Ednei Gilberto

2014-09-19

The clean-up step is essential to reduce interferences, improve quantification and help to maintain the integrity of the chromatographic system when working with complex matrices. In this study, alternative materials were evaluated as sorbents in the dispersive solid-phase extraction (D-SPE) for the determination and extraction of seventeen pesticides from rice paddy soil samples by the quick, easy, cheap, effective, rugged and safe (QuEChERS) method coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Chitin, chitosan, diatomaceous earth and PSA were compared in terms of extraction efficiency and matrix effect. The best results were achieved when chitosan was used. Quantification limits ranged from 0.1 to 100μgkg(-1). Calibration curves showed correlation coefficient values higher than 0.98. Results of accuracy and precision in the spiked soil samples between 60% and 120%, with a relative standard deviation lower than 20%, were reached for 15 out of 17 pesticides. The matrix effect was evaluated and only one compound was influenced by the matrix components, showing medium effect. Results showed that alternative materials are more effective and less expensive than traditional sorbents which have been usually employed, i.e., they may be used in the D-SPE step during the extraction of pesticides from rice paddy soils. Copyright © 2014 Elsevier B.V. All rights reserved.

Development and validation of a quantitative UHPLC-MS/MS method for selected brominated flame retardants in food.

PubMed

Malysheva, Svetlana V; Goscinny, Séverine; Malarvannan, Govindan; Poma, Giulia; Andjelkovic, Mirjana; Voorspoels, Stefan; Covaci, Adrian; Van Loco, Joris

2018-02-01

An ultra-high performance liquid chromatography - tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated (in-house) for the quantification of selected brominated flame retardants (BFRs), including tetrabromobisphenol A (TBBPA), hexabromocyclododecanes (HBCDs), tetrabromobisphenol S (TBBPS) and bromophenols (BPs), in various food matrices. The sample preparation consisted of extraction of TBBPS with acidified acetonitrile followed by a fast dispersive solid-phase extraction (dSPE) clean-up and extraction of the other BFRs with a mixture of hexane and dichloromethane (1:1, v/v) with subsequent clean-up using acidified silica (44%, w/w). The limits of quantification of the method varied widely for the types of food matrices and the different classes of BFRs from 4 pg g -1 wet weight (ww) to 8 ng g -1 ww. For most of the analytes the apparent recovery was in the range 70-120%, and the method precision (under repeatability conditions) was below 20%. The method was successfully applied in proficiency testing exercises as well as for analysis of various food items. Only 25% of the collected food samples contained BFRs, with 4-bromophenol and α-HBCD as the only detected compounds. The contaminated foodstuffs were fish and eggs with concentrations in the range from 48 to 305 pg g -1 ww.

Analysis of perfluorinated carboxylic acids in soils II: optimization of chromatography and extraction.

PubMed

Washington, John W; Henderson, W Matthew; Ellington, J Jackson; Jenkins, Thomas M; Evans, John J

2008-02-15

With the objective of detecting and quantitating low concentrations of perfluorinated carboxylic acids (PFCAs), including perfluorooctanoic acid (PFOA), in soils, we compared the analytical suitability of liquid chromatography columns containing three different stationary phases, two different liquid chromatography-tandem mass spectrometry (LC/MS/MS) systems, and eight combinations of sample-extract pretreatments, extractions and cleanups on three test soils. For the columns and systems we tested, we achieved the greatest analytical sensitivity for PFCAs using a column with a C(18) stationary phase in a Waters LC/MS/MS. In this system we achieved an instrument detection limit for PFOA of 270 ag/microL, equating to about 14 fg of PFOA on-column. While an elementary acetonitrile/water extraction of soils recovers PFCAs effectively, natural soil organic matter also dissolved in the extracts commonly imparts significant noise that appears as broad, multi-nodal, asymmetric peaks that coelute with several PFCAs. The intensity and elution profile of this noise is highly variable among soils and it challenges detection of low concentrations of PFCAs by decreasing the signal-to-noise contrast. In an effort to decrease this background noise, we investigated several methods of pretreatment, extraction and cleanup, in a variety of combinations, that used alkaline and unbuffered water, acetonitrile, tetrabutylammonium hydrogen sulfate, methyl-tert-butyl ether, dispersed activated carbon and solid-phase extraction. For the combined objectives of complete recovery and minimization of background noise, we have chosen: (1) alkaline pretreatment; (2) extraction with acetonitrile/water; (3) evaporation to dryness; (4) reconstitution with tetrabutylammonium-hydrogen-sulfate ion-pairing solution; (5) ion-pair extraction to methyl-tert-butyl ether; (6) evaporation to dryness; (7) reconstitution with 60/40 acetonitrile/water (v/v); and (8) analysis by LC/MS/MS. Using this method, we detected in all three of our test soils, endogenous concentrations of all of our PFCA analytes, C(6) through C(10)-the lowest concentrations being roughly 30 pg/g of dry soil for perfluorinated hexanoic and decanoic acids in an agricultural soil.

A novel method for analysing key corticosteroids in polar bear (Ursus maritimus) hair using liquid chromatography tandem mass spectrometry.

PubMed

Weisser, Johan J; Hansen, Martin; Björklund, Erland; Sonne, Christian; Dietz, Rune; Styrishave, Bjarne

2016-04-01

This paper presents the development and evaluation of a methodology for extraction, clean-up and analysis of three key corticosteroids (aldosterone, cortisol and corticosterone) in polar bear hair. Such a methodology can be used to monitor stress biomarkers in polar bears and may provide as a useful tool for long-term and retrospective information. We developed a combined pressurized liquid extraction (PLE)-solid phase extraction (SPE) procedure for corticosteroid extraction and clean-up followed by high pressure liquid chromatography tandem mass spectrometry (HPLC-MS/MS) analysis. This procedure allows for the simultaneous determination of multiple steroids, which is in contrast to previous polar bear studies based on ELISA techniques. Absolute method recoveries were 81%, 75% and 60% for cortisol, corticosterone and aldosterone, respectively. We applied the developed method on a hair sample pooled from four East Greenland polar bears. Herein cortisol and corticosterone were successfully determined in levels of 0.32±0.02ng/g hair and 0.13±0.02ng/g hair, respectively. Aldosterone was below limit of detection (LOD<0.17ng/g). The cortisol hair concentration found in these East Greenland polar bears was consistent with cortisol levels previously determined in the Southern Hudson Bay and James Bay in Canada using ELISA kits. Copyright © 2016 Elsevier B.V. All rights reserved.

Large-scale pesticide testing in olives by liquid chromatography-electrospray tandem mass spectrometry using two sample preparation methods based on matrix solid-phase dispersion and QuEChERS.

PubMed

Gilbert-López, Bienvenida; García-Reyes, Juan F; Lozano, Ana; Fernández-Alba, Amadeo R; Molina-Díaz, Antonio

2010-09-24

In this work we have evaluated the performance of two sample preparation methodologies for the large-scale multiresidue analysis of pesticides in olives using liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS). The tested sample treatment methodologies were: (1) liquid-liquid partitioning with acetonitrile followed by dispersive solid-phase extraction clean-up using GCB, PSA and C18 sorbents (QuEChERS method - modified for fatty vegetables) and (2) matrix solid-phase dispersion (MSPD) using aminopropyl as sorbent material and a final clean-up performed in the elution step using Florisil. An LC-MS/MS method covering 104 multiclass pesticides was developed to examine the performance of these two protocols. The separation of the compounds from the olive extracts was achieved using a short C18 column (50 mm x 4.6 mm i.d.) with 1.8 microm particle size. The identification and confirmation of the compounds was based on retention time matching along with the presence (and ratio) of two typical MRM transitions. Limits of detection obtained were lower than 10 microgkg(-1) for 89% analytes using both sample treatment protocols. Recoveries studies performed on olives samples spiked at two concentration levels (10 and 100 microgkg(-1)) yielded average recoveries in the range 70-120% for most analytes when QuEChERS procedure is employed. When MSPD was the choice for sample extraction, recoveries obtained were in the range 50-70% for most of target compounds. The proposed methods were successfully applied to the analysis of real olives samples, revealing the presence of some of the target species in the microgkg(-1) range. Besides the evaluation of the sample preparation approaches, we also discuss the use of advanced software features associated to MRM method development that overcome several limitations and drawbacks associated to MS/MS methods (time segments boundaries, tedious method development/manual scheduling and acquisition limitations). This software feature recently offered by different vendors is based on an algorithm that associates retention time data for each individual MS/MS transition, so that the number of simultaneously traced transitions throughout the entire chromatographic run (dwell times and sensitivity) is maximized. Copyright 2010 Elsevier B.V. All rights reserved.

Magnetic Solid Phase Extraction Based on Oleic Acid Coated Fe3O4 for the Determination of Benzo[α]pyrene in Cigarette Smoke Coupled with High-Performance Liquid Chromatography.

PubMed

Feng, Shouai; Wei, Kang; Tian, Zhaofu; Li, Xiaolan; Meng, Dongling; Liao, Wenlong; Miao, Mingming; Yang, Yaling

2016-07-29

In this work, a simple and effective method based on magnetic solid-phase extraction combined with high-performance liquid chromatography was developed for the determination of benzo[α]pyrene (BaP) in cigarette smoke. Oleic acid coated Fe 3 O 4 (Fe 3 O 4 -OA) was synthesized and directly used as an efficient sorbent for the first time in magnetic solid-phase extraction (MSPE) procedure for the clean-up of BaP in cigarette smoke extracts. The synthesized Fe 3 O 4 -OA was characterized by transmission electron microscopy, X-ray diffraction and Fourier transformed infrared spectroscopy. The extraction via Fe 3 O 4 -OA was dispersed in the extracts of cigarette smoke followed by the magnetic isolation, acetonitrile-tetrahydrofuran (ACN-THF; v/v = 9:1) was used for desorption of the analyte. The effects of important parameters such as the amount of adsorbent, solution pH, the content of acetonitrile, temperature and sorption time were investigated. The method showed good linearity for the determination of BaP in the concentration range of 0.5-50 ng mL -1 with a regression coefficient (R 2 ) of 0.9987. The limit of detection and limit of quantification for BaP were obtained to be 0.12 and 0.41 ng mL -1 , respectively. The mean recoveries were in the range from 81.0% to 97.6% at low, medium, high spiked levels, and the relative standard deviations were in the range of 2.7-6.8%. Combined with high-performance liquid chromatography and fluorescence detection, a simple and effective method was developed for the analysis of BaP in cigarette smoke. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Simultaneous determination of multiclass pesticide residues in human plasma using a mini QuEChERS method.

PubMed

Srivastava, Anshuman; Rai, Satyajeet; Kumar Sonker, Ashish; Karsauliya, Kajal; Pandey, Chandra Prabha; Singh, Sheelendra Pratap

2017-06-01

Blood is one of the most assessable matrices for the determination of pesticide residue exposure in humans. Effective sample preparation/cleanup of biological samples is very important in the development of a sensitive, reproducible, and robust method. In the present study, a simple, cost-effective, and rapid gas chromatography-tandem mass spectrometry method has been developed and validated for simultaneous analysis of 31 multiclass (organophosphates, organochlorines, and synthetic pyrethroids) pesticide residues in human plasma by means of a mini QuEChERS (quick, easy, cheap, effective, rugged, and safe) method. We have adopted a modified version of the QuEChERS method, which is primarily used for pesticide residue analysis in food commodities. The QuEChERS method was optimized by use of different extraction solvents and different amounts and combinations of salts and sorbents (primary-secondary amines and C 18 ) for the dispersive solid-phase extraction step. The results show that a combination of ethyl acetate with 2% acetic acid, magnesium sulfate (0.4 g), and solid-phase extraction for sample cleanup with primary-secondary amines (50 mg) per 1-mL volume of plasma is the most suitable for generating acceptable results with high recoveries for all multiclass pesticides from human plasma. The mean recovery ranged from 74% to 109% for all the analytes. The limit of quantification and limit of detection of the method ranged from 0.12 to 13.53 ng mL -1 and from 0.04 to 4.10 ng mL -1 respectively. The intraday precision and the interday precision of the method were 6% or less and 11% or less respectively. This method would be useful for the analysis of a wide range of pesticides of interest in a small volume of clinical and/or forensic samples to support biomonitoring and toxicological applications. Graphical Abstract Pesticide residues analysis in human plasma using mini QuEChERS method.

MSPD procedure for determining buprofezin, tetradifon, vinclozolin, and bifenthrin residues in propolis by gas chromatography-mass spectrometry.

PubMed

dos Santos, Thaíse Fernanda Santana; Aquino, Adriano; Dórea, Haroldo Silveira; Navickiene, Sandro

2008-03-01

A simple and effective extraction method based on matrix solid-phase dispersion (MSPD) was developed to determine bifenthrin, buprofezin, tetradifon, and vinclozolin in propolis using gas chromatography-mass spectrometry in selected ion monitoring mode (GC-MS, SIM). Different method conditions were evaluated, for example type of solid phase (C(18), alumina, silica, and Florisil), the amount of solid phase and eluent (n-hexane, dichloromethane, dichloromethane-n-hexane (8:2 and 1:1, v/v) and dichloromethane-ethyl acetate (9:1, 8:2 and 7:3, v/v)). The best results were obtained using 0.5 g propolis, 1.0 g silica as dispersant sorbent, 1.0 g Florisil as clean-up sorbent, and dichloromethane-ethyl acetate (9:1, v/v) as eluting solvent. The method was validated by analysis of propolis samples fortified at different concentration levels (0.25 to 1.0 mg kg(-1)). Average recoveries (four replicates) ranged from 67% to 175% with relative standard deviation between 5.6% and 12.1%. Detection and quantification limits ranged from 0.05 to 0.10 mg kg(-1) and 0.15 to 0.25 mg kg(-1) propolis, respectively.

[Determination of paraquat and diquat in drinking water and environmental water by high performance liquid chromatography coupled with on-line clean-up and solid phase extraction].

PubMed

Chen, Jing; Liu, Zhaojin; An, Baochao; Lu, Yan; Xu, Qun

2012-10-01

An on-line solid phase extraction (SPE) system was used to eliminate the interferences sufficiently and fulfill the simple and sensitive determination of diquat and paraquat in tap and pond water. This on-line SPE system used two SPE cartridges. One was an Acclaim Mixed-Mode WAX-1 cartridge for the elimination of anionic interferences; the other one was an Acclaim Mixed-Mode WCX-1 cartridge for the enrichment of diquat and paraquat and the elimination of co-enriched cationic interferences. The baseline separation of diquat and paraquat was achieved on an Acclaim Trinity P1 column. A dual-gradient high performance liquid chromatographic (HPLC) system provided an efficient platform to fulfill the on-line SPE and separation, and the system operated under automatic control of chromatography data system software. The complete analysis only required 16 min, and the detection limits of the method were 0.12 microg/L for diquat and 0.10 microg/L for paraquat. The method is simple, rapid and sensitive, and can be applied to the determination of diquat and paraquat in drinking water and environmental water.

Analytical strategies for organic food packaging contaminants.

PubMed

Sanchis, Yovana; Yusà, Vicent; Coscollà, Clara

2017-03-24

In this review, we present current approaches in the analysis of food-packaging contaminants. Gas and liquid chromatography coupled to mass spectrometry detection have been widely used in the analysis of some relevant families of these compounds such as primary aromatic amines, bisphenol A, bisphenol A diglycidyl ether and related compounds, UV-ink photoinitiators, perfluorinated compounds, phthalates and non-intentionally added substances. Main applications for sample treatment and different types of food-contact material migration studies have been also discussed. Pressurized Liquid Extraction, Solid-Phase Microextraction, Focused Ultrasound Solid-Liquid Extraction and Quechers have been mainly used in the extraction of food contact material (FCM) contaminants, due to the trend of minimising solvent consumption, automatization of sample preparation and integration of extraction and clean-up steps. Recent advances in analytical methodologies have allowed unequivocal identification and confirmation of these contaminants using Liquid Chromatography coupled to High Resolution Mass Spectrometry (LC-HRMS) through mass accuracy and isotopic pattern applying. LC-HRMS has been used in the target analysis of primary aromatic amines in different plastic materials, but few studies have been carried out applying this technique in post-target and non-target analysis of FCM contaminants. Copyright © 2017 Elsevier B.V. All rights reserved.

Determination of polychlorinated biphenyls in fish: optimisation and validation of a method based on accelerated solvent extraction and gas chromatography-mass spectrometry.

PubMed

Ottonello, Giuliana; Ferrari, Angelo; Magi, Emanuele

2014-01-01

A simple and robust method for the determination of 18 polychlorinated biphenyls (PCBs) in fish was developed and validated. A mixture of acetone/n-hexane (1:1, v/v) was selected for accelerated solvent extraction (ASE). After the digestion of fat, the clean-up was carried out using solid phase extraction silica cartridges. Samples were analysed by GC-MS in selected ion monitoring (SIM) using three fragment ions for each congener (one quantifier and two qualifiers). PCB 155 and PCB 198 were employed as internal standards. The lowest limit of detection was observed for PCB 28 (0.4ng/g lipid weight). The accuracy of the method was verified by means of the Certified Reference Material EDF-2525 and good results in terms of linearity (R(2)>0.994) and recoveries (80-110%) were also achieved. Precision was evaluated by spiking blank samples at 4, 8 and 12ng/g. Relative standard deviation values for repeatability and reproducibility were lower than 8% and 16%, respectively. The method was applied to the determination of PCBs in 80 samples belonging to four Mediterranean fish species. The proposed procedure is particularly effective because it provides good recoveries with lowered extraction time and solvent consumption; in fact, the total time of extraction is about 12min per sample and, for the clean-up step, a total solvent volume of 13ml is required. Copyright © 2013 Elsevier Ltd. All rights reserved.

Simultaneously determination of bisphenol A and its alternatives in sediment by ultrasound-assisted and solid phase extractions followed by derivatization using GC-MS.

PubMed

Wang, Qiang; Zhu, Lingyan; Chen, Meng; Ma, Xinxin; Wang, Xiaolei; Xia, Junchao

2017-02-01

Bisphenol analogues are a group of chemicals which are being widely applied in industrial and household products owing to regulations on bisphenol A (BPA) in many countries. In this study, an analytical method, including extraction from complex environmental matrices, clean-up using solid phase extraction (SPE) and following-up derivatization prior to gas chromatography coupled with mass spectrometry (GC-MS), was developed to analyze seven commonly used bisphenols in sediment. Five kinds of extraction solvents, four kinds of SPE cartridges, and four kinds of SPE eluting solvents were individually tested for their performances; and the conditions for derivatizing were also optimized. Finally, C 18 cartridge was determined as the SPE cartridge and methanol was selected as extracting and eluting solvent. Acetic anhydride (AA) was used as derivatizing agent and reaction took 20 min at room temperature. The method was used successfully to measure the seven bisphenol compounds in sediment samples from Taihu Lake, China. BPA, bisphenol F and bisphenol S were detected in all sediment samples, with concentrations in the range of 3.94-33.2; 0.503-3.28 and 0.323-27.3 ng g -1 dw. Other compounds were detected at low frequencies or not detected. We provided a convenient, reliable, and sensitive method to analyze bisphenol compounds in complex environmental samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

Computational and experimental investigation of molecular imprinted polymers for selective extraction of dimethoate and its metabolite omethoate from olive oil.

PubMed

Bakas, Idriss; Oujji, Najwa Ben; Moczko, Ewa; Istamboulie, Georges; Piletsky, Sergey; Piletska, Elena; Ait-Addi, Elhabib; Ait-Ichou, Ihya; Noguer, Thierry; Rouillon, Régis

2013-01-25

This work presents the development of molecularly imprinted polymers (MIPs) for the selective extraction of dimethoate from olive oil. Computational simulations allowed selecting itaconic acid as the monomer showing the highest affinity towards dimethoate. Experimental validation confirmed modelling predictions and showed that the polymer based on IA as functional monomer and omethoate as template molecule displays the highest selectivity for the structurally similar pesticides dimethoate, omethoate and monocrotophos. Molecularly imprinted solid phase extraction (MISPE) method was developed and applied to the clean-up of olive oil extracts. It was found that the most suitable solvents for loading, washing and elution step were respectively hexane, hexane-dichloromethane (85:15%) and methanol. The developed MIPSE was successfully applied to extraction of dimethoate from olive oil, with recovery rates up to 94%. The limits of detection and quantification of the described method were respectively 0.012 and 0.05 μg g(-1). Copyright © 2012 Elsevier B.V. All rights reserved.

A fast and sensitive method for the simultaneous analysis of a wide range of per- and polyfluoroalkyl substances in indoor dust using on-line solid phase extraction-ultrahigh performance liquid chromatography-time-of-flight-mass spectrometry.

PubMed

Padilla-Sánchez, Juan Antonio; Haug, Line Småstuen

2016-05-06

A fast and sensitive method for simultaneous determination of 18 traditional and 6 alternative per- and polyfluoroalkyl substances (PFASs) using solid-liquid extraction (SLE), off-line clean-up using activated carbon and on-line solid phase extraction-ultrahigh performance liquid chromatography-time-of-flight-mass spectrometry (on-line SPE-UHPLC-TOF-MS) was developed. The extraction efficiency was studied and recoveries in range the 58-114% were obtained. Extraction and injection volumes were also optimized to 2mL and 400μL, respectively. The method was validated by spiking dust from a vacuum cleaner bag that had been found to contain low levels of the PFASs in focus. Low method detection limits (MDLs) and method quantification limits (MQLs) in the range 0.008-0.846ngg(-1) and 0.027-2.820ngg(-1) were obtained, respectively. For most of the PFASs, the accuracies were between 70 and 125% in the range from 2 to100ngg(-1) dust. Intra-day and inter-day precisions were in general well below 30%. Analysis of a Standard Reference Material (SRM 2585) showed high accordance with results obtained by other laboratories. Finally, the method was applied to seven indoor dust samples, and PFAS concentrations in the range 0.02-132ngg(-1) were found. The highest median concentrations were observed for some of the alternative PFASs, such as 6:2-diPAP (25ngg(-1)), 8:2-diPAP (49ngg(-1)), and PFOPA (23ngg(-1)), illustrating the importance of inclusion of new PFASs in the analytical methods. Copyright © 2016 Elsevier B.V. All rights reserved.

Multiresidue method for the determination of 227 pesticides in hot pepper (Capsicum annuum L.) by liquid chromatography with tandem mass spectrometry.

PubMed

Zhu, Yong-Zhe; Zhao, Mei-Ai; Nan Feng, Ya; Han Kim, Jeong

2014-10-01

A high-throughput, rapid, and efficient modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method with a simple cleanup procedure has been developed for simultaneously determining 227 pesticides in pepper samples by liquid chromatography with tandem mass spectrometry (running time: 10 min). Pesticide residues were extracted/partitioned with an acetonitrile/DisQuE QuEChERS pouch, and the resulting samples were cleaned up with different methods: dispersive solid-phase extraction with primary secondary amines or multiwalled carbon nanotubes and graphitized carbon solid mini cartridge column. The results indicated that multiwalled carbon nanotubes dispersive sorbents achieved the best recoveries and had less matrix interference. The numbers of pesticides with a recovery in the range of 70-120% were 199 at a spiked level of 40 μg/kg. The correlation coefficients (r(2)) for 227 pesticides were above 0.99, while the limits of quantitation of pesticides in pepper samples ranged from 0.13 to 13.51 μg/kg (S/N = 10), and the limits of detection ranged from 0.04 to 4.05 μg/kg (S/N = 3). The relative standard deviations of approximately 197 pesticides were below 20% at spiked levels of 40 μg/kg. Based on these results, the proposed method was chosen as the most suitable cleanup procedure for the determination of multiresidue pesticides in pepper samples. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparison study of two procedures for the determination of emamectin benzoate in medicated fish feed.

PubMed

Farer, Leslie J; Hayes, John M

2005-01-01

A new method has been developed for the determination of emamectin benzoate in fish feed. The method uses a wet extraction, cleanup by solid-phase extraction, and quantitation and separation by liquid chromatography (LC). In this paper, we compare the performance of this method with that of a previously reported LC assay for the determination of emamectin benzoate in fish feed. Although similar to the previous method, the new procedure uses a different sample pretreatment, wet extraction, and quantitation method. The performance of the new method was compared with that of the previously reported method by analyses of 22 medicated feed samples from various commercial sources. A comparison of the results presented here reveals slightly lower assay values obtained with the new method. Although a paired sample t-test indicates the difference in results is significant, this difference is within the method precision of either procedure.

New Method To Estimate Total Polyphenol Excretion: Comparison of Fast Blue BB versus Folin-Ciocalteu Performance in Urine.

PubMed

Hinojosa-Nogueira, Daniel; Muros, Joaquín; Rufián-Henares, José A; Pastoriza, Silvia

2017-05-24

Polyphenols are bioactive substances of vegetal origin with a significant impact on human health. The assessment of polyphenol intake and excretion is therefore important. The Folin-Ciocalteu (F-C) method is the reference assay to measure polyphenols in foods as well as their excretion in urine. However, many substances can influence the method, making it necessary to conduct a prior cleanup using solid-phase extraction (SPE) cartridges. In this paper, we demonstrate the use of the Fast Blue BB reagent (FBBB) as a new tool to measure the excretion of polyphenols in urine. Contrary to F-C, FBBB showed no interference in urine, negating the time-consuming and costly SPE cleanup. In addition, it showed excellent linearity (r 2 = 0.9997), with a recovery of 96.4% and a precision of 1.86-2.11%. The FBBB method was validated to measure the excretion of polyphenols in spot urine samples from Spanish children, showing a good correlation between polyphenol intake and excretion.

Clean-up of aqueous acetone vegetable extracts by solid-matrix partition for pyrethroid residue determination by gas chromatography-electron-capture detection.

PubMed

Di Muccio, A; Barbini, D A; Generali, T; Pelosi, P; Ausili, A; Vergori, F; Camoni, I

1997-03-21

Disposable, ready-to-use cartridges filled with macroporous diatomaceous material are used to carry out a partition clean-up that, in a single step, is capable of transferring pesticide residues from aqueous acetone extracts into light petroleum-dichloromethane (75:25, v/v). This procedure takes the place of some functions (such as separatory-funnel partition, drying over anhydrous sodium sulphate and partial adsorption clean-up) usually performed by separate steps in classical schemes. Fourteen pyrethroid pesticides, including tefluthrin, tetramethrin, cyphenothrin, cyfluthrin, flucythrinate, tau-fluvalinate, deltamethrin, bioallethrin, fenpropathrin, lambda-cyhalothrin, permethrin, alpha-cypermethrin, esfenvalerate and tralomethrin were determined using the described procedure with satisfactory recoveries for most of them, at spiking levels ranging from 0.08 to 0.82 mg/kg for the different compounds. Crops subjected to the described procedure included strawberry, apple, and orange gave extracts containing a mass of co-extractives that was between 5 and 30 mg. Compared with classical schemes, the described procedure is simple, less labour intensive, allows parallel handling of several extracts and does not require the preparation and maintenance of equipment. Troublesome emulsions such as those frequently observed in separation funnel partitioning do not occur.

Development and validation of a high-performance liquid chromatography method for determination of lisinopril in human plasma by magnetic solid-phase extraction and pre-column derivatization.

PubMed

Rastkari, Noushin; Ahmadkhaniha, Reza

2018-03-01

A sensitive, reliable and simple HPLC method was developed for the determination of lisinopril in human plasma. The method consists of extraction and clean-up steps based on magnetic solid-phase extraction and pre-column derivatization with a fluorescent reagent. The mobile phase consisted of a mixture of methanol-sodium dihydrogen phosphate (pH 3.0; 0.005 m; 75:25, v/v). The flow rate was set at 0.7 mL/min. Fluorescence detection was performed at 470nm excitation and 530nm emission wavelengths. Total chromatography run time was 5 min. The average extraction recovery of lisinopril and fluvoxamine (internal standard) was ≥82.8%. The limits of detection and quantification were determined as 1 and 3 ng/mL respectively. The method exhibited a linear calibration line over the concentration range of 3-1000 ng/mL with coefficient of determination (r 2 ) of ≥0.98. The within-run and between-run precisions were satisfactory with values of CV of 1.8-12.8% (accuracy from 99.2 to 94.7%) and 2.4-13.7% (accuracy from 99.5 to 92.2%), respectively. These developments led to considerable improvement in method sensitivity and reliability. The method was validated according to the US Food and Drug Administration guidelines. Therefore, it can be considered as a suitable method for determination of lisinopril in plasma samples. Copyright © 2017 John Wiley & Sons, Ltd.

Determination of isothiazolinone preservatives in cosmetics and household products by matrix solid-phase dispersion followed by high-performance liquid chromatography-tandem mass spectrometry.

PubMed

Alvarez-Rivera, Gerardo; Dagnac, Thierry; Lores, Marta; Garcia-Jares, Carmen; Sanchez-Prado, Lucia; Lamas, J Pablo; Llompart, Maria

2012-12-28

In this work, the development of a new efficient methodology applying, for the first time, matrix solid phase dispersion (MSPD) for the determination of sensitizer isothiazolinone biocides in cosmetics and household products - 2-methyl-3-isothiazolinone (MI), 5-chloro-2-methyl-3-isothiazolinone (CMI), 1,2-benzisothiazolinone (BzI) and 2-octyl-3-isothiazolinone (OI) - is described. The main factors affecting the MSPD extraction procedure, the dispersive phase and the elution solvent, are assessed and optimized through a multicategorical experimental design, using a real cosmetic sample. The most suitable extraction conditions comprise the use of 2g of florisil as dispersive phase and 5 mL of methanol as elution solvent. Subsequently, the extract is readily analyzed by HPLC-MS/MS without any further clean-up or concentration steps. Method performance was evaluated demonstrating to have a broad linear range (R(2)>0.9980) and limits of detection (LOD) and quantification (LOQ) at the low nanogram per gram level, which are well below the required limits for UE regulation compliance. Satisfactory recoveries above 80%, except for MI (mean values close to 60%), were obtained. In all cases, the method precision (% RSD) was lower than 7%, making this low cost extraction method reliable for routine control. The validated methodology was finally applied to the analysis of a wide variety of cosmetics and household products. Most of the real samples analyzed have been shown to comply with the current European Cosmetic Regulation, although the results obtained for some rinse-off cosmetics (e.g. baby care products) revealed high isothiazolinone content. Copyright © 2012 Elsevier B.V. All rights reserved.

Validation of a Chiral Liquid Chromatographic Method for the Degradation Behavior of Flumequine Enantiomers in Mariculture Pond Water.

PubMed

Wang, Yan-Fei; Gao, Xiao-Feng; Jin, Huo-Xi; Wang, Yang-Guang; Wu, Wei-Jian; Ouyang, Xiao-Kun

2016-09-01

In this work, flumequine (FLU) enantiomers were separated using a Chiralpak OD-H column, with n-hexane-ethanol (20:80, v/v) as the mobile phase at a flow rate of 0.6 mL/min. Solid phase extraction (SPE) was used for cleanup and enrichment. The limit of detection, limit of quantitation, linearity, precision, and intra/interday variation of the chiral high-performance liquid chromatography (HPLC) method were determined. The developed method was then applied to investigate the degradation behavior of FLU enantiomers in mariculture pond water samples. The results showed that the degradation of FLU enantiomers under natural, sterile, or dark conditions was not enantioselective. Chirality 28:649-655, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Influence of pre-treatment process on matrix effect for the determination of musk fragrances in fish and mussel.

PubMed

Vallecillos, Laura; Pocurull, Eva; Borrull, Francesc

2015-03-01

Musk compounds are widely used as fragrances in personal care products. On account of their widespread use and their low biodegradation, they can be found in environmental samples. In our study two extraction methodologies were compared and different clean-up strategies were also studied in order to develop a reliable analytical method, with minimum matrix effect and good detection limits, to determine synthetic musk fragrances- six polycyclic musks, three nitro musks and the degradation product of one polycyclic musk- in fish and mussel samples. The first extraction technique involves a QuEChERS extraction, a consolidate extraction methodology in the field of food analysis of growing interest over recent years, followed by a dispersive solid-phase extraction (dSPE) as clean-up strategy. The second extraction technique consists of a conventional pressurised liquid extraction (PLE) with dichloromethane and an in-cell clean-up to decrease the matrix effect and remove the undesired components(⁎)present in PLE extracts. Large volume injection (LVI) followed by gas chromatography-ion trap-tandem mass spectrometry (GC-IT-MS/MS) was chosen as the separation and detection technique. Validation parameters, such as method detection limits and method quantification limits were found at ng g(-1) levels for both fish and mussel matrices. Good levels of intra-day and inter-day repeatabilities were obtained analysing fish and mussel samples spiked at 50 ng g(-1) (d.w.) (n=5, RSDs<17%). The developed PLE/GC-IT-MS/MS method was successfully applied to determine the target musk fragrances present in fish and mussel samples from the local market in Tarragona and fish samples from the Ebro River. The results showed the presence of galaxolide (2.97-18.04 ng g(-1) (d.w.)) and tonalide (1.17-8.42 ng g(-1) (d.w.)) in all the samples analysed, while the remaining polycyclic musks such as cashmeran, celestolide and phantolide, were only detected in some of the fish samples analysed. None of the samples analysed contained detectable traces of the nitro musks studied. Copyright © 2014 Elsevier B.V. All rights reserved.

Use of itaconic acid-based polymers for solid-phase extraction of deoxynivalenol and application to pasta analysis.

PubMed

Pascale, Michelangelo; De Girolamo, Annalisa; Visconti, Angelo; Magan, Naresh; Chianella, Iva; Piletska, Elena V; Piletsky, Sergey A

2008-02-25

Molecular modelling and computational design were used to identify itaconic acid (IA) as a functional monomer with high affinity towards deoxynivalenol (DON), a Fusarium-toxin frequently occurring in cereals. IA-based polymers were photochemically synthesised in dimethyl formamide (porogen) using ethylenglycol dimethacrylate as cross-linker and 1,1'-azo-bis(cyclohexane carbonitrile) as initiator, and the relevant binding interactions with DON in solvents with different polarity were investigated. The performances of the non-imprinted IA-based polymer (blank polymer, BP) and the corresponding molecularly imprinted polymer (MIP) were compared using DON as a template. Both BP and MIP were able to bind about 90% DON either in toluene, water or water containing 5% polyethylene glycol. Non-imprinted polymers with different molar ratios of IA to cross-linker were evaluated as adsorbents for solid-phase extraction (SPE) clean-up and pre-concentration of DON from wheat and pasta samples prior to HPLC analysis. Samples were extracted with PBS/0.1M EDTA solution and cleaned up through a cartridge containing blank IA-based polymer. The column was washed with PBS (pH 9.2) and the toxin was eluted with methanol and quantified by reversed-phase HPLC with UV detector (lambda=220nm), using methanol:water:acetic acid (15:85:0.1, v/v/v) as the mobile phase. Effective removal of matrix interferences was observed only for pasta with DON recoveries higher than 70% (RSD<7%, n=3) at levels close to or higher than EU regulatory limit.

Determination of selected UV filters in indoor dust by matrix solid-phase dispersion and gas chromatography-tandem mass spectrometry.

PubMed

Negreira, N; Rodríguez, I; Rubí, E; Cela, R

2009-07-31

A simple, inexpensive sample preparation procedure, based on the matrix solid-phase dispersion (MSPD) technique, for the determination of six UV filters: 2-ethylhexyl salicylate (EHS), 3,3,5-trimethylcyclohexyl salicylate (Homosalate, HMS), 3-(4-methylbenzylidene) camphor (4-MBC), isoamyl-p-methoxycinnamate (IAMC), 2-ethylhexyl-p-methoxycinnamate (EHMC) and octocrylene (OCR), in dust from indoor environments is presented and the influence of several operational parameters on the extraction performance discussed. Under the final working conditions, sieved samples (0.5 g) were mixed with the same amount of anhydrous sodium sulphate and dispersed with 2 g of octadecyl bonded silica (C18) in a mortar with a pestle. This blend was transferred to a polypropylene solid-phase extraction cartridge containing 2 g of activated silica, as the clean-up co-sorbent. The cartridge was first rinsed with 5 mL of n-hexane and the analytes were then recovered with 4 mL of acetonitrile. This extract was adjusted to 1 mL, filtered and the compounds were determined by gas chromatography combined with tandem mass spectrometry (GC-MS/MS). Recoveries for samples spiked at two different concentrations ranged between 77% and 99%, and the limits of quantification (LOQs) of the method between 10 and 40 ng g(-1). Analysis of settled dust from different indoor areas, including private flats, public buildings and vehicle cabins, showed that EHMC and OCR were ubiquitous in this matrix, with maximum concentrations of 15 and 41 microg g(-1), respectively. Both UV filters were also quantified in dust reference material SRM 2585 for first time. EHS, 4-MBC and IAMC were detected in some of the analyzed samples, although at lower concentrations than EHMC and OCR.

N-doped carbon nanotubes-reinforced hollow fiber solid-phase microextraction coupled with high performance liquid chromatography for the determination of phytohormones in tomatoes.

PubMed

Han, Xiao-Fei; Chen, Juan; Shi, Yan-Ping

2018-08-01

A N-doped carbon nanotubes-reinforced hollow fiber solid-phase microextraction (N-doped CNTs-HF-SPME) method was developed for determination of two naphthalene-derived phytohormones, 1-naphthalene acetic acid (NAA) and 2-naphthoxyacetic acid (2-NOA), at trace levels in tomatoes. N-doped CNTs were dispersed in ultrapure water with the assistance of surfactant, and then immobilized into the pores of hollow fiber by capillary forces and sonification. The resultant N-doped CNTs-HF was wetted with 1-octanol, subsequently immersed into the tomato samples to extract the target analytes under a magnetic stirring, and then desorbed with methanol by sonication prior to chromatographic analysis. Compared with CNTs, the surface hydrophilicity of N-doped CNTs was improved owing to the doping of nitrogen atoms, and a uniform dispersion was formed, thus greatly simplifying the preparation process and reducing waste of materials. In addition, N-doped CNTs-HF exhibits a more effective extraction performance for NAA and 2-NOA on account of the introduction of Lewis-basic nitrogen. It is worth to mention that owing to the clean-up function of HF, there are not any complicated sample pretreatment procedures prior to the microextraction. To achieve the highest extraction efficiency, important microextraction parameters including the length and the concentration level of N-doped CNTs in surfactant solution, extraction time, desorption conditions such as the type and volume of solvents, pH value, stirring rate and volume of the donor phase were thoroughly investigated and optimized. Under the optimal conditions, the method showed 165- and 123-fold enrichment factors of NAA and 2-NOA, good inter-fiber repeatability and batch-to-batch reproducibility, good linearity with correlation coefficients higher than 0.9990, low limits of detection and quantification (at ng g -1 levels), and satisfactory recoveries in the range of 83.10-108.32% at three spiked levels. The proposed method taking advantages of both excellent adsorption performance of N-doped CNTs and the clean-up function of HF, was a simple, green, efficient and cost-effective enrichment procedure for the determination of trace NAA and 2-NOA in tomatoes. Copyright © 2018 Elsevier B.V. All rights reserved.

Determination of phenolic xenoestrogens in water by liquid chromatography with coulometric-array detection.

PubMed

Inoue, Koichi; Yoshie, Yuriko; Kondo, Sachiko; Yoshimura, Yoshihiro; Nakazawa, Hiroyuki

2002-02-08

A sensitive method for the simultaneous determination of phenolic xenoestrogens such as bisphenol A, 2,4-dichlorophenol, 4-tert,-butylphenol, 4-n2-pentylphenol, 4-n-hexylphenol, 4-n-heptylphenol, 4-octylphenol, 4-nonylphenol was developed using reversed-phase LC and coulometric-array detection. Stepwise gradient elution with phosphoric acid in water-acetonitrile was used. The calibration curves were linear in the range of 5.0 (or 10.0)-1000 ng ml(-1) with correlation coefficients of 0.9978-0.9999, the limits of detection were 0.01-0.02 ng ml(-1). Sample clean-up was performed by solid-phase extraction (SPE) using 3M Empore extraction disks. Three commercial sorbents, C18, SDB-XD (styrene-divinylbenzene polymer) and SDB-RPS (sulfonated styrene-divinylbenzene polymer) were compared. The highest recoveries were obtained with SDB-RPS. They were above 70% with a relative standard deviation of less than 15%. The proposed method was applied to the determination of phenolic xenoestrogens in various water samples.

Determination of tilmicosin residues in chicken, cattle, swine, and sheep tissues by liquid chromatography.

PubMed

Stobba-Wiley, C M; Chang, J P; Elsbury, D T; Moran, J W; Turner, J M; Readnour, R S; Stobba-Wiley, C M; Chang, J P; Elsbury, D T; Moran, J W; Turner, J M; Readnour, R S

2000-01-01

A method was developed and validated for determination and quantitation of tilmicosin residues in swine, cattle, and sheep edible tissues, as well as chicken fat, skin, and muscle over a concentration range of 0.025 microg/g-20 microg/g. For chicken kidney and liver, the method was validated over a range of 0.060 microg/g-20 microg/g. The tissue sample was extracted with methanol and a C18 cartridge was used for solid-phase extraction cleanup. A reversed-phase gradient liquid chromatographic method with detection at 280 nm was used to separate the tilmicosin from matrix components in 30 min run time. The limit of quantitation (LOQ) of the method was 0.025 microg/g for all tested tissues except chicken kidney and liver, for which the LOQ was 0.06 microg/g. Average recoveries for tissue samples ranged from 73 to 98%. Relative standard deviation values ranged from 0.6 to 14.7%.

Preparation and evaluation of a mixed-bed immunoaffinity column for selective purification of sixteen sulfonamides in pork muscle.

PubMed

Li, Yingguo; Chen, Yiqiang; Li, Zhengguo; Zhang, Lei; Li, Xianliang; Xi, Cunxian; Wang, Guomin; Wang, Xiong; Guo, Qi; Li, Na

2012-03-01

This paper describes the preparation of a novel mixed-bed immunoaffinity chromatography (IAC) column by coupling four monoclonal antibodies against different sulfonamides (SAs) to Sepharose 4B. The IAC column can be used to simultaneously extract and purify 16 SAs in pork muscle. The dynamic column capacities for all SAs in mixed standard solution were between 312 and 479 ng/mL gel. After simple extraction and IAC cleanup, the sample solution can be directly injected for liquid chromatography-ultraviolet analysis. The recoveries of SAs from spiked samples at levels of 25, 50 and 100 µg/kg ranged from 83.3 to 103.1% with variation coefficient less than 8.6%. The comparison of IAC with liquid-liquid extraction and solid phase extraction indicated that IAC has better purification effect and needs less organic solution than conventional methods, thus it would be an ideal method for selective purification of SAs in pork muscle.

Review of in situ derivatization techniques for enhanced bioanalysis using liquid chromatography with mass spectrometry.

PubMed

Baghdady, Yehia Z; Schug, Kevin A

2016-01-01

Accurate and specific analysis of target molecules in complex biological matrices remains a significant challenge, especially when ultra-trace detection limits are required. Liquid chromatography with mass spectrometry is often the method of choice for bioanalysis. Conventional sample preparation and clean-up methods prior to the analysis of biological fluids such as liquid-liquid extraction, solid-phase extraction, or protein precipitation are time-consuming, tedious, and can negatively affect target recovery and detection sensitivity. An alternative or complementary strategy is the use of an off-line or on-line in situ derivatization technique. In situ derivatization can be incorporated to directly derivatize target analytes in their native biological matrices, without any prior sample clean-up methods, to substitute or even enhance the extraction and preconcentration efficiency of these traditional sample preparation methods. Designed appropriately, it can reduce the number of sample preparation steps necessary prior to analysis. Moreover, in situ derivatization can be used to enhance the performance of the developed liquid chromatography with mass spectrometry-based bioanalysis methods regarding stability, chromatographic separation, selectivity, and ionization efficiency. This review presents an overview of the commonly used in situ derivatization techniques coupled to liquid chromatography with mass spectrometry-based bioanalysis to guide and to stimulate future research. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hydrophilic interaction chromatography based solid-phase extraction and MALDI TOF mass spectrometry for revealing the influence of Pseudomonas fluorescens on phospholipids in salmon fillet.

PubMed

Shen, Qing; Yang, Qi; Cheung, Hon-Yeung

2015-02-01

Salmon is a popular food but it is easily susceptible to spoilage by contamination with microorganisms. In this study, a method using hydrophilic interaction chromatography (HILIC)-based solid-phase extraction (SPE) and matrix-assisted laser desorption and ionization time-of-flight/time-of-flight mass spectrometry was developed and applied to reveal the effect of Pseudomonas fluorescens on salmon fillet during the shelf-life period by measuring the changes in the levels of phosphatidylcholine and phosphatidylethanolamine. Fresh samples were inoculated with P. fluorescens (10(6) cfu g(-1)) for 30 s, and lipids were extracted at 0, 24, 48, and 72 h. A homemade SPE cartridge packed with HILIC sorbent (silica derivatized with 1,2-dihydroxypropane) was used for matrix cleanup prior to analysis by mass spectrometry. In total, 30 phospholipids and 16 lysophospholipids were detected and elucidated. The results revealed that the content of phospholipids decreased significantly, whereas that of lysophospholipids increased initially, followed by a gradual reduction as the cold storage time increased. The contamination by P. fluorescens negatively affected the quality of fresh salmon without obvious physical changes, but it posed a potential threat to human health. This study suggests that the well-established method could be used for detecting phospholipids in salmon fillet and perhaps other foods as well.

Multiresidue analysis of endocrine-disrupting compounds and perfluorinated sulfates and carboxylic acids in sediments by ultra-high-performance liquid chromatography-tandem mass spectrometry.

PubMed

Cavaliere, Chiara; Capriotti, Anna Laura; Ferraris, Francesca; Foglia, Patrizia; Samperi, Roberto; Ventura, Salvatore; Laganà, Aldo

2016-03-18

A multiresidue analytical method for the determination of 11 perfluorinated compounds and 22 endocrine-disrupting compounds (ECDs) including 13 natural and synthetic estrogens (free and conjugated forms), 2 alkylphenols, 1 plasticiser, 2 UV-filters, 1 antimicrobial, and 2 organophosphorus compounds in sediments has been developed. Ultrasound-assisted extraction followed by solid phase extraction (SPE) with graphitized carbon black (GCB) cartridge as clean-up step were used. The extraction process yield was optimized in terms of solvent composition. Then, a 3(2) experimental design was used to optimize solvent volume and sonication time by response surface methodology, which simplifies the optimization procedure. The final extract was analyzed by ultra-high performance liquid chromatography coupled with tandem mass spectrometry. The optimized sample preparation method is simple and robust, and allows recovery of ECDs belonging to different classes in a complex matrix such as sediment. The use of GCB for SPE allowed to obtain with a single clean-up procedure excellent recoveries ranging between 75 and 110% (relative standard deviation <16%). The developed methodology has been successfully applied to the analysis of ECDs in sediments from different rivers and lakes of the Lazio Region (Italy). These analyses have shown the ubiquitous presence of chloro-substituted organophosphorus flame retardants and bisphenol A, while other analyzed compounds were occasionally found at concentration between the limit of detection and quantification. Copyright © 2016 Elsevier B.V. All rights reserved.

Development and validation of an HPLC method for the simultaneous determination of tocopherols, tocotrienols and carotenoids in cereals after solid-phase extraction.

PubMed

Irakli, Maria N; Samanidou, Victoria F; Papadoyannis, Ioannis N

2011-06-01

The increasing interest in antioxidant properties of cereal and cereal-based products has prompted the development of a simple and reliable HPLC method for the simultaneous determination of important phytochemicals like tocopherols (T), tocotrienols (T3) and carotenoids. Separation was carried out on a Nucleosil 100 C(18) column, 5 μm (250 mm × 4.6 mm) thermostated at 25 °C, using a linear gradient elution system starting with methanol and ending with a mixture of methanol-isopropanol-acetonitrile. All separated compounds including the internal standard (α-tocopherol acetate) were eluted within 16 min and detected by dual detection: fluorescence for tocopherols and tocotrienols at 290 nm excitation and 320 nm emission and UV-vis photodiode array detection for lutein and β-carotene at 450 nm. Detection limits ranged from 0.2 μg/g (β-carotene) to 1.60 μg/g (α-tocopherol). The intra- and inter-assay coefficients of variation were calculated by using cereals with different levels of lipophilic antioxidants. The extraction method involved sample saponification and clean-up by solid-phase extraction (SPE). The extraction recoveries obtained using OASIS HLB SPE cartridges and dichloromethane as eluent were in the range of 90.2-110.1%, with RSD lower than 10%. The method was successfully applied to cereals: durum wheat, bread wheat, rice, barley, oat, rye, corn and triticale. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multi-residue analysis of 26 organochlorine pesticides in Alpinia oxyphylla by GC-ECD after solid phase extraction and acid cleanup.

PubMed

Zhao, Xiangsheng; Zhou, Yakui; Kong, Weijun; Gong, Bao; Chen, Deli; Wei, Jianhe; Yang, Meihua

2016-04-01

A simple and effective multi-residue method was developed and validated for the analysis of 26 organochlorine pesticide residues in Alpinia oxyphylla by a gas chromatography with an electron capture detector (GC-ECD). The target pesticides were extracted by sonication and cleaned up with florisil solid phase extraction and sulphuric acid. Some crucial parameters, including extraction solvent and time, sorbent type, elute solvent and concentration of sulphuric acid were optimized to improve the performance of sample preparation procedure. The optimized method gave high sensitivity with detection limit ranging from 0.1 to 2.0μg/kg. Matrix-matched calibration was employed for the quantification, and a wide linear range (from 1.0 to 1000μg/kg) with r(2) values ranging from 0.9971 to 0.9998 was obtained. For the majority of the tested pesticides, the average recoveries were in acceptable range (between 70% and 110%) with relative standard deviation values below 15.0%. Matrix effect was evaluated for target compounds through the study of ratio of peak area obtained in the solvent and blank matrix. The proposed method was applied to simultaneously analyze 26 pesticides in 55 batches of Alpinia oxyphylla samples. 3 samples were found to be positive with four pesticides (α-BHC, quintozene, trans-chlordane and op'-DDD), which were confirmed by gas chromatography-mass spectrometry (GC-MS) in selective ion monitoring (SIM) mode. Copyright © 2016 Elsevier B.V. All rights reserved.

Methods of analysis by the U.S. Geological Survey Organic Geochemistry Research Group; determination of glyphosate, aminomethylphosphonic acid, and glufonsinate in water using online solid-phase extraction and high-performance liquid chromat

USGS Publications Warehouse

Lee, E.A.; Strahan, A.P.; Thurman, E.M.

2001-01-01

An analytical method for the determination of glyphosate, its principal degradation compound, aminomethylphosphonic acid (AMPA), and glufosinate in water with varying matrices has been developed. Four different sample matrices fortified at 0.2 and 2.0 ?g/L (micrograms per liter) were analyzed using precolumn derivatization with 9-fluorenylmethylchloroformate (FMOC). After derivatization, cleanup and concentration were accomplished using automated online solid-phase extraction followed by elution with the mobile phase allowing for direct injection into a liquid chromatograph/mass spectrometer (LC/MS). Analytical conditions for MS detection were optimized, and quantitation was carried out using the following representative ions: 390 and 168 for glyphosate; 332, 110, and 136 for AMPA; and 402, 180, and 206 for glufosinate. Matrix effects were minimized by utilizing standard addition for quantification and an isotope-labeled glyphosate (2-13C,15N) as the internal standard. Method detection limits (MDLs) were 0.084 ?g/L for glyphosate, 0.078 ?g/L for AMPA, and 0.057 ?g/L for glufosinate. The method reporting limits (MRLs) were set at 0.1 ?g/L for all three compounds. The mean recovery values ranged from 88.0 to 128.7 percent, and relative standard deviation values ranged from 5.6 to 32.6 percent.

Determination of sulfonamides in animal tissues by modified QuEChERS and liquid chromatography tandem mass spectrometry.

PubMed

Wen, Ching-Hsuan; Lin, Shu-Ling; Fuh, Ming-Ren

2017-03-01

In this study, the salting-out solvent extraction and dispersive solid-phase extraction (dSPE) clean-up steps in QuEChERS (quick, easy, cheap, effective, rugged, and safe) method were optimized to reduce matrix effect and efficiently extract target sulfonamides from a variety of edible animal tissues. The extracted sulfonamides were then analyzed using liquid chromatography tandem mass spectrometry (LC-MS/MS). Good extraction recoveries (74.0-100.3% in five different sources of animal tissues; n=3) with acceptable matrix effect (<10%, except for liver samples) were obtained using the proposed method. For the first time, a commercial ND-lipids cartridge was used to remove hydrophobic matrix components from fat-rich animal tissues in the clean-up step of QuEChERS. In addition, good linearity (0.125-12.5ngg -1 ) was observed using matrix-matched calibration (in beef). Limits of detection (LODs) were estimated at 0.01-0.03ngg -1 in beef, pork, and chicken samples. For beef tripe and pig liver samples, the LODs were in the range of 0.02-0.04ngg -1 . Good intra-day/inter-day precision (1.0-10.5%/0.4-8.0%) and accuracy (95.2-107.2%/97.8-102.1%) were also achieved using the modified QuEChERS for sample pretreatment. The applicability of the modified QuEChERS-LC-MS/MS method was demonstrated by determining the occurrence of target sulfonamides in various edible animal tissues for potential food safety analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

Optimization of a liquid chromatographic method for determination of malachite green and its metabolites in fish tissues

USGS Publications Warehouse

Plakas, S.M.; ELSaid, K.R.; Stehly, G.R.; Roybal, J.E.

1995-01-01

A liquid chromatographic (LC) method was adapted and optimized for the determination of malachite green and its metabolites in fish plasma and muscle, Residues in plasma were extracted with acetonitrile, the extract was evaporated to dryness, and residues were resolubilized for LC analysis, Residues in muscle were extracted with an acetonitrile-acetate buffer mixture, reextracted with acetonitrile, and partitioned into methylene chloride with final cleanup on alumina and propylsulfonic acid solid-phase extraction columns, Residue levels were determined by using an LC cyano column with a PbO2 postcolumn and visible detection (618 nm). Overall mean recoveries of parent malachite green (MG-C) and its major metabolite, leucomalachite green (MG-L), from plasma were 93 and 87%, respectively, at fortification levels ranging from 25 to 250 ppb, Overall mean recoveries of MG-C and MG-L from muscle were 85 and 95%, respectively, at fortification levels ranging from 5 to 100 ppb, Relative standard deviations (RSDs) of recoveries at all fortification levels ranged from 3.9 to 7.0% for plasma and from 2.1 to 5.2% for muscle, The method was applied to incurred residues in tissues sampled from catfish after waterborne exposure to [C-14]MG-C. Mean recoveries of total radioactive residues in plasma and muscle throughout the extraction and cleanup process were 88 and 87%, respectively, and corresponding RSDs for MG-C and MG-L were in the same range as those for fortified tissues, MG-L, was confirmed as the major metabolite of MG-C in catfish.

Determination of organophosphorus flame retardants in fish by pressurized liquid extraction using aqueous solutions and solid-phase microextraction coupled with gas chromatography-flame photometric detector.

PubMed

Gao, Zhanqi; Deng, Yuehua; Yuan, Wenting; He, Huan; Yang, Shaogui; Sun, Cheng

2014-10-31

A novel method was developed for the determination of organophosphorus flame retardants (PFRs) in fish. The method consists of a combination of pressurized liquid extraction (PLE) using aqueous solutions and solid-phase microextraction (SPME), followed by gas chromatography-flame photometric detector (GC-FPD). The experimental parameters that influenced extraction efficiency were systematically evaluated. The optimal responses were observed by extracting 1g of fish meat with the solution of water:acetonitrile (90:10, v/v) at 150°C for 5min and acid-washed silica gel used as lipid sorbent. The obtained extract was then analyzed by SPME coupled with GC-FPD without any additional clean-up steps. Under the optimal conditions, the proposed procedure showed a wide linear range (0.90-5000ngg(-1)) obtained by analyzing the spiked fish samples with increasing concentrations of PFRs and correlation coefficient (R) ranged from 0.9900 to 0.9992. The detection limits (S/N=3) were in the range of 0.010-0.208ngg(-1) with standard deviations (RSDs) ranging from 2.0% to 9.0%. The intra-day and inter-day variations were less than 9.0% and 7.8%, respectively. The proposed method was successfully applied to the determination of PFRs in real fish samples with recoveries varying from 79.8% to 107.3%. The results demonstrate that the proposed method is highly effective for analyzing PFRs in fish samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Simple and sensitive method for quantification of fluorescent enzymatic mature and senescent crosslinks of collagen in bone hydrolysate using single-column high performance liquid chromatography.

PubMed

Viguet-Carrin, S; Gineyts, E; Bertholon, C; Delmas, P D

2009-01-01

A rapid high performance liquid chromatographic method was developed including an internal standard for the measurement of mature and senescent crosslinks concentration in non-demineralized bone hydrolysates. To avoid the demineralization which is a tedious step, we developed a method based on the use of a solid-phase extraction procedure to clean-up the samples. It resulted in sensitive and accurate measurements: the detection limits as low as 0.2 pmol for the pyridimium crosslinks and 0.02 pmol for the pentosidine. The inter- and intra-assay coefficients of variation were as low as 5% and 2%, respectively, for all crosslinks.

Inexpensive, effective novel activated carbon fibers for sample cleanup: application to multipesticide residue analysis in food commodities using a QuEChERS method.

PubMed

Singh, Shiv; Srivastava, Anshuman; Singh, Sheelendra Pratap

2018-03-01

Phenolic resin based activated carbon fibers (ACFs) were applied for the first time as a reversed-dispersive solid-phase extraction (r-DSPE) sorbent. A modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was applied to determine 26 pesticides (organophosphates, organochlorines, synthetic pyrethroids, and herbicides) in different complex matrices, including cauliflower, cucumber, banana, apple, wheat, and black gram. Different physicochemical characterization techniques were used to investigate the engineering and structural properties of the r-DSPE sorbent. All the chromatographic analyses were performed with a gas chromatograph equipped with an electron capture detector. The recoveries of all 26 pesticides were acceptable (70-120%), with relative standard deviations of less than 15%. The limit of detection and the limit of quantification were 1.13-5.48 ng/g and 3.42-16.60 ng/g, respectively. In the original QuEChERS method, primary secondary amine is extensively used as the r-DSPE sorbent in the cleanup process, but it is eightfold more expensive than the ACFs used in this study. Therefore, the modified QuEChERS method using ACFs during the cleanup process is more efficient, cheaper, and more robust to determine pesticides from different types of matrices, including vegetables, grains, and fruits, and ACFs could be used as a cost-effective alternative to primary secondary amine. Graphical Abstract Sample clean-up using PSA and ACF as r-DSPE sorbent in QuEChERS method.

Application of zirconium dioxide nanoparticle sorbent for the clean-up step in post-harvest pesticide residue analysis.

PubMed

Uclés, Ana; Herrera López, Sonia; Dolores Hernando, Maria; Rosal, Roberto; Ferrer, Carmen; Fernández-Alba, Amadeo R

2015-11-01

The use of yttria-stabilized zirconium dioxide nanoparticles as d-SPE clean-up sorbent for a rapid and sensitive liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method for the determination of post-harvest fungicides (carbaryl, carbendazim, chlorpropham, diphenylamine, ethoxyquin, flutriafol, imazalil, iprodione, methomyl, myclobutanil, pirimiphos-methyl, prochloraz, pyrimethanil, thiabendazole, thiophanate-methyl and tolclofos-methyl) in orange and pear samples has been evaluated and validated. The sample preparation was a modification of the QuEChERS extraction method using yttria-stabilized zirconium dioxide and multi-walled carbon nanotubes (MWCNTs) nanoparticles as the solid phase extraction (d-SPE) clean-up sorbents prior to injecting the ten-fold diluted extracts into the LC system. By using the yttria-stabilized zirconium dioxide extraction method, more recoveries in the 70-120% range were obtained - thus this method was used for the validation. Quantification was carried out using a matrix-matched calibration curve which was linear in the 1-500 µg kg(-1) range for almost all the pesticides studied. The validated limit of quantification was 10 µg kg(-1) for most of the studied compounds, except chlorpropham, ethoxyquin and thiophanate-methyl. Pesticide recoveries at the 10 and 100 µg kg(-1) concentration levels were satisfactory, with values between 77% and 120% and relative standard deviations (RSD) lower than 10% (n=5). The developed method was applied for the determination of selected fungicides in 20 real orange and pear samples. Four different pesticide residues were detected in 10 of these commodities; 20% of the samples contained pesticide residues at a quantifiable level (equal to or above the LOQs) for at least one pesticide residue. The most frequently-detected pesticide residues were: carbendazim, thiabendazole and imazalil-all were below the MRL. The highest concentration found was imazalil at 1175 µg kg(-1) in a pear sample. Copyright © 2015 Elsevier B.V. All rights reserved.

Multiresidue determination of pesticides in malt beverages by capillary gas chromatography with mass spectrometry and selected ion monitoring.

PubMed

Wong, Jon W; Webster, Michael G; Bezabeh, Dawit Z; Hengel, Mathew J; Ngim, Kenley K; Krynitsky, Alexander J; Ebeler, Susan E

2004-10-20

A method was developed to determine pesticides in malt beverages using solid phase extraction on a polymeric cartridge and sample cleanup with a MgSO4-topped aminopropyl cartridge, followed by capillary gas chromatography with electron impact mass spectrometry in the selected ion monitoring mode [GC-MS(SIM)]. Three GC injections were required to analyze and identify organophosphate, organohalogen, and organonitrogen pesticides. The pesticides were identified by the retention times of peaks of the target ion and qualifier-to-target ion ratios. GC detection limits for most of the pesticides were 5-10 ng/mL, and linearity was determined from 50 to 5000 ng/mL. Fortification studies were performed at 10 ng/mL for three malt beverages that differ in properties such as alcohol content, solids, and appearance. The recoveries from the three malt beverages were greater than 70% for 85 of the 142 pesticides (including isomers) studied. The data showed that the different malt beverage matrixes had no significant effect on the recoveries. This method was then applied to the screening and analysis of malt beverages for pesticides, resulting in the detection of the insectide carbaryl and the fungicide dimethomorph in real samples. The study indicates that pesticide levels in malt beverages are significantly lower than the tolerance levels set by the United States Environmental Protection Agency for malt beverage starting ingredients. The use of the extraction/cleanup procedure and analysis by GC-MS(SIM) proved effective in screening malt beverages for a wide variety of pesticides. Copyright 2004 American Chemical Society

Solution for blank and matrix difficulties encountered during phthalate analysis of edible oils by high performance liquid chromatography coupled with tandem mass spectrometry.

PubMed

Vavrouš, Adam; Pavloušková, Jana; Ševčík, Václav; Vrbík, Karel; Čabala, Radomír

2016-07-22

Worldwide production of phthalates has led to their undesirable presence in the food chain. Particularly edible oils have become an area of growing concern owing to numerous reported occurrences of phthalates. The analytical methods used in this field face difficulties associated mainly with matrix complexity or phthalate contamination which this study has aimed to describe and resolve. The proposed procedure consisting of liquid-liquid extraction, solid phase extraction and high performance liquid chromatography coupled with tandem mass spectrometry allowed us to analyze simultaneously 6 individual phthalates and 2 phthalate isomeric mixtures. DSC-18 SPE phase was selected for cleanup owing to the most efficient co-extract removal (assessed using high resolution mass spectrometry). Several sources of phthalate contamination were identified, however, the mobile phase was the most serious. The key improvement was achieved by equipping a contamination trap, a 50-mm reverse phase HPLC column, generating a delay between target and mobile phase peaks of the same compounds. RSDs ranging between 2.4 and 16 % confirm good precision and LOQs between 5.5 and 110μgkg(-1) reflect satisfactory blank management. With up to 19 occurrences in 25 analyzed edible oil samples and levels up to 33mgkg(-1), bis(2-ethylhexyl), diisononyl and diisodecyl phthalates were the most important contaminants. Copyright © 2016 Elsevier B.V. All rights reserved.

Determination of paraben preservatives in seafood using matrix solid-phase dispersion and on-line acetylation gas chromatography-mass spectrometry.

PubMed

Djatmika, Rosalina; Hsieh, Chih-Chung; Chen, Jhih-Ming; Ding, Wang-Hsien

2016-11-15

An effective method for determining four commonly detected paraben preservatives (methyl, ethyl, propyl and butyl paraben) in marketed seafood is presented. This method employs matrix solid-phase dispersion (MSPD) before identification and quantification of the paraben preservatives via on-line acetylation gas chromatography-mass spectrometry (GC-MS). Parameters affecting the extraction efficiency of MSPD were optimized through a Box-Behnken design method. Under optimal condition, 0.5-g of freeze-dried seafood was mixed with 0.5-g of anhydrous sodium sulfate, and dispersed with 1.0-g of Florisil using vortex. After that, the blend was transferred to a glass column containing 1.5-g of silica gel+C18 (w/w, 9:1), which acted as clean-up co-sorbents. Then, target analytes were eluted with 12mL of acetonitrile. The extract was then derivatized on-line in the GC injection-port through reaction with acetic anhydride, and the identity and quantity of the target analytes were determined by the GC-MS system. The limits of quantitation (LOQs) were 0.2 to 1.0ng/g (dry weight). Preliminary results showed that the total concentrations of four selected parabens ranged from 16.7 to 44.7ng/g (dry weight). Copyright © 2016 Elsevier B.V. All rights reserved.

Development and validation of a solid-phase extraction method coupled with HPLC-UV detection for the determination of biogenic amines in Chinese rice wine.

PubMed

Zhang, Ying; Li, Yan; Zhu, Xiao-Juan; Li, Min; Chen, Hao-Yu; Lv, Xiao-Ling; Zhang, Jian

2017-07-01

A reliable and accurate method for the determination of seven biogenic amines (BAs) was developed and validated with Chinese rice wine samples. The BAs were derivatised with dansyl chloride, cleaned up using solid-phase extraction (SPE) and separated by high-performance liquid chromatography (HPLC) coupled with ultraviolet (UV) detection. The optimised derivatisation reaction, conducted at pH 9.6 and 60°C for 30 min, ensured baseline separation and peak symmetry for each BA. SPE clean-up using Oasis MCX cartridges yielded good recovery rates for all BAs and effectively reduced matrix effects. The developed method shows good linearity with determination coefficients of more than 0.9989 over a concentration range of 0.1-100 mg l -1 . The limits of detection (LODs) for the investigated BAs ranged from 2.07 to 5.56 µg l -1 . The intra- and inter-day relative standard deviations (RSDs) ranged from 0.86% to 3.81% and from 2.13% to 3.82%, respectively. Spiking experiments showed that the overall recovery rates ranged from 85% to 113%. Thus, the proposed method was demonstrated as being suitable for simultaneous detection, with accurate and precise quantification, of BAs in Chinese rice wine.

Application of dispersive solid-phase extraction and ultra-fast liquid chromatography-tandem quadrupole mass spectrometry in food additive residue analysis of red wine.

PubMed

Chen, Xiao-Hong; Zhao, Yong-Gang; Shen, Hao-Yu; Jin, Mi-Cong

2012-11-09

A novel and effective dispersive solid-phase extraction (dSPE) procedure with rapid magnetic separation using ethylenediamine-functionalized magnetic polymer as an adsorbent was developed. The new procedure had excellent clean-up ability for the selective removal of the matrix in red wine. An accurate, simple, and rapid analytical method using ultra-fast liquid chromatography-tandem quadrupole mass spectrometry (UFLC-MS/MS) for the simultaneous determination of nine food additives (i.e., acesulfame, saccharin, sodium cyclamate, aspartame, benzoic acid, sorbic acid, stevioside, dehydroacetic acid, and neotame) in red wine was also used and validated. Recoveries ranging from 78.5% to 99.2% with relative standard deviations ranging from 0.46% to 6.3% were obtained using the new method. All target compounds showed good linearities in the tested range with correlation coefficients (r) higher than 0.9993. The limits of quantification for the nine food additives were between 0.10 μg/L and 50.0 μg/L. The proposed dSPE-UFLC-MS/MS method was successfully applied in the food-safety risk monitoring of real red wine in Zhejiang Province, China. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

Simultaneous analysis of nine aromatic amines in mainstream cigarette smoke using online solid-phase extraction combined with liquid chromatography-tandem mass spectrometry.

PubMed

Zhang, Jie; Bai, Ruoshi; Zhou, Zhaojuan; Liu, Xingyu; Zhou, Jun

2017-04-01

A fully automated analytical method was developed and validated by this present study. The method was based on two-dimensional (2D) online solid-phase extraction liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) to determine nine aromatic amines (AAs) in mainstream smoke (MSS) simultaneously. As a part of validation process, AAs yields for 16 top-selling commercial cigarettes from China market were evaluated by the developed method under both Health Canada Intensive (HCI) and ISO machine smoking regimes. The gas phase of MSS was trapped by 25 mL 0.6 M hydrochloric acid solution, while the particulate phase was collected on a glass fiber filter. Then, the glass fiber pad was extracted with hydrochloric acid solution in an ultrasonic bath. The extract was analyzed with 2D online SPE-LC-MS/MS. In order to minimize the matrix effects of sample on each analyte, two cartridges with different extraction mechanisms were utilized to cleanup disturbances of different polarity, which were performed by the 2D SPE. A phenyl-hexyl analytical column was used to achieve a chromatographic separation. Under the optimized conditions, the isomers of p-toluidine, m-toluidine and o-toluidine, 3-aminobiphenyl and 4-aminobiphenyl, and 1-naphthylamine and 2-naphthylamine were baseline separated with good peak shapes for the first time. The limits of detection for nine AAs ranged from 0.03 to 0.24 ng cig -1 . The recovery of the measurement of nine AAs was from 84.82 to 118.47%. The intra-day and inter-day precisions of nine AAs were less than 10 and 16%, respectively. Compared with ISO machine smoking regime, the AAs yields in MSS were 1.17 to 3.41 times higher under HCI machine smoking regime. Graphical abstract New method using online SPE-LC/MS/MS for analysis of aromatic amines in mainstream cigarette smoke.

Simultaneous Determination of Fluoroquinolones and Sulfonamides Originating from Sewage Sludge Compost

PubMed Central

Herodes, K.

2017-01-01

A simultaneous method for quantitative determination of traces of fluoroquinolones (FQs) and sulfonamides (SAs) in edible plants fertilized with sewage sludge was developed. The compounds were extracted from the plants by rapid and simple liquid extraction followed by extracts clean-up using solid phase extraction. The eluent additive 1,1,1,3,3,3-hexafluoro-2-propanol was used for liquid chromatographic detection to achieve separation of structurally similar antimicrobials like ciprofloxacin and norfloxacin. Identification and quantification of the compounds were performed using high-performance liquid chromatography with electrospray ionization mass spectrometry in selected reaction monitoring mode. Method was validated and extraction recoveries of FQs and SAs ranged from 66% to 93%. The limit of quantifications was from 5 ng/g in the case of ofloxacin to 40 ng/g for norfloxacin. The method precision ranged from 1.43% to 2.61%. The developed novel method was used to evaluate the plats antimicrobial uptake (potato (Solanum tuberosum L.), carrot (Daucus carota L.), lettuce (Lactuca sativa L.), and wheat (Triticum vulgare L.)) from soil and migration of the analytes inside the plants. PMID:28695191

Development and validation of an extraction method for the analysis of perfluoroalkyl substances in human hair.

PubMed

Kim, Da-Hye; Oh, Jeong-Eun

2017-05-01

Human hair has many advantages as a non-invasive sample; however, analytical methods for detecting perfluoroalkyl substances (PFASs) in human hair are still in the development stage. Therefore, the aim of this study was to develop and validate a method for monitoring 11 PFASs in human hair. Solid-phase extraction (SPE), ion-pairing extraction (IPE), a combined method (SPE+IPE) and solvent extraction with ENVI-carb clean-up were compared to develop an optimal extraction method using two types of hair sample (powder and piece forms). Analysis of PFASs was performed using liquid chromatography and tandem mass spectrometry. Among the four different extraction procedures, the SPE method using powdered hair showed the best extraction efficiency and recoveries ranged from 85.8 to 102%. The method detection limits for the SPE method were 0.114-0.796 ng/g and good precision (below 10%) and accuracy (66.4-110%) were obtained. In light of these results, SPE is considered the optimal method for PFAS extraction from hair. It was also successfully used to detect PFASs in human hair samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

Capillary-Channeled Polymer (C-CP) Fibers as a Stationary Phase for Sample Clean-Up of Protein Solutions for Matrix-Assisted Laser/Desorption Ionization Mass Spectrometry

NASA Astrophysics Data System (ADS)

Manard, Benjamin T.; Marcus, R. Kenneth

2012-08-01

Capillary-channeled polymer (C-CP) fibers are employed in a micropipette tip format to affect a stationary phase for the solid phase extraction (SPE) of proteins from buffer solutions prior to MALDI-MS analysis. Proteins readily adsorb to the polypropylene (PP) C-CP fibers while buffer species are easily washed off the tips using DI-H2O. Elution of the solutes is achieved with an aliquot of 50:50 ACN:H2O, which is compatible with the subsequent spotting on the MALDI target with the matrix solution. Lysozyme and cytochrome c are used as test species, with a primary buffer composition of 100 mM Tris-HCl. In this case, direct MALDI-MS produces no discernible protein signals. SPE on the C-CP fibers yields high fidelity mass spectra for 1 μL sample volumes. Limits of detection for cytochrome c in 100 mM Tris-HCl are on the order of 40 nM. Extraction of cytochrome c from buffer concentrations of up to 1 M Tris-HCl, provides signal recoveries that are suppressed by only ~50 % versus neat protein solutions. Finally, extraction of 3.1 μM cytochrome c from a synthetic urine matrix exhibits excellent recovery.

Screening of grapes and wine for azoxystrobin, kresoxim-methyl and trifloxystrobin fungicides by HPLC with diode array detection.

PubMed

De Melo Abreu, Susana; Correia, Manuela; Herbert, Paulo; Santos, Lúcia; Alves, Arminda

2005-06-01

The Quinone outside Inhibitors (QoI) are one of the most important and recent fungicide groups used in viticulture and also allowed by Integrated Pest Management. Azoxystrobin, kresoxim-methyl and trifloxystrobin are the main active ingredients for treating downy and powdery mildews that can be present in grapes and wines. In this paper, a method is reported for the analysis of these three QoI-fungicides in grapes and wine. After liquid-liquid extraction and a clean-up on commercial silica cartridges, analysis was by isocratic HPLC with diode array detection (DAD) with a run time of 13 min. Confirmation was by solid-phase micro-extraction (SPME), followed by GC/MS determination. The main validation parameters for the three compounds in grapes and wine were a limit of detection up to 0.073 mg kg(-1), a precision not exceeding 10.0% and an average recovery of 93% +/- 38.

A generic method for the determination of acrylamide in thermally processed foods.

PubMed

Gökmen, Vural; Senyuva, Hamide Z

2006-07-07

A generic sample preparation method for the determination of acrylamide in foods was developed. The method entails extraction with methanol, purification with Carrez I and II solutions, evaporation and solvent change to water, and cleanup with Oasis HLB solid-phase extraction (SPE) cartridge. The final extract was analyzed by liquid chromatography-mass spectrometry (LC-MS) for quantitation. The chromatographic separation was performed on ODS-3 column using the isocratic mixture of 0.01 mM acetic acid in 0.2% aqueous solution of formic acid at a flow rate of 0.6 ml/min at 25 degrees C. The recoveries of acrylamide from potato chips, biscuits and coffee ranged between 92.8 and 101.5% with relative standard deviations of 4.1% or less. The limit of detection (LOD) and the limit of quantitation (LOQ) were 2 ng/g and 6 ng/g in the basis of signal to noise ratios of 3:1 and 9:1, respectively.

Detection of multiple steroidal compounds in synthetic urine using comprehensive gas chromatography-mass spectrometry (GC×GC-MS) combined with a molecularly imprinted polymer clean-up protocol.

PubMed

Zulfiqar, Adnan; Morgan, Geraint; Turner, Nicholas W

2014-10-07

A method capable of screening for multiple steroids in urine has been developed, using a series of twelve structurally similar, and commercially relevant compounds as target analytes. A molecularly imprinted solid phase extraction clean-up step was used to make the sample suitable for injection onto a GC×GC-MS setup. Significant improvements compared to a commercially available C-18 material were observed. Each individual steroid was able to be separated and identified, using both the retention profile and diagnostic fragmentation ion monitoring abilities of the comprehensive chromatographic-mass spectrometry method. Effective LODs of between 11.7 and 27.0 pg were calculated for individual steroids, effectively equivalent to concentration levels of between 0.234 and 0.540 ng mL(-1) in urine, while the application of multiple screen was demonstrated using a 10 ng mL(-1) mixed sample. The nature of this study also removes the need for sample derivitisation which speeds up the screening process.

Importance Of Solid Phase Characterization To MNA Assessment

EPA Science Inventory

Technical recommendations have recently been published by the U.S. Environmental Protection Agency to address site characterization needed to support selection of Monitored Natural Attenuation (MNA) for cleanup of inorganic contaminant plumes in groundwater. Immobilization onto ...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This volume contains the interim change notice for sample preparation methods. Covered are: acid digestion for metals analysis, fusion of Hanford tank waste solids, water leach of sludges/soils/other solids, extraction procedure toxicity (simulate leach in landfill), sample preparation for gamma spectroscopy, acid digestion for radiochemical analysis, leach preparation of solids for free cyanide analysis, aqueous leach of solids for anion analysis, microwave digestion of glasses and slurries for ICP/MS, toxicity characteristic leaching extraction for inorganics, leach/dissolution of activated metal for radiochemical analysis, extraction of single-shell tank (SST) samples for semi-VOC analysis, preparation and cleanup of hydrocarbon- containing samples for VOCmore » and semi-VOC analysis, receiving of waste tank samples in onsite transfer cask, receipt and inspection of SST samples, receipt and extrusion of core samples at 325A shielded facility, cleaning and shipping of waste tank samplers, homogenization of solutions/slurries/sludges, and test sample preparation for bioassay quality control program.« less

Quantitative analysis of three chiral pesticide enantiomers by high-performance column liquid chromatography.

PubMed

Wang, Peng; Liu, Donghui; Gu, Xu; Jiang, Shuren; Zhou, Zhiqiang

2008-01-01

Methods for the enantiomeric quantitative determination of 3 chiral pesticides, paclobutrazol, myclobutanil, and uniconazole, and their residues in soil and water are reported. An effective chiral high-performance liquid chromatographic (HPLC)-UV method using an amylose-tris(3,5-dimethylphenylcarbamate; AD) column was developed for resolving the enantiomers and quantitative determination. The enantiomers were identified by a circular dichroism detector. Validation involved complete resolution of each of the 2 enantiomers, plus determination of linearity, precision, and limit of detection (LOD). The pesticide enantiomers were isolated by solvent extraction from soil and C18 solid-phase extraction from water. The 2 enantiomers of the 3 pesticides could be completely separated on the AD column using n-hexane isopropanol mobile phase. The linearity and precision results indicated that the method was reliable for the quantitative analysis of the enantiomers. LODs were 0.025, 0.05, and 0.05 mg/kg for each enantiomer of paclobutrazol, myclobutanil, and uniconazole, respectively. Recovery and precision data showed that the pretreatment procedures were satisfactory for enantiomer extraction and cleanup. This method can be used for optical purity determination of technical material and analysis of environmental residues.

Supported liquid membrane-liquid chromatography-mass spectrometry analysis of cyanobacterial toxins in fresh water systems

NASA Astrophysics Data System (ADS)

Mbukwa, Elbert A.; Msagati, Titus A. M.; Mamba, Bhekie B.

Harmful algal blooms (HABs) are increasingly becoming of great concern to water resources worldwide due to indiscriminate waste disposal habits resulting in water pollution and eutrophication. When cyanobacterial cells lyse (burst) they release toxins called microcystins (MCs) that are well known for their hepatotoxicity (causing liver damage) and have been found in eutrophic lakes, rivers, wastewater ponds and other water reservoirs. Prolonged exposure to low concentrated MCs are equally of health importance as they are known to be bioaccumulative and even at such low concentration do exhibit toxic effects to aquatic animals, wildlife and human liver cells. The application of common treatment processes for drinking water sourced from HABs infested reservoirs have the potential to cause algal cell lyses releasing low to higher amounts of MCs in finished water. Trace microcystins in water/tissue can be analyzed and quantified using Liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) following solid-phase extraction (SPE) sample clean-up procedures. However, extracting MCs from algal samples which are rich in chlorophyll pigments and other organic matrices the SPE method suffers a number of drawbacks, including cartridge clogging, long procedural steps and use of larger volumes of extraction solvents. We applied a supported liquid membrane (SLM) based technique as an alternative sample clean-up method for LC-ESI-MS analysis of MCs from both water and algal cells. Four (4) MC variants (MC-RR, -YR, -LR and -WR) from lyophilized cells of Microcystis aeruginosa and water collected from a wastewater pond were identified) and quantified using LC-ESI-MS following a SLM extraction and liquid partitioning step, however, MC-WR was not detected from water extracts. Within 45 min of SLM extraction all studied MCs were extracted and pre-concentrated in approximately 15 μL of an acceptor phase at an optimal pH 2.02 of the donor phase (sample). The highest total quantifiable intracellular and extracellular MCs were 37.039 ± 0.087 μg/g DW and 5.123 ± 0.018 μg/L, respectively. The concentrations of MC-RR were the highest from all samples studied recording maximum values of 21.579 ± 0.066 μg/g DW and 3.199 ± 0.012 μg/L for intracellular and extracellular quantities, respectively.

Vortex-homogenized matrix solid-phase dispersion for the extraction of short chain chlorinated paraffins from indoor dust samples.

PubMed

Chen, Yu-Hsuan; Chang, Chia-Yu; Ding, Wang-Hsien

2016-11-11

A simple and effective method for determining short chain chlorinated paraffins (SCCPs) in indoor dust is presented. The method employed a modified vortex-homogenized matrix solid-phase dispersion (VH-MSPD) prior to its detection by gas chromatography - electron-capture negative-ion mass spectrometry (GC-ECNI-MS) operating in the selected-ion-monitoring (SIM) mode. Under the best extraction conditions, 0.1-g of dust sample was dispersed with 0.1-g of silica gel by using vortex (2min) instead of using a mortar and pestle (3min). After that step, the blend was transferred to a glass column containing 3-g acidic silica gel, 2-g basic silica gel, and 2-g of deactivated silica gel, used as clean-up co-sorbents. Then, target analytes were eluted with 5mL of n-hexane/dichloromethane (2:1, v/v) mixture. The extract was evaporated to dryness under a gentle stream of nitrogen. The residue was then re-dissolved in n-hexane (10μL), and subjected to GC-ECNI-MS analysis. The limits of quantitation (LOQs) ranged from 0.06 to 0.25μg/g for each SCCP congener. Precision was less than 7% for both intra- and inter-day analysis. Trueness was above 89%, which was calculated by mean extraction recovery. The VH-MSPD combined with GC-ECNI-MS was successfully applied to quantitatively detect SCCPs from various indoor dust samples, and the concentrations ranged from 1.2 to 31.2μg/g. Copyright © 2016 Elsevier B.V. All rights reserved.

Development of multiclass methods for drug residues in eggs: hydrophilic solid-phase extraction cleanup and liquid chromatography/tandem mass spectrometry analysis of tetracycline, fluoroquinolone, sulfonamide, and beta-lactam residues.

PubMed

Heller, David N; Nochetto, Cristina B; Rummel, Nathan G; Thomas, Michael H

2006-07-26

A method was developed for detection of a variety of polar drug residues in eggs via liquid chromatography/tandem mass spectrometry (LC/MS/MS) with electrospray ionization (ESI). A total of twenty-nine target analytes from four drug classes-sulfonamides, tetracyclines, fluoroquinolones, and beta-lactams-were extracted from eggs using a hydrophilic-lipophilic balance polymer solid-phase extraction (SPE) cartridge. The extraction technique was developed for use at a target concentration of 100 ng/mL (ppb), and it was applied to eggs containing incurred residues from dosed laying hens. The ESI source was tuned using a single, generic set of tuning parameters, and analytes were separated with a phenyl-bonded silica cartridge column using an LC gradient. In a related study, residues of beta-lactam drugs were not found by LC/MS/MS in eggs from hens dosed orally with beta-lactam drugs. LC/MS/MS performance was evaluated on two generations of ion trap mass spectrometers, and key operational parameters were identified for each instrument. The ion trap acquisition methods could be set up for screening (a single product ion) or confirmation (multiple product ions). The lower limit of detection for screening purposes was 10-50 ppb (sulfonamides), 10-20 ppb (fluoroquinolones), and 10-50 ppb (tetracyclines), depending on the drug, instrument, and acquisition method. Development of this method demonstrates the feasibility of generic SPE, LC, and MS conditions for multiclass LC/MS residue screening.

Analysis of multi-class preservatives in leave-on and rinse-off cosmetics by matrix solid-phase dispersion.

PubMed

Sanchez-Prado, Lucia; Alvarez-Rivera, Gerardo; Lamas, J Pablo; Lores, Marta; Garcia-Jares, Carmen; Llompart, Maria

2011-12-01

Matrix solid-phase extraction has been successfully applied for the determination of multi-class preservatives in a wide variety of cosmetic samples including rinse-off and leave-on products. After extraction, derivatization with acetic anhydride, and gas chromatography-mass spectrometry analysis were performed. Optimization studies were done on real non-spiked and spiked leave-on and rinse-off cosmetic samples. The selection of the most suitable extraction conditions was made using statistical tools such as ANOVA, as well as factorial experimental designs. The final optimized conditions were common for both groups of cosmetics and included the dispersion of the sample with Florisil (1:4), and the elution of the MSPD column with 5 mL of hexane/acetone (1:1). After derivatization, the extract was analyzed without any further clean-up or concentration step. Accuracy, precision, linearity and detection limits were evaluated to assess the performance of the proposed method. The recovery studies on leave-on and rinse-off cosmetics gave satisfactory values (>78% for all analytes in all the samples) with an average relative standard deviation value of 4.2%. The quantification limits were well below those set by the international cosmetic regulations, making this multi-component analytical method suitable for routine control. The analysis of a broad range of cosmetics including body milk, moisturizing creams, anti-stretch marks creams, hand creams, deodorant, shampoos, liquid soaps, makeup, sun milk, hand soaps, among others, demonstrated the high use of most of the target preservatives, especially butylated hydroxytoluene, methylparaben, propylparaben, and butylparaben.

Gas chromatography with pulsed flame photometric detection multiresidue method for organophosphate pesticide and metabolite residues at the parts-per-billion level in representatives commodities of fruits and vegetable crop groups.

PubMed

Podhorniak, L V; Negron, J F; Griffith, F D

2001-01-01

A gas chromatographic method with a pulsed flame photometric detector (P-FPD) is presented for the analysis of 28 parent organophosphate (OP) pesticides and their OP metabolites. A total of 57 organophosphates were analyzed in 10 representative fruit and vegetable crop groups. The method is based on a judicious selection of known procedures from FDA sources such as the Pesticide Analytical Manual and Laboratory Information Bulletins, combined in a manner to recover the OPs and their metabolite(s) at the part-per-billion (ppb) level. The method uses an acetone extraction with either miniaturized Hydromatrix column partitioning or alternately a miniaturized methylene dichloride liquid-liquid partitioning, followed by solid-phase extraction (SPE) cleanup with graphitized carbon black (GCB) and PSA cartridges. Determination of residues is by programmed temperature capillary column gas chromatography fitted with a P-FPD set in the phosphorus mode. The method is designed so that a set of samples can be prepared in 1 working day for overnight instrumental analysis. The recovery data indicates that a daily column-cutting procedure used in combination with the SPE extract cleanup effectively reduces matrix enhancement at the ppb level for many organophosphates. The OPs most susceptible to elevated recoveries around or greater than 150%, based on peak area calculations, were trichlorfon, phosmet, and the metabolites of dimethoate, fenamiphos, fenthion, and phorate.

Method development for the analysis of ionophore antimicrobials in dairy manure to assess removal within a membrane-based treatment system.

PubMed

Hurst, Jerod J; Wallace, Josh S; Aga, Diana S

2018-04-01

Ionophore antimicrobials are heavily used in the livestock industries, both for preventing animal infection by coccidia protozoa and for increasing feed efficiency. Ionophores are excreted mostly unmetabolized and are released into the environment when manure is land-applied to fertilize croplands. Here, an analytical method was optimized to study the occurrences of five ionophore residues (monensin, lasalocid, maduramycin, salinomycin, and narasin) in dairy manure after solid-liquid separation and further treatment of the liquid manure by a membrane-based treatment system. Ionophore residues from the separated solid manure (dewatered manure) and suspended solids of manure slurry samples were extracted using ultrasonication with methanol, followed by sample clean-up using solid phase extraction (SPE) and subsequent analysis via liquid chromatography-tandem mass spectrometry (LC-MS/MS). The use of an ethyl acetate and methanol (1:1 v:v) mixture as an SPE eluent resulted in higher recoveries and lower method quantitation limits (MQL), when compared to using methanol. Overall recoveries from separated solid manure ranged from 73 to 134%. Liquid manure fractions were diluted with Nanopure™ water and cleaned up using SPE, where recoveries ranged from 51 to 100%. The developed extraction and LC-MS/MS methods were applied to analyze dairy manure samples subjected to an advanced manure treatment process involving a membrane-based filtration step (reverse osmosis). Monensin and lasalocid were detected at higher concentrations in the suspended solid fractions (4.40-420 ng/g for lasalocid and 85-1950 ng/g for monensin) compared to the liquid fractions (

Multi-contaminant analysis of organophosphate and halogenated flame retardants in food matrices using ultrasonication and vacuum assisted extraction, multi-stage cleanup and gas chromatography-mass spectrometry.

PubMed

Xu, Fuchao; García-Bermejo, Ángel; Malarvannan, Govindan; Gómara, Belén; Neels, Hugo; Covaci, Adrian

2015-07-03

A multi-residue analytical method was developed for the determination of a range of flame retardants (FRs), including polybrominated diphenyl ethers (PBDEs), emerging halogenated FRs (EFRs) and organophosphate FRs (PFRs), in food matrices. An ultrasonication and vacuum assisted extraction (UVAE), followed by a multi-stage clean-up procedure, enabled the removal of up to 1g of lipid from 2.5 g of freeze-dried food samples and significantly reduce matrix effects. UVAE achieves a waste factor (WF) of about 10%, while the WFs of classical QuEChERS methods range usually between 50 and 90%. The low WF of UVAE leads to a dramatic improvement in the sensitivity along with saving up to 90% of spiking (internal) standards. Moreover, a two-stage clean-up on Florisil and aminopropyl silica was introduced after UVAE, for an efficient removal of pigments and residual lipids, which led to cleaner extracts than normally achieved by dispersive solid phase extraction (d-SPE). In this way, the extracts could be concentrated to low volumes, e.g. <100 μL and the equivalent matrix concentrations were up to 100g ww/mL. The final analysis of PFRs was performed on GC-EI-MS, while PBDEs and EFRs were measured by GC-ECNI-MS. Validation tests were performed with three food matrices (lean beef, whole chicken egg and salmon filet), obtaining acceptable recoveries (66-135%) with good repeatability (RSD 1-24%, mean 7%). Method LOQs ranged between 0.008 and 0.04 ng/g dw for PBDEs, between 0.08 and 0.20 ng/g dw for EFRs, and between 1.4 and 3.6 ng/g dw for PFRs. The method was further applied to eight types of food samples (including meat, eggs, fish, and seafood) with lipid contents ranging from 0.1 to 22%. Various FRs were detected above MLOQ levels, demonstrating the wide-range applicability of our method. To the best of our knowledge, this is the first method reported for simultaneous analysis of brominated and organophosphate FRs in food matrices. Copyright © 2015 Elsevier B.V. All rights reserved.

Liquid chromatography mass spectrometry determination of perfluoroalkyl acids in environmental solid extracts after phospholipid removal and on-line turbulent flow chromatography purification.

PubMed

Mazzoni, M; Polesello, S; Rusconi, M; Valsecchi, S

2016-07-01

An on-line TFC (Turbulent Flow Chromatography) clean up procedures coupled with UHPLC-MS/MS (Ultra High Performance Liquid Chromatography Mass Spectrometry) multi-residue method was developed for the simultaneous determination of 8 perfluroalkyl carboxylic acids (PFCA, from 5 to 12 carbon atoms) and 3 perfluoroalkyl sulfonic acids (PFSA, from 4 to 8 carbon atoms) in environmental solid matrices. Fast sample preparation procedure was based on a sonication-assisted extraction with acetonitrile. Phospholipids in biological samples were fully removed by an off-line SPE purification before injection, using HybridSPE(®) Phospholipid Ultra cartridges. The development of the on-line TFC clean-up procedure regarded the choice of the stationary phase, the optimization of the mobile phase composition, flow rate and injected volume. The validation of the optimized method included the evaluation of matrix effects, accuracy and reproducibility. Signal suppression in the analysis of fortified extracts ranged from 1 to 60%, and this problem was overcome by using isotopic dilution. Since no certified reference materials were available for PFAS in these matrices, accuracy was evaluated by recoveries on spiked clam samples which were 98-133% for PFCAs and 40-60% for PFSAs. MLDs and MLQs ranged from 0.03 to 0.3ngg(-1) wet weight and from 0.1 to 0.9ngg(-1) wet weight respectively. Repeatability (intra-day precision) and reproducibility (inter-day precision) showed RSD from 3 to 13% and from 4 to 27% respectively. Validated on-line TFC/UHPLC-MS/MS method has been applied for the determination of perfluoroalkyl acids in different solid matrices (sediment, fish, bivalves and bird yolk). Copyright © 2016 Elsevier B.V. All rights reserved.

A simple and highly selective molecular imprinting polymer-based methodology for propylparaben monitoring in personal care products and industrial waste waters.

PubMed

Vicario, Ana; Aragón, Leslie; Wang, Chien C; Bertolino, Franco; Gomez, María R

2018-02-05

In this work, a novel molecularly imprinted polymer (MIP) proposed as solid phase extraction sorbent was developed for the determination of propylparaben (PP) in diverse cosmetic samples. The use of parabens (PAs) is authorized by regulatory agencies as microbiological preservative; however, recently several studies claim that large-scale use of these preservatives can be a potential health risk and harmful to the environment. Diverse factors that influence on polymer synthesis were studied, including template, functional monomer, porogen and crosslinker used. Morphological characterization of the MIP was performed using SEM and BET analysis. Parameters affecting the molecularly imprinted solid phase extraction (MISPE) and elution efficiency of PP were evaluated. After sample clean-up, the analyte was analyzed by high performance liquid chromatography (HPLC). The whole procedure was validated, showing satisfactory analytical parameters. After applying the MISPE methodology, the extraction recoveries were always better than 86.15%; the obtained precision expressed as RSD% was always lower than 2.19 for the corrected peak areas. Good linear relationship was obtained within the range 8-500ngmL -1 of PP, r 2 =0.99985. Lower limits of detection and quantification after MISPE procedure of 2.4 and 8ngmL -1 , respectively were reached, in comparison with previously reported methodologies. The development of MISPE-HPLC methodology provided a simple an economic way for accomplishing a clean-up/preconcentration step and the subsequent determination of PP in a complex matrix. The performance of the proposed method was compared against C-18 and silica solid phase extraction (SPE) cartridges. The recovery factors obtained after applying extraction methods were 96.6, 64.8 and 0.79 for MISPE, C18-SPE and silica-SPE procedures, respectively. The proposed methodology improves the retention capability of SPE material plus robustness and possibility of reutilization, enabling it to be used for PP routine monitoring in diverse personal care products (PCP) and environmental samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Determination of 24 personal care products in fish bile using hybrid solvent precipitation and dispersive solid phase extraction cleanup with ultrahigh performance liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry.

PubMed

Yao, Li; Lv, Yin-Zhi; Zhang, Li-Juan; Liu, Wang-Rong; Zhao, Jian-Liang; Liu, You-Sheng; Zhang, Qian-Qian; Ying, Guang-Guo

2018-05-25

Personal care products (PCPs) are ubiquitous in aquatic environments owing to the continuous discharge of domestic wastewater from highly urbanized regions. These PCPs can be adsorbed by fish and thereafter usually enter the bile of the fish through biliary excretion. In this study, a sensitive method based on a combination of hybrid solvent precipitation and dispersive solid phase extraction (d-SPE) purification was developed to simultaneously extract and detect 24 PCPs, namely, 16 biocides, 4 synthetic musks, and 4 benzotriazoles, from fish bile. Hybrid precipitation on solid phase extraction (SPE) tubes was applied to remove phospholipids and proteins, and a d-SPE procedure was used for further purification. The extraction solvents for the hybrid precipitation/SPE tubes and d-SPE materials were optimized. The method performance for bile samples both with and without enzyme hydrolysis using β-glucuronidase/aryl-sulfatase were validated. The 24 PCPs in fish bile were spiked with standard concentrations of 10 ng/mL, 20 ng/mL, 100 ng/mL, and 200 ng/mL to evaluate recoveries, which ranged from 70 to 120% for 16, 16, 22, and 21 analytes with hydrolysis, respectively, and 70-120% for 14, 15, 23, and 23 analytes without hydrolysis, respectively. The quantification limits for target PCPs were in the range 0.26-7.38 ng/mL [excluding musk xylene (MX) and musk ketone (MK)] and 0.20-9.48 ng/mL (excluding MX and MK) for bile samples with and without enzyme hydrolysis, respectively. After enzyme hydrolysis, 12 PCPs were detected in bile from fish collected from the Yangtze River, with a maximum detected concentration of 460 ng/mL, for triclosan (TCS). The hydrolysis reaction indicated that high percentages of glucuronide and sulfate metabolites for some PCPs, i.e. four parabens and TCS, existed in the bile. Copyright © 2018 Elsevier B.V. All rights reserved.

Determination of pyrethrin and pyrethroid residues in animal fat using liquid chromatography coupled to tandem mass spectrometry.

PubMed

Moloney, M; Tuck, S; Ramkumar, A; Furey, A; Danaher, M

2018-03-01

A method was developed for the confirmatory and quantitative analysis of one pyrethrin and 18 pyrethroid residues in animal fat. Fat was extracted was collected from adipose tissue melted in an oven at 65 °C for 2 h. Fat samples (1 g) were dispersed with deactivated Florisil ® sorbent and extracted with MeCN. Sample extracts were purified by cold temperature precipitation at -30 °C for 4 h and further purified using dispersive solid-phase extraction (d-SPE) clean-up in tubes containing 500 mg of Z-SEP+ and 125 mg of PSA bonded silica. Purified samples were analysed by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) detection. Chromatographic separation was carried out on a Acquity C 8 BEH column, using a binary gradient separation comprising of mobile phase A, 5 mM ammonium formate in water:MeOH (80:20, v/v,) and mobile phase B, 5 mM ammonium formate in MeOH. The mass spectrometer was operated in the positive electrospray ionisation mode (ESI(+)). Validation was performed following the 2002/657/EC guidelines. Trueness ranged between 84% and 143% and precision ranged between 3.9% and 29%. The developed method is particularly advantageous because the sample preparation procedure does not require complex sample extraction equipment and uses less solvent compared to other sample preparation protocols. Copyright © 2017 Elsevier B.V. All rights reserved.

Determination of Aconitum Alkaloids in Dietary Supplements and Raw Botanical Materials by Liquid Chromatography/UV Detection with Confirmation by Liquid Chromatography/Tandem Mass Spectrometry: Collaborative Study

PubMed Central

Wong, Siu-Kay

2010-01-01

An interlaboratory study was conducted to evaluate a method for the determination of 3 Aconitum alkaloids, viz., aconitine, mesaconitine, and hypaconitine, in raw botanical material and dietary supplements. The alkaloids were extracted with diethyl ether in the presence of ammonia. After cleanup by solid-phase extraction to remove matrix interferences, the alkaloids were determined by reversed-phase liquid chromatography (LC)/UV detection at 235 nm with confirmation by LC/tandem mass spectrometry (MS/MS). A total of 14 blind duplicates were successfully analyzed by 12 collaborators. For repeatability, the relative standard deviation (RSDr) values ranged from 1.9 to 16.7%, and for reproducibility, the RSDR values ranged from 6.5 to 33%. The HorRat values were all <2 with only one exception at 2.3. All collaborating laboratories had calibration curves with correlation coefficients of >0.998. In addition, 6 collaborators performed the confirmation and were able to verify the identities of the alkaloids by using LC/MS/MS. PMID:19382567

On-line hyphenation of solid-phase extraction to chromatographic separation of sulfonamides with fused-core columns in sequential injection chromatography.

PubMed

Batista, Alex D; Chocholouš, Petr; Satínský, Dalibor; Solich, Petr; Rocha, Fábio R P

2015-02-01

On-line sample pretreatment (clean-up and analyte preconcentration) is for the first time coupled to sequential injection chromatography. The approach combines anion-exchange solid-phase extraction and the highly effective pentafluorophenylpropyl (F5) fused-core particle column for separation of eight sulfonamide antibiotics with similar structures (sulfathiazole, sulfanilamide, sulfacetamide, sulfadiazine, sulfamerazine, sulfadimidine, sulfamethoxazole and sulfadimethoxine). The stationary phase was selected after a critical comparison of the performance achieved by three fused-core reversed phase columns (Ascentis(®) Express RP-Amide, Phenyl-Hexyl, and F5) and two monolithic columns (Chromolith(®) High Resolution RP-18 and CN). Acetonitrile and acetate buffer pH 5.0 at 0.60 mL min(-1) were used as mobile phase to perform the separations before spectrophotometric detection. The first mobile phase was successfully used as eluent from SPE column ensuring transfer of a narrow zone to the chromatographic column. Enrichment factors up to 39.2 were achieved with a 500 µL sample volume. The developed procedure showed analysis time <10.5 min, resolutions >1.83 with peak symmetry ≤1.52, LODs between 4.9 and 27 µg L(-1), linear response ranges from 30.0 to 1000.0 µg L(-1) (r(2)>0.996) and RSDs of peak heights <2.9% (n=6) at a 100 µg L(-1) level and enabled the screening control of freshwater samples contaminated at the 100 µg L(-1) level. The proposed approach expanded the analytical potentiality of SIC and avoided the time-consuming batch sample pretreatment step, thus minimizing risks of sample contamination and analyte losses. Copyright © 2014 Elsevier B.V. All rights reserved.

Determination of chemotherapeutic agents in fish and shellfish by matrix solid-phase dispersion and liquid chromatography-tandem mass spectrometry.

PubMed

Carro, Antonia M; García-Rodríguez, Diego; Gonzalez-Siso, Paula; Lorenzo, Rosa A

2012-11-01

Chemicals are widely used in aquaculture and one of the main recipients of these analytes is the aquatic environment. The aim of this work was to develop and validate a simple and sensitive method for the determination of multiclass chemotherapeutic agents in farmed fish and shellfish using matrix solid-phase dispersion and liquid chromatography-tandem mass spectrometry. Residues of azamethiphos, three avermectins, two carbamates, and two benzoylureas were extracted from samples using silica gel as clean-up adsorbent and 0.5% acetic acid in acetonitrile as elution solvent. The extraction conditions were investigated and optimized using an experimental design. Mass spectrometry detection was carried out in positive electrospray ionization mode with multiple-reaction monitoring scan (except for benzoylurea family). Matrix-matched standards were used for the drugs quantification. Good linearity (R(2) ≥ 0.996) was observed in the range of 5-500 μg kg(-1). Limits of detection were in the range of 1.5-3.7 μg kg(-1). Recoveries from salmon samples spiked with veterinary drugs were in the range 84.9-118%. Precision was satisfactory since relative standard deviations were lower than 10.6%. The method can be successfully applied for the analysis of fish and shellfish from aquaculture. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of polychlorinated biphenyls in transformer oil using various adsorbents for solid phase extraction.

PubMed

Na, Yun-Cheol; Kim, Kang-Jin; Hong, Jongki; Seo, Jung-Ju

2008-08-01

Various adsorbents for a solid phase extraction (SPE) method were used to study their ability to separate PCBs from transformer oil to rapidly determine their sub-ppm concentration in the transformer oil. Approximately 90% of the transformer oil could be removed from the PCBs by using a hydrophilic-lipophilic balanced copolymer (HLB) adsorbent, but the recovery of deca-chlorobiphenyl (deca-CB) used as a surrogate was only 24.5% due to lose during this cleanup process. The use of a silica adsorbent gave good results with 89.9% recovery of the deca-CB. The recovery of Aroclor 1242 and 1260 were 95.4 and 90.3% on silica, and 98.9 and 83.5% on HLB, respectively. Acid treatment was an essential step in removing the ambiguous interference peaks to help identify the PCBs. A decreased sensitivity of the electron capture detection (ECD) for PCBs was observed due to the presence of the remaining trace oil after the workup procedure. This loss in sensitivity was allowed for by using tetrachloroxylene as an internal standard, and this was found to be reliable for the criteria of quality control by employing an experiment in which LCS was spiked with 2mg/l of Aroclor 1260 and analyzed each day over a 25 day period. The MDL for the analytical method established in this study is 0.05 mg/l.

Fully automated analysis of four tobacco-specific N-nitrosamines in mainstream cigarette smoke using two-dimensional online solid phase extraction combined with liquid chromatography-tandem mass spectrometry.

PubMed

Zhang, Jie; Bai, Ruoshi; Yi, Xiaoli; Yang, Zhendong; Liu, Xingyu; Zhou, Jun; Liang, Wei

2016-01-01

A fully automated method for the detection of four tobacco-specific nitrosamines (TSNAs) in mainstream cigarette smoke (MSS) has been developed. The new developed method is based on two-dimensional online solid-phase extraction-liquid chromatography-tandem mass spectrometry (SPE/LC-MS/MS). The two dimensional SPE was performed in the method utilizing two cartridges with different extraction mechanisms to cleanup disturbances of different polarity to minimize sample matrix effects on each analyte. Chromatographic separation was achieved using a UPLC C18 reversed phase analytical column. Under the optimum online SPE/LC-MS/MS conditions, N'-nitrosonornicotine (NNN), N'-nitrosoanatabine (NAT), N'-nitrosoanabasine (NAB), and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) were baseline separated with good peak shapes. This method appears to be the most sensitive method yet reported for determination of TSNAs in mainstream cigarette smoke. The limits of quantification for NNN, NNK, NAT and NAB reached the levels of 6.0, 1.0, 3.0 and 0.6 pg/cig, respectively, which were well below the lowest levels of TSNAs in MSS of current commercial cigarettes. The accuracy of the measurement of four TSNAs was from 92.8 to 107.3%. The relative standard deviations of intra-and inter-day analysis were less than 5.4% and 7.5%, respectively. The main advantages of the method developed are fairly high sensitivity, selectivity and accuracy of results, minimum sample pre-treatment, full automation, and high throughput. As a part of the validation procedure, the developed method was applied to evaluate TSNAs yields for 27 top-selling commercial cigarettes in China. Copyright © 2015 Elsevier B.V. All rights reserved.

Rapid determination of chlormequat in meat by dispersive solid-phase extraction and hydrophilic interaction liquid chromatography (HILIC)-electrospray tandem mass spectrometry.

PubMed

Li, Chunmei; Jin, Fen; Yu, Zhiyong; Qi, Yamei; Shi, Xiaomei; Wang, Miao; Shao, Hua; Jin, Maojun; Wang, Jing; Yang, Mingqi

2012-07-11

A rapid method for analyzing trace levels of chlormequat (CQ) in meat samples by hydrophilic interaction liquid chromatography (HILIC)-electrospray tandem mass spectrometry was developed. The samples were extracted with acetonitrile, followed by a rapid cleanup through a dispersive solid-phase extraction (DSPE) technique with octadecyl (C18) DSPE sorbents. The chromatographic separation was achieved within 6 min using a HILIC column with 10 mM ammonium acetate and 0.1% (v/v) formic acid in water/acetonitrile (v/v, 40:60) as the mobile phase. Quantification was performed using a matrix-matched calibration curve, which was linear in the range of the 0.05-100 μg/L. The limit of detection (LOD) was estimated at 0.03 μg/kg for CQ on the basis of a peak to peak signal noise (S/N = 3). The limit of quantification (LOQ) was 0.1 μg/kg on the basis of the lowest spiked concentration with suitable precision and accuracy. The average recovery of CQ in spiked meat samples was 86.4-94.7% at 2, 20, and 200 μg/kg. Finally, this method was applied to determine CQ in the livestock and poultry meats purchased from markets in Beijing in 2011. CQ was detected in all 12 samples, and the concentration was 0.4-636.0 μg/kg. Concentrations in a chicken sample (636.0 μg/kg) and a goat meat sample (486.0 μg/kg) were found to be 15.9 and 2.43 times the corresponding Codex maximum residue limits, respectively.

Rapid screening of methamphetamines in human serum by headspace solid-phase microextraction using a dodecylsulfate-doped polypyrrole film coupled to ion mobility spectrometry.

PubMed

Alizadeh, Naader; Mohammadi, Abdorreza; Tabrizchi, Mahmoud

2008-03-07

A simple, rapid and highly sensitive method for simultaneous analysis of methamphetamine (MA) and 3,4-methylenedioxy methamphetamine (MDMA) in human serum was developed using the solid-phase microextraction (SPME) combined with ion mobility spectrometry (IMS). A dodecylsulfate-doped polypyrrole (PPy-DS) was applied as a new fiber for SPME. Electrochemically polymerized PPy is formed on the surface of a platinum wire and will contain charge-compensating anion (dodecylsulfate) incorporated during synthesis using cyclic voltammetry (CV) technique. The extraction properties of the fiber to MA and MDMA were examined, using a headspace-SPME (HS-SPME) device and thermal desorption in injection port of IMS. The results show that PPy-DS as a SPME fiber coating is suitable for the successful extraction of these compounds. This method is suitable for the identification and determination of MAs, is not time-consuming, requires small quantities of sample and does not require any derivatization. Parameters like pH, extraction time, ionic strength, and temperature of the sample were studied and optimized to obtain the best extraction results. The HS-SPME-IMS method provided good repeatability (RSDs<7.8 %) for spiked serum samples. The calibration graphs were linear in the range of 20-4000 ng ml(-1) (R(2)>0.99) and detection limits for MDMA and MA were 5 and 8 ng ml(-1), respectively. HS-SPME-IMS of non-spiked serum sample provided a spectrum without any peak from the matrix, supporting an effective sample clean-up. Finally, the proposed method was applied for analysis one of the ecstasy tablet.

Comparison of veterinary drug residue results in animal tissues by ultrahigh-performance liquid chromatography coupled to triple quadrupole or quadrupole-time-of-flight tandem mass spectrometry after different sample preparation methods, including use of a commercial lipid removal product.

PubMed

Anumol, Tarun; Lehotay, Steven J; Stevens, Joan; Zweigenbaum, Jerry

2017-04-01

Veterinary drug residues in animal-derived foods must be monitored to ensure food safety, verify proper veterinary practices, enforce legal limits in domestic and imported foods, and for other purposes. A common goal in drug residue analysis in foods is to achieve acceptable monitoring results for as many analytes as possible, with higher priority given to the drugs of most concern, in an efficient and robust manner. The U.S. Department of Agriculture has implemented a multiclass, multi-residue method based on sample preparation using dispersive solid phase extraction (d-SPE) for cleanup and ultrahigh-performance liquid chromatography-tandem quadrupole mass spectrometry (UHPLC-QQQ) for analysis of >120 drugs at regulatory levels of concern in animal tissues. Recently, a new cleanup product called "enhanced matrix removal for lipids" (EMR-L) was commercially introduced that used a unique chemical mechanism to remove lipids from extracts. Furthermore, high-resolution quadrupole-time-of-flight (Q/TOF) for (U)HPLC detection often yields higher selectivity than targeted QQQ analyzers while allowing retroactive processing of samples for other contaminants. In this study, the use of both d-SPE and EMR-L sample preparation and UHPLC-QQQ and UHPLC-Q/TOF analysis methods for shared spiked samples of bovine muscle, kidney, and liver was compared. The results showed that the EMR-L method provided cleaner extracts overall and improved results for several anthelmintics and tranquilizers compared to the d-SPE method, but the EMR-L method gave lower recoveries for certain β-lactam antibiotics. QQQ vs. Q/TOF detection showed similar mixed performance advantages depending on analytes and matrix interferences, with an advantage to Q/TOF for greater possible analytical scope and non-targeted data collection. Either combination of approaches may be used to meet monitoring purposes, with an edge in efficiency to d-SPE, but greater instrument robustness and less matrix effects when analyzing EMR-L extracts. Graphical abstract Comparison of cleanup methods in the analysis of veterinary drug residues in bovine tissues.

Screening and confirmation of steroids and nitroimidazoles in urine, blood, and food matrices: Sample preparation methods and liquid chromatography tandem mass spectrometric separations.

PubMed

Tölgyesi, Ádám; Barta, Enikő; Simon, Andrea; McDonald, Thomas J; Sharma, Virender K

2017-10-25

Veterinary drugs containing synthetic anabolic steroid and nitroimidazole active agents are not allowed for their applications in livestock of the European Union (EU). This paper presents analyses of twelve selected steroids and six nitroimidazole antibiotics at low levels (1.56μg/L-4.95μg/L and 0.17μg/kg-2.14μg/kg, respectively) in body fluids and egg incurred samples. Analyses involved clean-up procedures, high performance liquid chromatography (HPLC) separation, and tandem mass spectrometric screening and confirmatory methods. Target steroids and nitroimidazoles in samples were cleaned by two independent supported liquid extraction and solid phase extraction procedures. Separation of the selected compounds was conducted on Kinetex XB C-18 HPLC column using gradient elution. The screening methods utilised supported liquid extraction that enabled fast and cost effective clean-up. The confirmatory methods were improved by extending the number of matrices and compounds, and by introducing an isotope dilution mass spectrometry for nitroimidazoles. The new methods were validated according to the recommendation of the European Union Reference Laboratories and the performance characteristics evaluated met fully the criteria. The methods were applied to incurred samples in the proficiency tests. The obtained results of Z-scores demonstrated the applicability of developed protocols of the methods to real samples. The confirmatory methods were applied to the national monitoring program and natural contamination of prednisolone could be detected in urine at low concentration in few samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Preparation of a hollow porous molecularly imprinted polymer using tetrabromobisphenol A as a dummy template and its application as SPE sorbent for determination of bisphenol A in tap water.

PubMed

Li, Jin; Zhang, Xuebin; Liu, Yuxin; Tong, Hongwu; Xu, Yeping; Liu, Shaomin

2013-12-15

In this paper, a highly selective sample cleanup procedure combing dummy molecular imprinting and solid-phase extraction (DMIP-SPE) was developed for the isolation and determination of bisphenol A (BPA) in tap water. The novel hollow porous dummy molecularly imprinted polymer (HPDMIP) was prepared adopting a sacrificial support approach, using tetrabromobisphenol A (TBBPA), whose structure was similar to that of BPA, as the dummy template and mesoporous MCM-48 nanospheres as the support. Owing to a very short distance between the binding sites and the surface, a large surface area and a good steric structure to match its imprint molecules, the maximum adsorption capacities (Qmax) of the dummy-imprinted and non-imprinted sorbents for BPA were as high as 445 and 340 μmol g(-1), respectively, and the adsorption reached about 73% of Qmax in 10 min. Meanwhile, a method was developed for the determination of BPA using HPDMIP as a solid-phase extraction enrichment sorbent coupled with HPLC. Under the optimum experimental conditions, HPDMIP exhibited satisfactory results in the enrichment and determination of BPA in tap water with a recovery rate of 95-105%, and relative standard deviations of below 6%, and it can achieve a limit of detection as low as 3 ng mL(-1). The developed extraction protocol eliminated the effect of template leakage on quantitative analysis and could be applied for the determination of BPA in complicated functional samples. © 2013 Elsevier B.V. All rights reserved.

Molecularly imprinted polymer microspheres prepared by Pickering emulsion polymerization for selective solid-phase extraction of eight bisphenols from human urine samples.

PubMed

Yang, Jiajia; Li, Yun; Wang, Jincheng; Sun, Xiaoli; Cao, Rong; Sun, Hao; Huang, Chaonan; Chen, Jiping

2015-05-04

The bisphenol A (BPA) imprinted polymer microspheres were prepared by simple Pickering emulsion polymerization. Compared to traditional bulk polymerization, both high yields of polymer and good control of particle sizes were achieved. The characterization results of scanning electron microscopy and nitrogen adsorption-desorption measurements showed that the obtained molecularly imprinted polymer microsphere (MIPMS) particles possessed regular spherical shape, narrow diameter distribution (30-60 μm), a specific surface area (S(BET)) of 281.26 m(2) g(-1) and a total pore volume (V(t)) of 0.459 cm(3) g(-1). Good specific adsorption capacity for BPA was obtained in the sorption experiment and good class selectivity for BPA and its seven structural analogs (bisphenol F, bisphenol B, bisphenol E, bisphenol AF, bisphenol S, bisphenol AP and bisphenol Z) was demonstrated by the chromatographic evaluation experiment. The MIPMS as solid-phase extraction (SPE) packing material was then evaluated for extraction and clean-up of these bisphenols (BPs) from human urine samples. An accurate and sensitive analytical method based on the MIPMS-SPE coupled with HPLC-DAD has been successfully established for simultaneous determination of eight BPs from human urine samples with detection limits of 1.2-2.2 ng mL(-1). The recoveries of BPs for urine samples at two spiking levels (100 and 500 ng mL(-1) for each BP) were in the range of 81.3-106.7% with RSD values below 8.3%. Copyright © 2015 Elsevier B.V. All rights reserved.

Determination of limonin in grapefruit juice and other citrus juices by high-performance liquid chromatography.

PubMed

Van Beek, T A; Blaakmeer, A

1989-03-03

A method has been developed for the quantitation of the bitter component limonin in grapefruit juice and other citrus juices. The sample clean-up consisted of centrifugation, filtration and a selective, rapid and reproducible purification with a C2 solid-phase extraction column. The limonin concentration was determined by high-performance liquid chromatography on a C18 column with UV detection at 210 nm. A linear response was obtained from 0.0 to 45 ppm limonin. The minimum detectable amount was 2 ng. The minimum concentration which was detected without concentration with good precision was 0.1 ppm. The method was also used for the determination of limonin in different types of oranges, including navel oranges, mandarins, lemons, limes, pomelos and uglis.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goltz, M.N.; Oxley, M.E.

Aquifer cleanup efforts at contaminated sites frequently involve operation of a system of extraction wells. It has been found that contaminant load discharged by extraction wells typically declines with time, asymptotically approaching a residual level. Such behavior could be due to rate-limited desorption of an organic contaminant from aquifer solids. An analytical model is presented which accounts for rate-limited desorption of an organic solute during cleanup of a contaminated site. Model equations are presented which describe transport of a sorbing contaminant in a converging radial flow field, with sorption described by (1) equilibrium, (2) first-order rate, and (3) Fickian diffusionmore » expressions. The model equations are solved in the Laplace domain and numerically inverted to simulate contaminant concentrations at an extraction well. A Laplace domain solution for the total contaminant mass remaining in the aquifer is also derived. It is shown that rate-limited sorption can have a significant impact upon aquifer remediation. Approximate equivalence among the various rate-limited models is also demonstrated.« less

Refined methodology for the determination of neonicotinoid pesticides and their metabolites in honey bees and bee products by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

PubMed

Kamel, Alaa

2010-05-26

An analytical method was refined for the extraction and determination of neonicotinoid pesticide residues and their metabolites in honey bees and bee products. Samples were extracted with 2% triethylamine (TEA) in acetonitrile (ACN) followed by salting out, solid phase extraction (SPE) cleanup, and detection using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method was validated in triplicate at three fortification concentrations in each matrix. Good recoveries were observed for most analytes and ranged between 70 and 120% with relative standard deviations between replicates of <20% in most cases. The method limits of detection were 0.2 ng/g for the parent neonicotinoid pesticides and ranged between 0.2 and 15 ng/g for the neonicotinoid metabolites. This refined method provides lower detection limits and improved recovery of neonicotinoids and their metabolites, which will help researchers evaluate subchronic effects of these pesticides, address data gaps related to colony collapse disorder (CCD), and determine the role of pesticides in pollinator decline.

Computer-assisted design and synthesis of molecularly imprinted polymers for selective extraction of acetazolamide from human plasma prior to its voltammetric determination.

PubMed

Khodadadian, Mehdi; Ahmadi, Farhad

2010-06-15

Molecularly imprinted polymers (MIPs) were computationally designed and synthesized for the selective extraction of a carbonic anhydrase inhibitor, i.e. acetazolamide (ACZ), from human plasma. Density functional theory (DFT) calculations were performed to study the intermolecular interactions in the pre-polymerization mixture and to find a suitable functional monomer in MIP preparation. The interaction energies were corrected for the basis set superposition error (BSSE) using the counterpoise (CP) correction. The polymerization solvent was simulated by means of polarizable continuum model (PCM). It was found that acrylamide (AAM) is the best candidate to prepare MIPs. To confirm the results of theoretical calculations, three MIPs were synthesized with different functional monomers and evaluated using Langmuir-Freundlich (LF) isotherm. The results indicated that the most homogeneous MIP with the highest number of binding sites is the MIP prepared by AAM. This polymer was then used as a selective adsorbent to develop a molecularly imprinted solid-phase extraction procedure followed by differential pulse voltammetry (MISPE-DPV) for clean-up and determination of ACZ in human plasma.

Determination of alkylphenol and alkylphenolethoxylates in biota by liquid chromatography with detection by tandem mass spectrometry and fluorescence spectroscopy

USGS Publications Warehouse

Schmitz-Afonso, I.; Loyo-Rosales, J.E.; de la Paz Aviles, M.; Rattner, B.A.; Rice, C.P.

2003-01-01

A quantitative method for the simultaneous determination of octylphenol, nonylphenol and the corresponding ethoxylates (1 to 5) in biota is presented. Extraction methods were developed for egg and fish matrices based on accelerated solvent extraction followed by a solid-phase extraction cleanup, using octadecylsilica or aminopropyl cartridges. Identification and quantitation were accomplished by liquid chromatography-electrospray tandem mass spectrometry (LC-MS-MS) and compared to the traditional liquid chromatography with fluorescence spectroscopy detection. LC-MS-MS provides high sensitivity and specificity required for these complex matrices and an accurate quantitation with the use of 13C-labeled internal standards. Quantitation limits by LC-MS-MS ranged from 4 to 12 ng/g in eggs, and from 6 to 22 ng/g in fish samples. These methods were successfully applied to osprey eggs from the Chesapeake Bay and fish from the Great Lakes area. Total levels found in osprey egg samples were up to 18 ng/g wet mass and as high as 8.2 ug/g wet mass in the fish samples.

Analysis of trimethoprim, lincomycin, sulfadoxin and tylosin in swine manure using laser diode thermal desorption-atmospheric pressure chemical ionization-tandem mass spectrometry.

PubMed

Solliec, Morgan; Massé, Daniel; Sauvé, Sébastien

2014-10-01

A new extraction method coupled to a high throughput sample analysis technique was developed for the determination of four veterinary antibiotics. The analytes belong to different groups of antibiotics such as chemotherapeutics, sulfonamides, lincosamides and macrolides. Trimethoprim (TMP), sulfadoxin (SFX), lincomycin (LCM) and tylosin (TYL) were extracted from lyophilized manure using a sonication extraction. McIlvaine buffer and methanol (MeOH) were used as extraction buffers, followed by cation-exchange solid phase extraction (SPE) for clean-up. Analysis was performed by laser diode thermal desorption-atmospheric pressure chemical-ionization (LDTD-APCI) tandem mass spectrometry (MS/MS) with selected reaction monitoring (SRM) detection. The LDTD is a high throughput sample introduction method that reduces total analysis time to less than 15s per sample, compared to minutes when using traditional liquid chromatography (LC). Various SPE parameters were optimized after sample extraction: the stationary phase, the extraction solvent composition, the quantity of sample extracted and sample pH. LDTD parameters were also optimized: solvent deposition, carrier gas, laser power and corona discharge. The method limit of detection (MLD) ranged from 2.5 to 8.3 µg kg(-1) while the method limit of quantification (MLQ) ranged from 8.3 to 28µgkg(-1). Calibration curves in the manure matrix showed good linearity (R(2)≥ 0.996) for all analytes and the interday and intraday coefficients of variation were below 14%. Recoveries of analytes from manure ranged from 53% to 69%. The method was successfully applied to real manure samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Sensitive and selective determination of polycyclic aromatic hydrocarbons in mainstream cigarette smoke using a graphene-coated solid-phase microextraction fiber prior to GC/MS.

PubMed

Wang, Xiaoyu; Wang, Yuan; Qin, Yaqiong; Ding, Li; Chen, Yi; Xie, Fuwei

2015-08-01

A simple method has been developed for the simultaneous determination of 16 polycyclic aromatic hydrocarbons (PAHs) in mainstream cigarette smoke. The procedure is based on employing a homemade graphene-coated solid-phase microextraction (SPME) fiber for extraction prior to GC/MS. In comparison to commercial 100-μm poly(dimethyl siloxane) (PDMS) fiber, the graphene-coated SPME fiber exhibits advantageous cleanup and preconcentration efficiencies. By collecting the particulate phase 5 cigarettes, the LODs and LOQs of 16 target PAHs were 0.02-0.07 and 0.07-0.22 ng/cigarette, respectively, and all of the linear correlation efficiencies were larger than 0.995. The validation results also indicate that the method has good repeatability (RSD between 4.2% and 9.5%) and accuracy (spiked recoveries between 80% and 110%). The developed method was applied to analyze two Kentucky reference cigarettes (1R5F and 3R4F) and six Chinese brands of cigarettes. In addition, the PAH concentrations in the particulate phase of the smoke from the 1R5F Kentucky cigarettes were in good agreement with recently reported results. Due to easy operation and good validation results, this SPME-GC/MS method may be an excellent alternative for trace analysis of PAHs in cigarette smoke. Copyright © 2015 Elsevier B.V. All rights reserved.

Drugs and personal care products as ubiquitous pollutants: occurrence and distribution of clofibric acid, caffeine and DEET in the North Sea.

PubMed

Weigel, Stefan; Kuhlmann, Jan; Hühnerfuss, Heinrich

2002-08-05

An analytical method is presented, which allows the simultaneous extraction of neutral and acidic compounds from 20-L seawater samples at ambient pH (approximately 8.3). It is based on a solid-phase extraction by means of a polystyrene-divinylbenzene sorbent and gas chromatographic-mass spectrometric detection, and provides detection limits in the lower pg/L range. The method was applied to the screening of samples from different North Sea areas for clofibric acid, diclofenac, ibuprofen, ketoprofen, propyphenazone, caffeine and N,N-diethyl-3-toluamide (DEET). Whereas clofibric acid, caffeine and DEET showed to be present throughout the North Sea in concentrations of up to 1.3, 16 and 1.1 ng/L, respectively, propyphenazone could only be detected after further clean-up. Diclofenac and ibuprofen were found in the estuary of the river Elbe (6.2 and 0.6 ng/L, respectively) but in none of the marine samples. Ketoprofen was below the detection limit in all samples.

Hydrophilic Interaction Liquid Chromatography-Tandem Mass Spectrometry Analysis of Fosetyl-Aluminum in Airborne Particulate Matter

PubMed Central

Di Filippo, Patrizia; Riccardi, Carmela; Pomata, Donatella; Marsiglia, Riccardo; Console, Carla; Puri, Daniele

2018-01-01

Fosetyl-aluminum is a synthetic fungicide administered to plants especially to prevent diseases caused by the members of the Peronosporales and several Phytophthora species. Herein, we present a selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to analyze residues of fosetyl-A1 in air particulate matter. This study was performed in perspective of an exposure assessment of this substance of health concern in environments where high levels of fosetly-Al, relatively to airborne particulate matter, can be found after spraying it. The cleanup procedure of the analyte, from sampled filters of atmospheric particulate matter, was optimized using a Strata X solid-phase extraction cartridge, after accelerated extraction by using water. The chromatographic separation was achieved using a polymeric column based on hydrophilic interaction in step elution with water/acetonitrile, whereas the mass spectrometric detection was performed in negative electrospray ionization. The proposed method resulted to be a simple, fast, and suitable method for confirmation purposes. PMID:29686933

Electromembrane Surrounded Solid Phase Microextraction Followed by Injection Port Derivatization and Gas Chromatography-Flame Ionization Detector Analysis for Determination of Acidic Herbicides in Plant Tissue.

PubMed

Rezazadeh, Maryam; Yamini, Yadollah; Seidi, Shahram; Tahmasebi, Elham; Rezaei, Fatemeh

2014-04-09

Electromembrane surrounded solid phase microextraction (EM-SPME) of acidic herbicides was studied for the first time. In order to investigate the capability of this new microextraction technique to analyze acidic targets, chlorophenoxy acid (CPA) herbicides were quantified in plant tissue. 1-Octanol, was sustained in the pores of the wall of a hollow fiber and served as supported liquid membrane (SLM). Other EM-SPME related parameters, including extraction time, applied voltage, and pHs of the sample solution and the acceptor phase, were optimized using experimental design. A 20 min time frame was needed to reach the highest extraction efficiency of the analytes from a 24 mL alkaline sample solution across the organic liquid membrane and into the aqueous acceptor phase through a 50 V electrical field, and to their final adsorption on a carbonaceous anode. In addition to high sample cleanup, which made the proposed method appropriate for analysis of acidic compounds in a complicated media (plant tissue), 4.8% of 2-methyl-4-chlorophenoxyacetic acid (MCPA) and 0.6% of 2,4-dichlorophenoxyacetic acid (2,4-D) were adsorbed on the anode, resulting in suitable detection limits (less than 5 ng mL -1 ), and admissible repeatability and reproducibility (intra- and interassay precision were in the ranges of 5.2-8.5% and 8.8-12.0%, respectively). Linearity of the method was scrutinized within the ranges of 1.0-500.0 and 10.0-500.0 ng mL -1 for MCPA and 2,4-D, respectively, and coefficients of determination greater than 0.9958 were obtained. Optimal conditions of EM-SPME of the herbicides were employed for analysis of CPAs in whole wheat tissue.

Ultrasound-assisted leaching-dispersive solid-phase extraction followed by liquid-liquid microextraction for the determination of polybrominated diphenyl ethers in sediment samples by gas chromatography-tandem mass spectrometry.

PubMed

Fontana, Ariel R; Lana, Nerina B; Martinez, Luis D; Altamirano, Jorgelina C

2010-06-30

Ultrasound-assisted leaching-dispersive solid-phase extraction followed by dispersive liquid-liquid microextraction (USAL-DSPE-DLLME) technique has been developed as a new analytical approach for extracting, cleaning up and preconcentrating polybrominated diphenyl ethers (PBDEs) from sediment samples prior gas chromatography-tandem mass spectrometry (GC-MS/MS) analysis. In the first place, PBDEs were leached from sediment samples by using acetone. This extract was cleaned-up by DSPE using activated silica gel as sorbent material. After clean-up, PBDEs were preconcentrated by using DLLME technique. Thus, 1 mL acetone extract (disperser solvent) and 60 microL carbon tetrachloride (extraction solvent) were added to 5 mL ultrapure water and a DLLME technique was applied. Several variables that govern the proposed technique were studied and optimized. Under optimum conditions, the method detection limits (MDLs) of PBDEs calculated as three times the signal-to-noise ratio (S/N) were within the range 0.02-0.06 ng g(-1). The relative standard deviations (RSDs) for five replicates were <9.8%. The calibration graphs were linear within the concentration range of 0.07-1000 ng g(-1) for BDE-47, 0.09-1000 ng g(-1) for BDE-100, 0.10-1000 ng g(-1) for BDE-99 and 0.19-1000 ng g(-1) for BDE-153 and the coefficients of estimation were > or =0.9991. Validation of the methodology was carried out by standard addition method at two concentration levels (0.25 and 1 ng g(-1)) and by comparing with a reference Soxhlet technique. Recovery values were > or =80%, which showed a satisfactory robustness of the analytical methodology for determination of low PBDEs concentration in sediment samples. Copyright 2010 Elsevier B.V. All rights reserved.

Development of an ultra-high-pressure liquid chromatography-tandem mass spectrometry multi-residue sulfonamide method and its application to water, manure slurry, and soils from swine rearing facilities.

PubMed

Shelver, Weilin L; Hakk, Heldur; Larsen, Gerald L; DeSutter, Thomas M; Casey, Francis X M

2010-02-19

An analytical method was developed using ultra-high-pressure liquid chromatography-triple quadrupole-tandem mass spectrometry (UHPLC-TQ-MS/MS) to simultaneously analyze 14 sulfonamides (SA) in 6 min. Despite the rapidity of the assay the system was properly re-equilibrated in this time. No carryover was observed even after high analyte concentrations. The instrumental detection limit based on signal-to-noise ratio (S/N)>3, was below 1 pg/microL (5 pg on column) for all SAs except sulfachloropyridazine. Surface water, ground water, soil, and slurry manure contained in storage ponds in and around swine [Sus scrofa domesticus] rearing facilities were analyzed. Sample cleanup for ground water and surface water included using solid phase extraction (SPE) using Oasis hydrophilic-lipophilic balance (HLB) cartridges. The soil and slurry manure required tandem strong anion exchange (SAX) and HLB solid phase extraction cartridges for sample cleanup. With few exceptions, the recoveries ranged from 60 to 100% for all matrices. The minimum detectable levels were below 2.0 ng/L for water, 30 ng/L for slurry manure, and 45 ng/kg for soil except for sulfachloropyridazine. The coefficient of variation (CV) was within 20% for most of the compounds analyzed. Using this method, sulfamethazine concentrations of 2250-5060 ng/L, sulfamethoxazole concentrations of 108-1.47 x 10(6)ng/L, and sulfathiazole concentrations of 785-1700 ng/L were found in the slurry manure. Sulfadimethoxine (2.0-32 ng/L), sulfamethazine (2.0-5.1 ng/L), and sulfamethoxazole (20.5-43.0 ng/L) were found in surface water and ground water. In top soil (0-15 cm), sulfamethazine ranged 34.5-663 ng/kg dry weight in those locations that received slurry manure as a nutrient; no SAs were found in the soil depths between 46 and 61 cm. The speed makes the method practical for medium to high throughput applications. The sensitivity and positive analyte identification make the method suitable for the demanding requirements for real world applications. Published by Elsevier B.V.

Preparation of [13C3]-melamine and [13C3]-cyanuric acid and their application to the analysis of melamine and cyanuric acid in meat and pet food using liquid chromatography-tandem mass spectrometry.

PubMed

Varelis, P; Jeskelis, R

2008-10-01

For the determination of melamine and cyanuric acid the labelled internal standards [(13)C(3)]-melamine and [(13)C(3)]-cyanuric acid were synthesized using the common substrate [(13)C(3)]-cyanuric chloride by reaction with ammonia and acidified water, respectively. Standards with excellent isotopic and chemical purities were obtained in acceptable yields. These compounds were used to develop an isotope dilution liquid chromatography/mass spectrometry (LC/MS) method to determine melamine and cyanuric acid in catfish, pork, chicken, and pet food. The method involved extraction into aqueous methanol, liquid-liquid extraction and ion exchange solid phase clean-up, with normal phase high-performance liquid chromatography (HPLC) in the so-called hydrophilic interaction mode. The method had a limit of detection (LOD) of 10 microg kg(-1) for both melamine and cyanuric acid in the four foods with a percentage coefficient of variation (CV) of less than 10%. The recovery of the method at this level was in the range of 87-110% and 96-110% for melamine and cyanuric acid, respectively.

Determination of tafenoquine in dried blood spots and plasma using LC and fluorescence detection.

PubMed

Römsing, Susanne; Lindegardh, Niklas; Bergqvist, Yngve

2011-08-01

The growing problem of parasites developing resistance to the traditional antimalarial drugs makes the development of new effective and safe drugs crucial. Tafenoquine is a new promising antimalarial drug for prophylaxis and treatment. A bioanalytical method for the determination of tafenoquine in 100 µl of capillary blood applied onto sampling paper and in 100 µl of plasma has been developed and validated. The Whatman 31 ET Chr paper was treated with 0.6 mol/l tartaric acid to improve the extraction recovery and solid-phase extraction was used for cleanup procedure of the blood samples. Plasma samples were precipitated with methanol. Tafenoquine and internal standard were separated on a Zorbax SB-CN column by reversed-phase LC and detected with fluorescence detection at 262 and 470 nm. The within- and between-day variations were below 10 and 14%, respectively, over the range 50-200 nmol/l for capillary blood on sampling paper and below 6 and 10% for plasma samples. The LLOQ of the method was 50 nmol/l. The developed method has adequate sensitivity and is highly suitable for clinical studies in dried blood spots and plasma.

Improved sample preparation to determine acrylamide in difficult matrixes such as chocolate powder, cocoa, and coffee by liquid chromatography tandem mass spectroscopy.

PubMed

Delatour, Thierry; Périsset, Adrienne; Goldmann, Till; Riediker, Sonja; Stadler, Richard H

2004-07-28

An improved sample preparation (extraction and cleanup) is presented that enables the quantification of low levels of acrylamide in difficult matrixes, including soluble chocolate powder, cocoa, coffee, and coffee surrogate. Final analysis is done by isotope-dilution liquid chromatography-electrospray ionization tandem mass spectrometry (LC-MS/MS) using d3-acrylamide as internal standard. Sample pretreatment essentially encompasses (a) protein precipitation with Carrez I and II solutions, (b) extraction of the analyte into ethyl acetate, and (c) solid-phase extraction on a Multimode cartridge. The stability of acrylamide in final extracts and in certain commercial foods and beverages is also reported. This approach provided good performance in terms of linearity, accuracy and precision. Full validation was conducted in soluble chocolate powder, achieving a decision limit (CCalpha) and detection capability (CCbeta) of 9.2 and 12.5 microg/kg, respectively. The method was extended to the analysis of acrylamide in various foodstuffs such as mashed potatoes, crisp bread, and butter biscuit and cookies. Furthermore, the accuracy of the method is demonstrated by the results obtained in three inter-laboratory proficiency tests. Copyright 2004 American Chemical Society

High-performance liquid chromatography (HPLC) as a tool for monitoring the fate of fluazinam in soil.

PubMed

Hakala, Kati P; Tuomainen, Päivi M; Yli-Halla, Markku J; Hartikainen, Helinä

2014-01-01

Fluazinam is a widely used pesticide employed against the fungal disease late blight in potato cultivation. A specific, repeatable, and rapid high-performance liquid chromatography (HPLC) method utilizing a diode array detector (DAD) was developed to determine the presence of fluazinam in soil. The method consists of acetonitrile (ACN) extraction, clean-up with solid-phase extraction (SPE), and separation using a mobile phase consisting of 70% ACN and 30% water (v/v), including 0.02% acetic acid. HPLC was performed with a C18 column and the detection wavelength was 240 nm. The method was successfully applied to an incubation experiment and to soil samples taken from potato fields where fluazinam had been applied two to three times during the on-going growing season. In the 90-day incubation experiment, analytical standard fluazinam and the commercial fungicide Shirlan(®) were added to soil samples that had never been treated with fluazinam, and were then extracted with ACN and 0.01 M calcium chloride (CaCl2). Fluazinam was not extractable with CaCl2, indicating that it does not leach to watercourses in the dissolved form. Recovery with ACN extraction for sandy soils was 72-95% immediately after application and 53-73% after 90 days of incubation. Out of the eight potato field soil samples, fluazinam was found in two samples at concentrations of 2.1 mg kg(-1) and 1.9 mg kg(-1), well above the limit of quantification (0.1 mg kg(-1)).

Ion chromatographic methods for the detection of starch hydrolysis products in ruminal digesta.

PubMed

Barsuhn, K; Kotarski, S F

1991-06-21

Dionex high-performance ion chromatographic methods were evaluated for separation and quantitation of plant sugars and starch digestion products in the ruminal digesta of cattle. Mono- and disaccharides were eluted from a Dionex CarboPac PA1 column with sodium hydroxide used isocratically or as a pH gradient. Maltooligosaccharides which had a degree of polymerization (DP) less than 30 glucose residues were eluted in 60 min by a sodium hydroxide eluent containing a sodium acetate gradient. Carbohydrates were detected amperometrically. Responses were linear (r2 greater than 0.99) for glucose, disaccharides and maltooligosaccharides (DP less than 8). Precipitation and solid-phase extraction methods were evaluated for clean-up of samples of feedstuffs, ruminal contents, and bacterial culture fluids. Perchloric acid precipitation hydrolyzed sucrose but did not affect recoveries of cellobiose, isomaltose or maltose. Ethanol in concentrations of 79 and 86% precipitated maltooligosaccharides having chain lengths larger than 14 and 9 glucose residues, respectively. Maltooligosaccharide recoveries from solid-phase extraction columns varied with maltooligosaccharide size and column packing. Recoveries were greater than 94% for short chains (DP less than 6) eluted from phenyl-substituted columns and variable for all oligosaccharides eluted from C18 columns. Applications of these methods are presented and include: (1) detection of sugars in ruminant feed, (2) monitoring changes in ruminal sugars after feeding and (3) monitoring changes in extracellular sugars and oligosaccharides in the culture fluids of the ruminal bacterium, Bacteroides ruminicola.

Application of 1-(2-pyridylazo)-2-naphthol-modified nanoporous silica as a technique in simultaneous trace monitoring and removal of toxic heavy metals in food and water samples.

PubMed

Abolhasani, Jafar; Behbahani, Mohammad

2015-01-01

Solid-phase extraction is one the most useful and efficient techniques for sample preparation, purification, cleanup, preconcentration, and determination of heavy metals at trace levels. In this paper, functionalized MCM-48 nanoporous silica with 1-(2-pyridylazo)-2-naphthol was applied for trace determination of copper, lead, cadmium, and nickel in water and seafood samples. The experimental conditions such as pH, sample and eluent flow rate, type, concentration and volume of the eluent, breakthrough volume, and effect of coexisting ions were optimized for efficient solid-phase extraction of trace heavy metals in different water and seafood samples. The content of solutions containing the mentioned heavy metals was determined by flame atomic absorption spectrometry (FAAS), and the limits of detection were 0.3, 0.4, 0.6, and 0.9 ng mL(-1) for cadmium, copper, nickel, and lead, respectively. Recoveries and precisions were >98.0 and <4%, respectively. The adsorption capacity of the modified nanoporous silica was 178 mg g(-1) for cadmium, 110 mg g(-1) for copper, 98 mg g(-1) for nickel, and 210 mg g(-1) for lead, respectively. The functionalized MCM-48 nanoporous silica with 1-(2-pyridylazo)-2-naphthol was characterized by thermogravimetry analysis (TGA), differential thermal analysis (DTA), transmission electron microscopy (TEM), Fourier transform infrared spectrometry (FT-IR), X-ray diffraction (XRD), elemental analysis (CHN), and N2 adsorption surface area measurement.

Low-cost humic acid-bonded silica as an effective solid-phase extraction sorbent for convenient determination of aflatoxins in edible oils.

PubMed

Zhou, Neng-Zhi; Liu, Ping; Su, Xiao-Chuan; Liao, Yan-Hua; Lei, Ning-Sheng; Liang, Yong-Hong; Zhou, Shao-Huan; Lin, Wen-Si; Chen, Jie; Feng, Yu-Qi; Tang, Yang

2017-06-01

Aflatoxins (AFs) are highly toxic, mutagenic, carcinogenic, and teratogenic secondary metabolites produced by the toxigenic fungi Aspergillus flavus and Aspergillus parasiticus. AFs tend to contaminate a wide range of foods which is a serious and recurring food safety problem worldwide. Currently, immunoaffinity chromatography (IAC) has become the most conventional sample clean-up method for determining AFs in foodstuffs. However, IAC method is limited in the large-scale food analysis because it requires the use of expensive disposable cartridges and the IA procedure is time-consuming. Herein, to achieve the cost-effective determination of AFs in edible oils, we developed a promising solid-phase extraction (SPE) method based on commercially available humic acid-bonded silica (HAS) sorbent, followed by high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) analysis. In HAS-SPE, AFs can be captured by the HAS sorbent with both hydrophobic and hydrophilic interactions, whereas the oil matrix was captured only with the hydrophobic interactions. The oil matrix can be sufficiently washed off with isopropanol, while the AFs were still retained on the SPE packing, thus achieving selective extraction of AFs and clean-up of oil matrices. Under the optimal conditions of HAS-SPE, satisfactory recoveries ranging from 82% to 106% for four AFs (B 1 , B 2 , G 1 , and G 2 ) were achieved in various oil matrices, containing blended oil, tea oil, rapeseed oil, peanut oil, sunflower seed oil, corn oil, blended olive oil, rice oil, soybean oil, and sesame oil. Only minor matrix effects ranging from 99% to 105% for four AFs were observed. Moreover, the LODs of AFs between 0.012 and 0.035 μg/kg completely meet the regulatory levels fixed by the EU, China or other countries. The methodology was further validated for assaying the naturally contaminated peanut oils, and consistent results between the HAS-SPE and the referenced IAC were obtained. In addition, HAS-SPE can directly treat diluted oil sample without liquid-liquid extraction and is automatable, thus making it simple and convenient for the large-scale determination of AFs in edible oils. Using this method, we successfully detected four AFs in the naturally contaminated peanut oils, which is, to the best of our knowledge, the first report about the determination of AFs in edible oils using HA-based SPE. Copyright © 2017 Elsevier B.V. All rights reserved.

A review on solid phase extraction of actinides and lanthanides with amide based extractants.

PubMed

Ansari, Seraj A; Mohapatra, Prasanta K

2017-05-26

Solid phase extraction is gaining attention from separation scientists due to its high chromatographic utility. Though both grafted and impregnated forms of solid phase extraction resins are popular, the later is easy to make by impregnating a given organic extractant on to an inert solid support. Solid phase extraction on an impregnated support, also known as extraction chromatography, combines the advantages of liquid-liquid extraction and the ion exchange chromatography methods. On the flip side, the impregnated extraction chromatographic resins are less stable against leaching out of the organic extractant from the pores of the support material. Grafted resins, on the other hand, have a higher stability, which allows their prolong use. The goal of this article is a brief literature review on reported actinide and lanthanide separation methods based on solid phase extractants of both the types, i.e., (i) ligand impregnation on the solid support or (ii) ligand functionalized polymers (chemically bonded resins). Though the literature survey reveals an enormous volume of studies on the extraction chromatographic separation of actinides and lanthanides using several extractants, the focus of the present article is limited to the work carried out with amide based ligands, viz. monoamides, diamides and diglycolamides. The emphasis will be on reported applied experimental results rather than on data pertaining fundamental metal complexation. Copyright © 2017 Elsevier B.V. All rights reserved.

Determination of acrylamide in coffee and coffee products by GC-MS using an improved SPE clean-up.

PubMed

Soares, C; Cunha, S; Fernandes, J

2006-12-01

An improved gas chromatography-mass spectrometry (GC-MS) method to determine acrylamide (AA) in coffee and coffee products was developed. The method was based on two main purification steps: the first with ethanol and Carrez solutions in order to precipitate polysaccharides and proteins, respectively; and the second with a layered solid-phase extraction (SPE) column which proved to be efficient in the elimination of the main chromatographic interferences. The method is applicable to a wide range of coffee products. Twenty-six samples of different coffee products were analysed. The levels of AA were in the range 11.4-36.2 microg l-1 for 'espresso coffee' and 200.8-229.4 microg l-1 for coffee blends with cereals. The results indicate that the presence of cereals significantly increased the levels of AA.

Method for the Determination of Aconitum Alkaloids in Dietary Supplements and Raw Materials by Reversed-Phase Liquid Chromatography with Ultraviolet Detection and Confirmation by Tandem Mass Spectrometry: Single-Laboratory Validation

PubMed Central

Tang, Wai-Tong; Wong, Sui-Kay; Law, Tin-Yau; Pang, Kwok-Chu; Sin, Della; Tam, Yin-King

2008-01-01

A study of single-laboratory validation (SLV) of a reversed-phase liquid Chromatography (RP-LC) method was conducted for the determination of diester-diterpene Aconitum alkaloids, viz., aconitine, mesaconitine, and hypaconitine, in a variety of dietary supplements, including single-arid multiple-ingredient dry powder extracts, pills, capsules, and raw materials. The Aconitum alkaloids in the samples were extracted by diethyl ether in the presence of ammonia. After cleanup with solid-phase extraction to remove the matrix interferences, the alkaloids were determined by RP-LC with UV detection at 235 nm, and the results were confirmed by tandem mass Spectrometry. The linear responses for aconitine, mesaconitine, and hypaconitine based on the present LC system ranged from 0.5 to 200 μg/mL. Relative standard deviations of 2.0 to 6.9% were obtained from duplicate analysis of 6 test materials of different matrixes for the 3 Aconitum alkaloids performed by 2 analysts on 5 different days. The recoveries determined for supplements and raw materials spiked with 3 Aconitum alkaloids at levels of 2.5–10 μg/g were in the range of 86–99%. In view of the attainment of satisfactory results for accuracy, precision, and recovery in the SLV study, it is recommended that the method validation process proceed to a collaborative study. PMID:17225594

Evaluation of two fast and easy methods for pesticide residue analysis in fatty food matrixes.

PubMed

Lehotay, Steven J; Mastovská, Katerina; Yun, Seon Jong

2005-01-01

Two rapid methods of sample preparation and analysis of fatty foods (e.g., milk, eggs, and avocado) were evaluated and compared for 32 pesticide residues representing a wide range of physicochemical properties. One method, dubbed the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method for pesticide residue analysis, entailed extraction of 15 g sample with 15 mL acetonitrile (MeCN) containing 1% acetic acid followed by addition of 6 g anhydrous magnesium sulfate and 1.5 g sodium acetate. After centrifugation, 1 mL of the buffered MeCN extract underwent a cleanup step (in a technique known as dispersive solid-phase extraction) using 50 mg each of C18 and primary secondary amine sorbents plus 150 mg MgSO4. The second method incorporated a form of matrix solid-phase dispersion (MSPD), in which 0.5 g sample plus 2 g C18 and 2 g anhydrous sodium sulfate was mixed in a mortar and pestle and added above a 2 g Florisil column on a vacuum manifold. Then, 5 x 2 mL MeCN was used to elute the pesticide analytes from the sample into a collection tube, and the extract was concentrated to 0.5 mL by evaporation. Extracts in both methods were analyzed concurrently by gas chromatography/mass spectrometry and liquid chromatography/tandem mass spectrometry. The recoveries of semi-polar and polar pesticides were typically 100% in both methods (except that basic pesticides, such as thiabendazole and imazalil, were not recovered in the MSPD method), but recovery of nonpolar pesticides decreased as fat content of the sample increased. This trend was more pronounced in the QuEChERS method, in which case the most lipophilic analyte tested, hexachlorobenzene, gave 27 +/- 1% recovery (n=6) in avocado (15% fat) with a<10 ng/g limit of quantitation.

Determination of low levels of perchlorate in lettuce and spinach using ion chromatography-electrospray ionization mass spectrometry (IC-ESI-MS).

PubMed

Seyfferth, Angelia L; Parker, David R

2006-03-22

A sample preparation method was developed to quantify environmentally relevant (low micrograms per liter) concentrations of perchlorate (ClO4(-)) in leafy vegetables using IC-ESI-MS. Lettuce and spinach were macerated, centrifuged, and filtered, and the aqueous extracts were rendered water-clear using a one-step solid-phase extraction method. Total time for extraction and sample preparation was 6 h. Ion suppression was demonstrated and was likely due to unknown organics still present in the extract solution after cleanup. However, this interference was readily eliminated using a Cl(18)O4(-) internal standard at 1 microg/L in all standards and samples. Hydroponically grown perchlorate-free butterhead lettuce was spiked to either 10.3 or 37.7 microg/kg of fresh weight (FW), and recoveries were between 91 and 98% and between 93 and 101%, respectively. Five types of lettuce and spinach from a local grocery store were then analyzed; they contained from 0.6 to 6.4 microg/kg of FW. Spike recoveries using the store-bought samples ranged from 89 to 100%. The method detection limit for perchlorate in plant extracts is 40 ng/L, and the corresponding minimum reporting limit is 200 ng/L or 0.8 microg/kg of FW.

Assessment of priority pesticides, degradation products, and pesticide adjuvants in groundwaters and top soils from agricultural areas of the Ebro river basin.

PubMed

Hildebrandt, Alain; Lacorte, Sílvia; Barceló, Damià

2007-02-01

Gas chromatography-mass spectrometry (GC/MS) was employed for the determination of 30 widely used pesticides including various transformation products and alkylphenols in water and agricultural soils with the aim of assessing the impact of these compounds in agricultural soils and the underlying aquifer. The extraction, clean-up, and analytical procedures were optimized for both water and soil samples to provide a highly robust method capable of determining target analytes at the ppb-ppt level with high precision. For water samples, different solid-phase extraction cartridges and conditions were optimized; similarly, pressurized liquid extraction conditions were tested to provide interference-free extracts and high sensitivity. Instrumental LODs of 3-4 pg were obtained. The multi-residue extraction procedures were applied to the analysis of groundwaters and agricultural soils from the Ebro river basin (NE Spain). Most ubiquitous herbicides detected were triazines but some acetanilides and organophosphorus pesticides were also found; the pesticide additive tributylphosphate was found in all water samples. Levels varied between 0.57 and 5.37 microg/L in groundwater, whereas nonylphenol was the sole compound detected in soil. Alkylphenols are used as adjuvants in pesticide formulations and are present in sludges employed as soil fertilizers. Occurrence was found to be similar to other environmental studies.

Combination of magnetic dispersive micro solid-phase extraction and supramolecular solvent-based microextraction followed by high-performance liquid chromatography for determination of trace amounts of cholesterol-lowering drugs in complicated matrices.

PubMed

Arghavani-Beydokhti, Somayeh; Rajabi, Maryam; Asghari, Alireza

2017-07-01

A novel, efficient, rapid, simple, sensitive, selective, and environmentally friendly method termed magnetic dispersive micro solid-phase extraction combined with supramolecular solvent-based microextraction (Mdμ-SPE-SSME) followed by high-performance liquid chromatography (HPLC) with UV detection is introduced for the simultaneous microextraction of cholesterol-lowering drugs in complicated matrices. In the first microextraction procedure, using layered double hydroxide (LDH)-coated Fe 3 O 4 magnetic nanoparticles, an efficient sample cleanup is simply and rapidly provided without the need for time-consuming centrifugation and elution steps. In the first step, desorption of the target analytes is easily performed through dissolution of the LDH-coated magnetic nanoparticles containing the target analytes in an acidic solution. In the next step, an emulsification microextraction method based on a supramolecular solvent is used for excellent preconcentration, ultimately resulting in an appropriate determination of the target analytes in real samples. Under the optimal experimental conditions, the Mdμ-SPE-SSME-HPLC-UV detection procedure provides good linearity in the ranges of 1.0-1500 ng mL -1 , 1.5-2000 ng mL -1 , and 2.0-2000 ng mL -1 with coefficients of determination of 0.995 or less, low limits of detection (0.3, 0.5, and 0.5 ng mL -1 ), and good extraction repeatabilities (relative standard deviations below 7.8%, n = 5) in deionized water for rosuvastatin, atorvastatin, and gemfibrozil, respectively. Finally, the proposed method is successfully applied for the determination of the target analytes in complicated matrices. Graphical Abstract Mdμ-SPE-SSME procedure.

Molecularly imprinted polymer solid-phase extraction coupled to square wave voltammetry at carbon fibre microelectrodes for the determination of fenbendazole in beef liver.

PubMed

Guzmán-Vázquez de Prada, A; Loaiza, Oscar A; Serra, B; Morales, D; Martínez-Ruiz, P; Reviejo, A J; Pingarrón, J M

2007-05-01

A molecularly imprinted polymer was developed and used for solid-phase extraction (MISPE) of the antihelmintic fenbendazole in beef liver samples. Detection of the analyte was accomplished using square wave voltammetry (SWV) at a cylindrical carbon fibre microelectrode (CFME). A mixture of MeOH/HAc (9:1) was employed both as eluent in the MISPE system and as working medium for electrochemical detection of fenbendazole. The limit of detection was 1.9x10(-7) mol L-1 (57 microg L-1), which was appropriate for the determination of fenbendazole at the maximum residue level permitted by the European Commission (500 microg kg-1 in liver). Given that the SW voltammetric analysis could not be directly performed in the sample extract as a consequence of interference from some sample components, a sample clean-up with a MIP for selectively retaining fenbendazole was performed. The MIP was synthesized using a 1:8:22 template/methacrylic acid/ethylene glycol dimethacrylate ratio. A Britton-Robinson Buffer of pH 9.0 was selected for retaining fenbendazole in the MIP cartridges, and an eluent volume of 5.0 mL at a flow rate of 2.0 mL min-1 was chosen in the elution step. Cross-reactivity with the MIP was observed for other benzimidazoles. The synthesized MIP exhibited a good selectivity for benzimidazoles with respect to other veterinary drugs. The applicability of the MISPE-SWV method was tested with beef liver samples, spiked with fenbendazole at 5,000 and 500 microg kg-1. Results obtained for ten different liver samples yielded mean recoveries of (95+/-12)% and (96+/-11)% for the upper and lower concentration level, respectively.

Isolation and determination of ivermectin in post-mortem and in vivo tissues of dung beetles using a continuous solid phase extraction method followed by LC-ESI+-MS/MS

PubMed Central

Ortiz, Antonio J.; Cortez, Vieyle; Azzouz, Abdelmonaim

2017-01-01

A new analytical method based on solvent extraction, followed by continuous solid-phase extraction (SPE) clean-up using a polymeric sorbent, was demonstrated to be applicable for the detection of ivermectin in complex biological matrices of dung beetles (hemolymph, excreta or dry tissues) using liquid chromatography combined with positive electrospray ionization tandem mass spectrometry (LC/ESI+–MS/MS). Using a signal-to-noise ratio of 3:1, the limit of detection (LOD) in the insect matrices at trace levels was 0.01 ng g–1 and the limit of quantification (LOQ) was 0.1 ng g–1. The proposed method was successfully used to quantitatively determine the levels of ivermectin in the analysis of small samples in in vivo and post mortem samples, demonstrating the usefulness for quantitative analyses that are focused on future pharmacokinetic and bioavailability studies in insects and the establishment of a new protocol to study the impact of ivermectin on non-target arthropods such as dung beetles and other insects that are related with the “dung community”. Because satisfactory precision and accuracy values were obtained in both in vivo matrices, we suggest that the method can be consistently used for quantitative determinations that are focused on future pharmacokinetic and bioavailability studies in insects. Furthermore, this new analytical method was successfully applied to biological samples of dead dung beetles from the field suggesting that the method can be used to establish a new routine analysis of ivermectin residues in insect carcasses that is applied to complement typical mortality tests. PMID:28207908

Multiresidue determination of chlorophenoxy acid herbicides in human urine samples by use of solid-phase extraction and capillary LC-UV detection.

PubMed

Rosales-Conrado, N; León-González, M E; Pérez-Arribas, L V; Polo-Díez, L M

2008-01-01

Chlorophenoxy acid herbicides are intensively applied to get rid of unwanted plants because of their low cost and selectivity. Due to their toxicity, which depends on their chemical form, the European Community has established legal directives to restrict their use and to control their maximum residue levels in several matrices. Determination of chlorophenoxy acids-2,4-dichlorophenoxyacetic acid (2,4-D), 4-chloro-2-methylphenoxyacetic acid (MCPA), 2-(2,4-dichlorophenoxy)propanoic acid (2,4-DP), 2-(4-chloro-2-methylphenoxy)propanoic acid (MCPP), 4-(4-chloro-2-methylphenoxy)butanoic acid (MCPB) and 2-(2,4,5-trichlorophenoxy)propanoic acid (2,4,5-TP) in spiked human urine samples has been carried out by capillary LC, after solid-phase extraction on a column packed with silica C18 restricted-access material. Chromatographic analysis was performed in gradient-elution mode at 25 degrees C, with injection of 20 microL low-organic-solvent composition herbicide solutions for focusing purposes on the head of the capillary column, and diode array detection at 232 nm. Urine samples collected during 24 h from healthy and unexposed volunteers were spiked in the concentration range 25-150 microg L(-1); recoveries obtained were between 66 and 100% (n = 6 for each spiked level) and RSDs (relative standard deviations) were between 1 and 5%. Detection limits in the urine samples from volunteers were between 3.5 and 6.0 microg L(-1). The developed methodology has allowed the clean-up and preconcentration of low volumes of untreated human urine without previous treatment, showing the effectiveness of the employed SPE sorbent for extracting the target analytes and ultimately resulting in the reduction of the sample-preparation time.

Biological treatment of soils contaminated with hydrophobic organics using slurry- and solid-phase techniques

NASA Astrophysics Data System (ADS)

Cassidy, Daniel H.; Irvine, Robert L.

1995-10-01

Both slurry-phase and solid-phase bioremediation are effective ex situ soil decontamination methods. Slurrying is energy intensive relative to solid-phase treatment, but provides homogenization and uniform nutrient distribution. Limited contaminant bioavailability at concentrations above the required cleanup level reduces biodegradation rates and renders solid phase bioremediation more cost effective than complete treatment in a bio-slurry reactor. Slurrying followed by solid-phase bioremediation combines the advantages and minimizes the weaknesses of each treatment method when used alone. A biological treatment system consisting of slurrying followed by aeration in solid phase bioreactors was developed and tested in the laboratory using a silty clay loam contaminated with diesel fuel. The first set of experiments was designed to determine the impact of the water content and mixing time during slurrying on the rate an extent of contaminant removal in continuously aerated solid phase bioreactors. The second set of experiments compared the volatile and total diesel fuel removal in solid phase bioreactors using periodic and continuous aeration strategies. Results showed that slurrying for 1.5 hours at a water content less than saturation markedly increased the rate and extent of contaminant biodegradation in the solid phase bioreactors compared with soil having no slurry pretreatment. Slurrying the soil at or above its saturation moisture content resulted in lengthy dewatering times which prohibited aeration, thereby delaying the onset of biological treatment in the solid phase bioreactors. Results also showed that properly operated periodic aeration can provide less volatile contaminant removal and a grater fraction of biological contaminant removal than continuous aeration.

Solid-phase glycan isolation for glycomics analysis

PubMed Central

Yang, Shuang; Zhang, Hui

2013-01-01

Glycosylation is one of the most significant protein PTMs. The biological activities of proteins are dramatically changed by the glycans associated with them. Thus, structural analysis of the glycans of glycoproteins in complex biological or clinical samples is critical in correlation with the functions of glycans with diseases. Profiling of glycans by HPLC-MS is a commonly used technique in analyzing glycan structures and quantifying their relative abundance in different biological systems. Methods relied on MS require isolation of glycans from negligible salts and other contaminant ions since salts and ions may interfere with the glycans, resulting in poor glycan ionization. To accomplish those objectives, glycan isolation and clean-up methods including SPE, liquid-phase extraction, chromatography, and electrophoresis have been developed. Traditionally, glycans are isolated from proteins or peptides using a combination of hydrophobic and hydrophilic columns: proteins and peptides remain on hydrophobic absorbent while glycans, salts, and other hydrophilic reagents are collected as flowthrough. The glycans in the flowthrough are then purified through graphite-activated carbon column by hydrophilic interaction LC. Yet, the drawback in these affinity-based approaches is nonspecific binding. As a result, chemical methods by hydrazide or oxime have been developed for solid-phase isolation of glycans with high specificity and yield. Combined with high-resolution MS, specific glycan isolation techniques provide tremendous potentials as useful tools for glycomics analysis. PMID:23090885

Solid-phase glycan isolation for glycomics analysis.

PubMed

Yang, Shuang; Zhang, Hui

2012-12-01

Glycosylation is one of the most significant protein PTMs. The biological activities of proteins are dramatically changed by the glycans associated with them. Thus, structural analysis of the glycans of glycoproteins in complex biological or clinical samples is critical in correlation with the functions of glycans with diseases. Profiling of glycans by HPLC-MS is a commonly used technique in analyzing glycan structures and quantifying their relative abundance in different biological systems. Methods relied on MS require isolation of glycans from negligible salts and other contaminant ions since salts and ions may interfere with the glycans, resulting in poor glycan ionization. To accomplish those objectives, glycan isolation and clean-up methods including SPE, liquid-phase extraction, chromatography, and electrophoresis have been developed. Traditionally, glycans are isolated from proteins or peptides using a combination of hydrophobic and hydrophilic columns: proteins and peptides remain on hydrophobic absorbent while glycans, salts, and other hydrophilic reagents are collected as flowthrough. The glycans in the flowthrough are then purified through graphite-activated carbon column by hydrophilic interaction LC. Yet, the drawback in these affinity-based approaches is nonspecific binding. As a result, chemical methods by hydrazide or oxime have been developed for solid-phase isolation of glycans with high specificity and yield. Combined with high-resolution MS, specific glycan isolation techniques provide tremendous potentials as useful tools for glycomics analysis. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Polyfluoroalkyl phosphate esters and perfluoroalkyl carboxylic acids in target food samples and packaging--method development and screening.

PubMed

Gebbink, Wouter A; Ullah, Shahid; Sandblom, Oskar; Berger, Urs

2013-11-01

Polyfluoroalkyl phosphate mono-, di-, and tri-esters (mono-, di-, and triPAPs) are used to water- and grease-proof food packaging materials, and these chemicals are known precursors to perfluoroalkyl carboxylic acids (PFCAs). Existing analytical methods for PAPs lack sample clean-up steps in the sample preparation. In the present study, a method based on ultra performance liquid chromatography coupled to tandem mass spectrometry (UPLC/MS/MS) was developed and optimized for the analysis of mono-, di-, and triPAPs, including a clean-up step for the raw extracts. The method was applied to food samples and their PAP-containing packaging materials. The optimized UPLC/MS/MS method enabled the separation and identification of a total of 4 monoPAPs, 16 diPAPs, and 7 triPAPs in the technical mixture Zonyl®-RP. For sample clean-up, weak anion exchange solid phase extraction columns were tested. PAPs standard solutions spiked onto the columns were separated into a fraction containing neutral compounds (triPAPs) and a fraction with ionic compounds (mono- and diPAPs) with recoveries between 72-110%. Method limits of quantification for food samples were in the sub to low picogram per gram range. For quantitative analysis of PAPs, compound-specific labeled internal standards showed to be essential as sorption and matrix effects were observed. Mono-, di-, and/or triPAPs were detected in all food packaging materials obtained from the Swedish market. Up to nine diPAPs were detected in the food samples, with the 6:2/6:2 and 6:2/8:2 diPAPs as the dominant compounds. DiPAP concentrations in the food samples ranged from 0.9 to 36 pg/g, which was comparable to individual PFCA concentrations in the same samples. Consumption of food packed in PAP-containing materials could be an indirect source of human exposure to PFCAs.

Matrix solid phase dispersion assisted enzymatic hydrolysis as a novel approach for cocaine and opiates isolation from human hair.

PubMed

Míguez-Framil, Martha; Cabarcos, Pamela; Tabernero, María Jesús; Bermejo, Ana María; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Antonio

2013-11-05

The possibility of assisting enzymatic hydrolysis (EH) procedures by sample disruption mechanisms inherent to matrix solid phase dispersion (MSPD) has been explored in the current study. EH of hair specimens from poly-drug abusers was assisted by dispersing/blending the sample (0.05 g) with alumina (2.25 g) before loading the dissolved enzyme (6 mL of 1 mg mL(-1) Pronase E in 1.4 M/1.4 M Tris/HCl, pH 7.3) through the hair-alumina solid phase packaged inside a disposable MSPD syringe. The MSPD-EH method was developed, and it proved to offer quantitative results when isolating cocaine, benzoylecgonine (BZE), codeine, morphine and 6-monoacethylmorphine (6-MAM) from human hair samples. The procedure allows an on column clean-up/pre-concentration procedure of the isolated targets by attaching a previously conditioned Oasis HLB cartridge to the end of the MSPD syringe. The EH procedure of human hair with Pronase E can therefore be shortened to approximately 30 min. Within this time, sample blending/dispersion, MSPD syringe package, elution (EH when dissolved Pronase E is passing through the sample-dispersant bed), and extract clean-up and target pre-concentration stages are achieved. Gas chromatography-mass spectrometry (GC-MS) was used for determining each target after elution from the Oasis HLB cartridges with 2 mL of 2% (v/v) acetic acid in methanol, concentration by N2 stream evaporation, and dried extract derivatization with N-methyl-tert-butylsilyltrifluoroacetamide (BSTFA) and chlorotrimethylsilane (TMCS). The method was validated according to the guidance for bioanalytical method validation of the US Department of Health and Human Services, Food and Drug Administration. The simplicity of the proposed approach makes it a useful procedure for screening/quantifying drugs of abuse in hair specimens from poly-drug abusers. Copyright © 2013 Elsevier B.V. All rights reserved.

Cleanup procedure for water, soil, animal and plant extracts for the use of electron-capture detector in the gas chromatographic analysis of organophosphorus insecticide residues.

PubMed

Kadoum, A M

1968-07-01

A simple, aqueous acetonitrile partition cleanup method for analyses of some common organophosphorus insecticide residues is described. The procedure described is for cleanup and quantitative recovery of parathion, methyl parathion, diazinon, malathion and thimet from different extracts. Those insecticides in the purified extracts of ground water, grain, soil, plant and animal tissues can be detected quantitatively by gas chromatography with an electron capture-detector at 0.01 ppm. Cleanup is satisfactory for paper and thin-layer chromatography for further identification of individual insecticides in the extracts.

Quantitative ionspray liquid chromatographic/tandem mass spectrometric determination of reserpine in equine plasma.

PubMed

Anderson, M A; Wachs, T; Henion, J D

1997-02-01

A method based on ionspray liquid chromatography/tandem mass spectrometry (LC/MS/MS) was developed for the determination of reserpine in equine plasma. A comparison was made of the isolation of reserpine from plasma by liquid-liquid extraction and by solid-phase extraction. A structural analog, rescinnamine, was used as the internal standard. The reconstituted extracts were analyzed by ionspray LC/MS/MS in the selected reaction monitoring (SRM) mode. The calibration graph for reserpine extracted from equine plasma obtained using liquid-liquid extraction was linear from 10 to 5000 pg ml-1 and that using solid-phase extraction from 100 to 5000 pg ml-1. The lower level of quantitation (LLQ) using liquid-liquid and solid-phase extraction was 50 and 200 pg ml-1, respectively. The lower level of detection for reserpine by LC/MS/MS was 10 pg ml-1. The intra-assay accuracy did not exceed 13% for liquid-liquid and 12% for solid-phase extraction. The recoveries for the LLQ were 68% for liquid-liquid and 58% for solid-phase extraction.

Development and validation of a multiresidue method for the analysis of polybrominated diphenyl ethers, new brominated and organophosphorus flame retardants in sediment, sludge and dust.

PubMed

Cristale, Joyce; Lacorte, Silvia

2013-08-30

This study presents a multiresidue method for simultaneous extraction, clean-up and analysis of priority and emerging flame retardants in sediment, sewage sludge and dust. Studied compounds included eight polybrominated diphenyl ethers congeners, nine new brominated flame retardants and ten organophosphorus flame retardants. The analytical method was based on ultrasound-assisted extraction with ethyl acetate/cyclohexane (5:2, v/v), clean-up with Florisil cartridges and analysis by gas chromatography coupled to tandem mass spectrometry (GC-EI-MS/MS). Method development and validation protocol included spiked samples, certified reference material (for dust), and participation in an interlaboratory calibration. The method proved to be efficient and robust for extraction and determination of three families of flame retardants families in the studied solid matrices. The method was applied to river sediment, sewage sludge and dust samples, and allowed detection of 24 among the 27 studied flame retardants. Organophosphate esters, BDE-209 and decabromodiphenyl ethane were the most ubiquitous contaminants detected. Copyright © 2013 Elsevier B.V. All rights reserved.

A new solid-phase extraction and HPLC method for determination of patulin in apple products and hawthorn juice in China.

PubMed

Zhou, Yuchun; Kong, Weijun; Li, Yan; Logrieco, Antonio F; Xu, Jun; Yang, Meihua

2012-03-01

A new solid-phase extraction (SPE) pretreatment method using a home-made polyvinylpolypyrrolidone-florisil (PVPP-F) column was developed for the analysis of patulin in apple and hawthorn products in China. Fifty samples (25 apple juices, 12 apple jams, and 13 hawthorn juices) were prepared using the new method and then analyzed by high performance liquid chromatography with diode array detection (HPLC-DAD) on an Agela Venusil MP C(18) reversed-phase column (4.6 mm × 250 mm, 5 μm). The cleanup results for all samples using home-made PVPP-F column were compared with those obtained using a MycoSep®228 AflaPat column. The correlation coefficient R (0.9998) fulfilled the requirement of linearity for patulin in the concentration range of 2.5-250 μg/kg. The limits of detection (LODs) and quantification (LOQs) of patulin were 3.99 and 9.64 μg/kg for PVPP-F column, and 3.56 and 8.07 μg/kg for MycoSep®228 AflaPat column, respectively. Samples were spiked with patulin at levels ranging from 25 to 250 μg/kg, and recoveries using PVPP-F and MycoSep®228 AflaPat columns were in the range of 81.9-100.9% and 86.4-103.9%, respectively. Naturally occurring patulin was found in 2 of 25 apple juice samples (8.0%) and 1 of 13 hawthorn juice samples (7.7%) at concentrations ranging from 12.26 to 36.81 μg/kg. The positive results were further confirmed by liquid chromatography electrospray ionization mass spectrometry (LC-ESI-MS). © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multiresidue analytical method using dispersive solid-phase extraction and gas chromatography/ion trap mass spectrometry to determine pharmaceuticals in whole blood.

PubMed

Plössl, Florian; Giera, Martin; Bracher, Franz

2006-11-24

A convenient analytical method for the simultaneous determination of more than 40 pharmaceuticals belonging to various therapeutic categories in whole blood has been developed. Exemplarily, the method was fully validated for eight different pharmaceuticals. The procedure entails addition of acetonitrile, magnesium sulfate and sodium chloride to a small amount of blood, then the mixture is shaken intensively and centrifuged for phase separation. An aliquot of the organic layer is cleaned up by dispersive solid-phase extraction employing bulk sorbents as well as magnesium sulfate for the removal of residual water. This method was based on the QuEChERS approach developed for pesticide residue analysis in food. Gas chromatography/ion trap mass spectrometry (GC/MS) with electron (EI) and chemical (CI) ionisation was then used for qualitative and quantitative determination of the pharmaceuticals. The dispersive SPE with PSA (sorbent functionalized with primary and secondary amines) was found more suitable than aminopropyl and a styrene-divinylbenzene sorbent for sample clean-up before drug level determination in whole blood and plasma, as it was found that most of endogenous matrix components were removed and the analytes were isolated from spiked samples with recoveries above 80%. Variation coefficients of the repeatability typically smaller than 10% have been achieved for a wide range of the investigated substances. The used analytical conditions allowed to separate successively a variety of drugs and poisons with the typical limit of detection at <20 ng mL(-1) levels using 1 microL injection of equivalent blood sample in whole blood. The method is simple, rapid, cheap and very effective for therapeutic drug monitoring and forensic chemistry.

Solid phase extraction with high polarity Carb/PSA as composite fillers prior to UPLC-MS/MS to determine six bisphenols and alkylphenols in trace level hotpot seasoning.

PubMed

Dong, Hao; Zeng, Xiaofang; Bai, Weidong

2018-08-30

The present study reports an ultra high-performance liquid chromatography tandem mass spectrometry method for the simultaneous determination of six bisphenols (bisphenol A, bisphenol B and bisphenol F) and alkylphenols (4-nonylphenol, 4-n-nonylphenol and octylphenol) in hotpot seasoning. Samples were dispersed in n-hexane after addition of internal standards bisphenol A-d 4 and 4-n-nonylphenol-d 4 . Sample solutions were then centrifuged, and the supernatants purified using solid phase extraction with high polarity Carb/PSA composite fillers. Six target analytes were separated on a Waters ACQUITY BEH C18 column by gradient elution with methanol and 0.05% ammonium hydroxide in water as the mobile phase, and determined under multiple reactions monitoring mode. The limits of detection and quantitation, matrix effect, recovery and precision of the method were investigated. Results were linear in the concentration range 0.1-250 µg/L for all compounds of interest, with R 2  > 0.9950. Limits of detection were in the range 0.1-0.4 μg/kg, and limits of quantitation were between 0.5 μg/kg and 1.0 μg/kg. The mean recoveries for negative samples at three spiked concentrations were in the range 87.9%-102.4%, and the intra-day precision and inter-day precision were in the ranges 2.1-8.2% and 4.8-11.2%, respectively. This method is accurate and sensitive, and had good clean-up characteristics, which might apply to screening and quantitation of target bisphenols and alkylphenols in hotpot seasoning. Copyright © 2018 Elsevier Ltd. All rights reserved.

Optimization and development of a high-performance liquid chromatography method for the simultaneous determination of vitamin E and carotenoids in tomato fruits.

PubMed

Irakli, Maria; Chatzopoulou, Paschalina; Kadoglidou, Kalliopi; Tsivelika, Nektaria

2016-09-01

A simple and reliable high-performance liquid chromatography method was developed and validated for the simultaneous determination of lipophilic antioxidants in tomato fruits using C30 column operated at 15°C and a gradient mobile phase based on acetonitrile/methanol/dichloromethane in a total run time of 30 min. Diode array and fluorescence detectors were used respectively for the detection of carotenoids (lutein, zeaxanthin, cryptoxanthin, lycopene, and β-carotene) and vitamin E analogs (α-, β-, γ-, and δ-tocopherols, and tocotrienols). The best extraction yield of analytes in tomato fruits was achieved by employing ethyl acetate/hexane (1:1, v/v) after several treatments with various solvents. In addition, low extraction yields were obtained for carotenoids compared to tocopherols by adopting solid-phase extraction as a second clean-up step. The method was validated on the basis of recovery, precision, linearity, and limit of detection and quantification using spiked tomato samples. The method was applied to cherry and medium-sized tomato fruits. Lycopene was found to be present in largest amount in tomato pulp, followed by β-carotene and lutein. Due to its simplicity, rapidity, and efficiency, the method is suitable for routine analysis of lipophilic antioxidants in tomato fruits, and may also be applied to other vegetables of similar phytochemical profiles. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-throughput biomonitoring of dioxins and polychlorinated biphenyls at the sub-picogram level in human serum.

PubMed

Focant, Jean-François; Eppe, Gauthier; Massart, Anne-Cécile; Scholl, Georges; Pirard, Catherine; De Pauw, Edwin

2006-10-13

We report on the use of a state-of-the-art method for the measurement of selected polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polychlorinated biphenyls in human serum specimens. The sample preparation procedure is based on manual small size solid-phase extraction (SPE) followed by automated clean-up and fractionation using multi-sorbent liquid chromatography columns. SPE cartridges and all clean-up columns are disposable. Samples are processed in batches of 20 units, including one blank control (BC) sample and one quality control (QC) sample. The analytical measurement is performed using gas chromatography coupled to isotope dilution high-resolution mass spectrometry. The sample throughput corresponds to one series of 20 samples per day, from sample reception to data quality cross-check and reporting, once the procedure has been started and series of samples keep being produced. Four analysts are required to ensure proper performances of the procedure. The entire procedure has been validated under International Organization for Standardization (ISO) 17025 criteria and further tested over more than 1500 unknown samples during various epidemiological studies. The method is further discussed in terms of reproducibility, efficiency and long-term stability regarding the 35 target analytes. Data related to quality control and limit of quantification (LOQ) calculations are also presented and discussed.

Preparation of a reversed-phase/anion-exchange mixed-mode spherical sorbent by Pickering emulsion polymerization for highly selective solid-phase extraction of acidic pharmaceuticals from wastewater.

PubMed

Huang, Chaonan; Li, Yun; Yang, Jiajia; Peng, Junyu; Jin, Jing; Dhanjai; Wang, Jincheng; Chen, Jiping

2017-10-27

The present work represents a simple and effective preparation of a novel mixed-mode anion-exchange (MAX) sorbent based on porous poly[2-(diethylamino)ethyl methacrylate-divinylbenzene] (poly(DEAEMA-DVB)) spherical particles synthesized by one-step Pickering emulsion polymerization. The poly(DEAEMA-DVB) particles were quaternized with 1,4-butanediol diglycidyl ether (BDDE) followed by triethylamine (TEA) via epoxy-amine reaction to offer strong anion exchange properties. The synthesized MAX sorbent was characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, nitrogen adsorption-desorption measurements and elemental analysis. The MAX sorbent possessed regular spherical shape and narrow diameter distribution (15-35μm), a high IEC of 0.54meq/g, with carbon and nitrogen contents of 80.3% and 1.62%, respectively. Compared to poly(DEAEMA-DVB), the MAX sorbent exhibited decreased S BET (390.5 vs. 515.3m 2 g -1 ), pore volume (0.74 vs. 0.85cm 3 g -1 ) and pore size (16.8 vs. 17.3nm). Moreover, changes of N content for producing the MAX sorbent reveal a successful two-step quaternization, which can be highly related to such a high IEC. Finally, the MAX sorbent was successfully evaluated for selective isolation and purification of some selected acidic pharmaceuticals (ketoprofen, KEP; naproxen, NAP; and ibuprofen, IBP) from neutral (hydrocortisone, HYC), basic (carbamazepine, CAZ; amitriptyline, AMT) pharmaceuticals and other interferences in water samples using solid phase extraction (SPE). An efficient analytical method based on the MAX-based mixed-mode SPE coupled with HPLC-UV was developed for highly selective extraction and cleanup of acidic KEP, NAP and IBP in spiked wastewater samples. The developed method exhibited good sensitivity (0.009-0.085μgL -1 limit of detection), satisfactory recoveries (82.1%-105.5%) and repeatabilities (relative standard deviation < 7.9%, n=3). Copyright © 2017 Elsevier B.V. All rights reserved.

Rapid determination of the volatile components in tobacco by ultrasound-microwave synergistic extraction coupled to headspace solid-phase microextraction with gas chromatography-mass spectrometry.

PubMed

Yang, Yanqin; Chu, Guohai; Zhou, Guojun; Jiang, Jian; Yuan, Kailong; Pan, Yuanjiang; Song, Zhiyu; Li, Zuguang; Xia, Qian; Lu, Xinbo; Xiao, Weiqiang

2016-03-01

An ultrasound-microwave synergistic extraction coupled to headspace solid-phase microextraction was first employed to determine the volatile components in tobacco samples. The method combined the advantages of ultrasound, microwave, and headspace solid-phase microextraction. The extraction, separation, and enrichment were performed in a single step, which could greatly simplify the operation and reduce the whole pretreatment time. In the developed method, several experimental parameters, such as fiber type, ultrasound power, and irradiation time, were optimized to improve sampling efficiency. Under the optimal conditions, there were 37, 36, 34, and 36 components identified in tobacco from Guizhou, Hunan, Yunnan, and Zimbabwe, respectively, including esters, heterocycles, alkanes, ketones, terpenoids, acids, phenols, and alcohols. The compound types were roughly the same while the contents were varied from different origins due to the disparity of their growing conditions, such as soil, water, and climate. In addition, the ultrasound-microwave synergistic extraction coupled to headspace solid-phase microextraction method was compared with the microwave-assisted extraction coupled to headspace solid-phase microextraction and headspace solid-phase microextraction methods. More types of volatile components were obtained by using the ultrasound-microwave synergistic extraction coupled to headspace solid-phase microextraction method, moreover, the contents were high. The results indicated that the ultrasound-microwave synergistic extraction coupled to headspace solid-phase microextraction technique was a simple, time-saving and highly efficient approach, which was especially suitable for analysis of the volatile components in tobacco. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous determination of atropine and scopolamine in buckwheat and related products using modified QuEChERS and liquid chromatography tandem mass spectrometry.

PubMed

Chen, Hongping; Marín-Sáez, Jesús; Romero-González, Roberto; Garrido Frenich, Antonia

2017-03-01

A method was developed for the determination of atropine and scopolamine in buckwheat and related products. A modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) extraction procedure was evaluated. Dispersive solid phase extraction (d-SPE) was studied as clean-up step, using graphitized black carbon (GBC) and primary secondary amine (PSA). The extract was diluted with water (50:50, v/v) prior to chromatographic analysis. The method was validated and recoveries (except chia samples spiked at 10μg/kg) ranged from 75% to 92%. Intra and inter-day precision was lower than or equal to 17%. The limit of quantification of atropine and scopolamine was 0.4 and 2μg/kg, respectively. Eight types of samples (buckwheat, wheat, soy, buckwheat flour, buckwheat noodle, amaranth grain, chia seeds and peeled millet) were analyzed. Target compounds were not found above the detection limits of the method, but three transformation products of scopolamine (norscopine, hydroscopolamine and dihydroxyscopolamine) were putative identified in the tested samples using high resolution mass spectrometry (Exactive-Orbitrap). Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparison of sample preparation methods combined with fast gas chromatography-mass spectrometry for ultratrace analysis of pesticide residues in baby food.

PubMed

Hercegová, Andrea; Dömötörová, Milena; Kruzlicová, Dása; Matisová, Eva

2006-05-01

Four sample preparation techniques were compared for the ultratrace analysis of pesticide residues in baby food: (a) modified Schenck's method based on ACN extraction with SPE cleaning; (b) quick, easy, cheap, effective, rugged, and safe (QuEChERS) method based on ACN extraction and dispersive SPE; (c) modified QuEChERS method which utilizes column-based SPE instead of dispersive SPE; and (d) matrix solid phase dispersion (MSPD). The methods were combined with fast gas chromatographic-mass spectrometric analysis. The effectiveness of clean-up of the final extract was determined by comparison of the chromatograms obtained. Time consumption, laboriousness, demands on glassware and working place, and consumption of chemicals, especially solvents, increase in the following order QuEChERS < modified QuEChERS < MSPD < modified Schenck's method. All methods offer satisfactory analytical characteristics at the concentration levels of 5, 10, and 100 microg/kg in terms of recoveries and repeatability. Recoveries obtained for the modified QuEChERS method were lower than for the original QuEChERS. In general the best LOQs were obtained for the modified Schenck's method. Modified QuEChERS method provides 21-72% better LOQs than the original method.

A novel green chemistry method for nonaqueous extraction and high-performance liquid chromatography detection of first-, second-, and third-generation tetracyclines, 4-epitetracycline, and tylosin in animal feeds.

PubMed

Granados-Chinchilla, Fabio; Sánchez, Jorge; García, Fernando; Rodríguez, César

2012-07-25

Although tetracyclines and macrolides are common additives for animal nutrition, methods for their simultaneous determination in animal feeds are nonexistent. By coupling an organic extraction and solid-phase extraction cleanup to a high-performance liquid chromatography separation and a nonaqueous postcolumn derivatization, we succeeded in detecting from 0.2 to 24.0 μg kg(-1) of tetracycline, oxytetracycline, chlortetracycline, doxycycline, tigecycline, and 4-epitetracycline in this complex and heterogeneous matrix. Minocycline and tylosin could also be detected with our procedure, but using UV spectrophotometry (1.5 ≤ LOD ≤ 1.9 mg kg(-1)). Linear responses with correlation coefficients between 0.996 and 0.999 were obtained for all analytes in the 0.5-10 mg kg(-1) concentration range. Average recoveries between 59 and 97% and between 98 and 102% were obtained for the tetracyclines and tylosin, respectively. Replicate standard deviations were typically below 5%. When this method was applied to 20 feeds marketed in Costa Rica, we detected labeling inconsistencies, banned mixtures of tetracyclines, and tetracycline concentrations that contravene international regulation.

Development of a simple one-pot extraction method for various drugs and metabolites of forensic interest in blood by modifying the QuEChERS method.

PubMed

Matsuta, Shuntaro; Nakanishi, Keiko; Miki, Akihiro; Zaitsu, Kei; Shima, Noriaki; Kamata, Tooru; Nishioka, Hiroshi; Katagi, Munehiro; Tatsuno, Michiaki; Tsuboi, Kento; Tsuchihashi, Hitoshi; Suzuki, Koichi

2013-10-10

A rapid and convenient extraction method has been developed for the determination of various drugs and metabolites of forensic interest in blood by modifying the dispersive solid-phase extraction method "QuEChERS". The following 13 analytes with various chemical properties were used for the method development and its validation: amphetamine, methamphetamine, zolpidem, the carboxylate-form major metabolite of zolpidem M-1, flunitrazepam, 7-aminoflunitrazepam, phenobarbital, triazolam, α-hydroxytriazolam, brotizolam, α-hydroxybrotizolam, chlorpromazine, and promethazine. The modification of the QuEChERS method includes the use of relatively large amounts of inorganic salts in order to coagulate blood, which allows easy isolation of the organic extract phase. A combination of 100 mg anhydrous magnesium sulfate as a dehydrating agent, 50mg sodium chloride as a salting-out agent, and 500 μL acetonitrile containing 0.2% acetic acid as the organic solvent provided the optimum conditions for processing a 100 μL whole blood sample. The recoveries of the analytes spiked into whole blood at 0.5 μg/mL ranged between 59% and 93%. Although the addition of the graphitized carbon Envi-carb for cleanup decreased the recoveries of zolpidem and its carboxylate-form metabolite M-1, it was very effective in avoiding interferences by cholesterol. The present method can provide a rapid, effective, user-friendly, and relatively hygienic method for the simultaneous extraction of a wide range of drugs and metabolites in whole blood specimens. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Field scale DNAPLs transport under nonequilibrium sorption conditions.

PubMed

Ahmed, Ashraf A; Chen, Daoyi

2006-01-01

The purpose of this work is to study the desorption of dense nonaqueous phase liquids (DNAPLs), TCE in particular, from solid particles in field scale heterogeneous aquifers upon their remediation. A computer program, capable of simulating the fate and transport of NAPLs in porous media, has been developed to work under nonequilibrium sorption conditions. The model has been applied to a field scale site at Hill Air Force Base, Utah, which has been contaminated by DNAPLs. The simulated domain was 155 ft (47.25 m) long, 60 ft (18.29 m) wide, and 15.5 ft (4.72 m) thick. This thickness represents only the saturated zone of the aquifer. Changes in permeability, grain size distribution, and sorptive properties throughout the site have been incorporated into the model. Immediately after the aquifer cleanup, the DNAPL concentration in the aqueous phase was assumed to be zero, and this was considered the start-off time for the simulation. Results show that, with an increase in time, the TCE diffused out of the solid particles, forming a plume. The rate of contaminant diffusion was observed to be very fast at the start, followed by a very slow stage, with a number of years required for substantial desorption of the contaminant from the solid particles. There were local variations in contaminant concentration in the fluid phase across the site due to aquifer heterogeneity. A comparison between numerical results and water samples taken from the site after the end of the cleanup operation is also presented.

Analysis of ibuprofen and its main metabolites in roots, shoots, and seeds of cowpea (Vigna unguiculata L. Walp) using liquid chromatography-quadrupole time-of-flight mass spectrometry: uptake, metabolism, and translocation.

PubMed

Picó, Yolanda; Alvarez-Ruiz, Rodrigo; Wijaya, Leonard; Alfarhan, Ahmed; Alyemeni, Mohammed; Barceló, Damià

2018-01-01

A liquid chromatography quadruple time-of-flight mass spectrometry (LC-QqTOF-MS/MS) method was developed for simultaneous quantitative analysis of ibuprofen (IBU), 1- and 2-hydroxyibuprofen (1-OH IBU and 2-OH IBU), and carboxyibuprofen (CBX IBU) while preserving the ability of the instrument to get precursor and product ion mass spectra of non-target compounds. The trigger was the precursor ions reaching 100 cps intensity. Sample preparation was carried out by ultrasound solid-liquid extraction with methanol as extraction solvent at pH < 2 followed by solid-phase extraction (SPE) clean-up using STRATA-X cartridges and methanol as an eluent. Linearity was obtained in the range 50-10,000 ng mL -1 for IBU, each OH IBU and CBX IBU (r ≥ 0.99). The proposed method was satisfactorily validated showing absolute recoveries of > 70% for all target analytes at low and high concentration levels. The lowest limit of quantification was < 50 ng g -1 in plant. This method was applied to investigate IBP behavior in cowpea (Vigna unguiculata (L.) Walp) treated at high IBU concentrations and its presence in vegetables irrigated with treated water. Up to 46 metabolites, mostly hydroxylated metabolites and conjugates with hexosides and amino acids, were identified. The most abundant metabolites were also identified in an eggplant sample. Graphical Abstract ᅟ Ibuprofen metabolite identification.

Determination of organophosphorus pesticides and their major degradation product residues in food samples by HPLC-UV.

PubMed

Peng, Guilong; He, Qiang; Lu, Ying; Mmereki, Daniel; Zhong, Zhihui

2016-10-01

A simple method based on dispersive solid-phase extraction (DSPE) and dispersive liquid-liquid microextraction method based on solidification of floating organic droplets (DLLME-SFO) was developed for the extraction of chlorpyrifos (CP), chlorpyrifos-methyl (CPM), and their main degradation product 3,5,6-trichloro-2-pyridinol (TCP) in tomato and cucumber samples. The determination was carried out by high performance liquid chromatography with ultraviolet detection (HPLC-UV). In the DSPE-DLLME-SFO, the analytes were first extracted with acetone. The clean-up of the extract by DSPE was carried out by directly adding activated carbon sorbent into the extract solution, followed by shaking and filtration. Under the optimum conditions, the proposed method was sensitive and showed a good linearity within a range of 2-500 ng/g, with the correlation coefficients (r) varying from 0.9991 to 0.9996. The enrichment factors ranged from 127 to 138. The limit of detections (LODs) were in the range of 0.12-0.68 ng/g, and the relative standard deviations (RSDs) for 50 ng/g of each analytes in tomato samples were in the range of 3.25-6.26 % (n = 5). The proposed method was successfully applied for the extraction and determination of the mentioned analytes residues in tomato and cucumber samples, and satisfactory results were obtained.

An automated online turboflow cleanup LC/MS/MS method for the determination of 11 plasticizers in beverages and milk.

PubMed

Ates, Ebru; Mittendorf, Klaus; Senyuva, Hamide

2013-01-01

An automated sample preparation technique involving cleanup and analytical separation in a single operation using an online coupled TurboFlow (RP-LC system) is reported. This method eliminates time-consuming sample preparation steps that can be potential sources for cross-contamination in the analysis of plasticizers. Using TurboFlow chromatography, liquid samples were injected directly into the automated system without previous extraction or cleanup. Special cleanup columns enabled specific binding of target compounds; higher MW compounds, i.e., fats and proteins, and other matrix interferences with different chemical properties were removed to waste, prior to LC/MS/MS. Systematic stepwise method development using this new technology in the food safety area is described. Selection of optimum columns and mobile phases for loading onto the cleanup column followed by transfer onto the analytical column and MS detection are critical method parameters. The method was optimized for the assay of 10 phthalates (dimethyl, diethyl, dipropyl, butyl benzyl, diisobutyl, dicyclohexyl, dihexyl, diethylhexyl, diisononyl, and diisododecyl) and one adipate (diethylhexyl) in beverages and milk.

Simple extraction method for quantification of phenothiazine residues in pork muscle using liquid chromatography-triple quadrupole tandem mass spectrometry.

PubMed

Zhang, Dan; Park, Jin-A; Kim, Seong-Kwan; Cho, Sang-Hyun; Cho, Soo-Min; Shim, Jae-Han; Kim, Jin-Suk; Abd El-Aty, A M; Shin, Ho-Chul

2017-06-01

In this study, an analytical method was developed for quantification of residues of the anthelmintic drug phenothiazine (PTZ) in pork muscle using liquid chromatography-tandem mass spectrometry. Muscles were extracted using 0.2% formic acid and 10 mm ammonium formate in acetonitrile, defatted and purified using n-hexane. The drug was well separated on a Waters XBridge™ C 18 analytical column using a binary solvent system consisting of 0.2% formic acid and 10 mm ammonium formate in ultrapure water (A) and acetonitrile (B). Good linearity was achieved over a six-point concentration range in matrix-matched calibration with determination coefficient =0.9846. Fortified pork muscle having concentrations equivalent to and double the limit of quantification (1 ng/g) yielded recovery ranges between 100.82 and 104.03% and relative standard deviations <12%. Samples (n = 5) collected from large markets located in Seoul City tested negative for PTZ residue. In conclusion, 0.2% formic acid and ammonium formate in acetonitrile can effectively extract PTZ from pork muscle without solid-phase extraction, a step normally required for cleanup before analysis and the validated method can be used for routine analysis to ensure the quality of animal products. Copyright © 2016 John Wiley & Sons, Ltd.

Determination of anthelmintic drug residues in milk using ultra high performance liquid chromatography-tandem mass spectrometry with rapid polarity switching.

PubMed

Whelan, Michelle; Kinsella, Brian; Furey, Ambrose; Moloney, Mary; Cantwell, Helen; Lehotay, Steven J; Danaher, Martin

2010-07-02

A new UHPLC-MS/MS (ultra high performance liquid chromatography coupled to tandem mass spectrometry) method was developed and validated to detect 38 anthelmintic drug residues, consisting of benzimidazoles, avermectins and flukicides. A modified QuEChERS-type extraction method was developed with an added concentration step to detect most of the analytes at <1 microg kg(-1) levels in milk. Anthelmintic residues were extracted into acetonitrile using magnesium sulphate and sodium chloride to induce liquid-liquid partitioning followed by dispersive solid phase extraction for cleanup. The extract was concentrated into dimethyl sulphoxide, which was used as a keeper to ensure analytes remain in solution. Using rapid polarity switching in electrospray ionisation, a single injection was capable of detecting both positively and negatively charged ions in a 13 min run time. The method was validated at two levels: the unapproved use level and at the maximum residue level (MRL) according to Commission Decision (CD) 2002/657/EC criteria. The decision limit (CCalpha) of the method was in the range of 0.14-1.9 and 11-123 microg kg(-1) for drugs validated at unapproved and MRL levels, respectively. The performance of the method was successfully verified for benzimidazoles and levamisole by participating in a proficiency study.

Development of a sensitive and selective liquid chromatography-mass spectrometry method for high throughput analysis of paralytic shellfish toxins using graphitised carbon solid phase extraction.

PubMed

Boundy, Michael J; Selwood, Andrew I; Harwood, D Tim; McNabb, Paul S; Turner, Andrew D

2015-03-27

Routine regulatory monitoring of paralytic shellfish toxins (PST) commonly employs oxidative derivitisation and complex liquid chromatography fluorescence detection methods (LC-FL). The pre-column oxidation LC-FL method is currently implemented in New Zealand and the United Kingdom. When using this method positive samples are fractionated and two different oxidations are required to confirm the identity and quantity of each PST analogue present. There is a need for alternative methods that are simpler, provide faster turnaround times and have improved detection limits. Hydrophilic interaction liquid chromatography (HILIC) HPLC-MS/MS analysis of PST has been used for research purposes, but high detection limits and substantial sample matrix issues have prevented it from becoming a viable alternative for routine monitoring purposes. We have developed a HILIC UPLC-MS/MS method for paralytic shellfish toxins with an optimised desalting clean-up procedure on inexpensive carbon solid phase extraction cartridges for reduction of matrix interferences. This represents a major technical breakthrough and allows sensitive, selective and rapid analysis of paralytic shellfish toxins from a variety of sample types, including many commercially produced bivalve molluscan shellfish species. Additionally, this analytical approach avoids the need for complex calculations to determine sample toxicity, as unlike other methods each PST analogue is able to be quantified as a single resolved peak. This article presents the method development and optimisation information. A thorough single laboratory validation study has subsequently been performed and this data will be presented elsewhere. Copyright © 2015 Elsevier B.V. All rights reserved.

Spectrophotometric total reducing sugars assay based on cupric reduction.

PubMed

Başkan, Kevser Sözgen; Tütem, Esma; Akyüz, Esin; Özen, Seda; Apak, Reşat

2016-01-15

As the concentration of reducing sugars (RS) is controlled by European legislation for certain specific food and beverages, a simple and sensitive spectrophotometric method for the determination of RS in various food products is proposed. The method is based on the reduction of Cu(II) to Cu(I) with reducing sugars in alkaline medium in the presence of 2,9-dimethyl-1,10-phenanthroline (neocuproine: Nc), followed by the formation of a colored Cu(I)-Nc charge-transfer complex. All simple sugars tested had the linear regression equations with almost equal slope values. The proposed method was successfully applied to fresh apple juice, commercial fruit juices, milk, honey and onion juice. Interference effect of phenolic compounds in plant samples was eliminated by a solid phase extraction (SPE) clean-up process. The method was proven to have higher sensitivity and precision than the widely used dinitrosalicylic acid (DNS) colorimetric method. Copyright © 2015 Elsevier B.V. All rights reserved.

Determination of active components of Ginkgo biloba in human urine by capillary high-performance liquid chromatography/mass spectrometry with on-line column-switching purification.

PubMed

Ding, Shujing; Dudley, Ed; Chen, Lijuan; Plummer, Sue; Tang, Jiandong; Newton, Russell P; Brenton, A Gareth

2006-01-01

Ginkgo biloba is one of the most popular herbal nutritional supplements, with terpene lactones and flavonoids being the two major active components. An on-line purification high-performance liquid chromatography/mass spectrometry (HPLC/MS) method was successfully developed for the quantitative determination of flavonoids and terpene lactones excreted in human urine after ingesting the herbal supplement. Satisfactory separation was obtained using a C18 capillary column made in-house with sample clean-up and pre-concentration achieved using a C18 pre-column with column switching. High selectivity and limits of detection of 1-18 ng/mL were achieved using a selected ion monitoring (SIM) scan in negative ion mode; the on-line solid-phase extraction (SPE) recovery of the active components in Ginkgo biloba determined in this study was greater than 75%. Copyright 2006 John Wiley & Sons, Ltd.

Water-Soluble Dried Blood Spot in Protein Analysis: A Proof-of-Concept Study.

PubMed

Rosting, Cecilie; Gjelstad, Astrid; Halvorsen, Trine Grønhaug

2015-08-04

In the present work human chorionic gonadotropin (hCG) was used as a model protein in a proof-of-concept study combining water-soluble dried blood spot (DBS) material in liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based protein analysis. A water-soluble material consisting of commercially available carboxymethyl cellulose (CMC) was evaluated as sampling material for this purpose. The material dissolved readily at physiological pH. Different sample preparation methods were evaluated, and in the final method, 15 μL of whole blood was deposited and dried on CMC before the whole spot was dissolved prior to cleanup by immunoaffinity extraction, tryptic digest, and preconcentration by solid-phase extraction (SPE). The results indicated complete dissolution of hCG from the spots, acceptable limit of detection (LOD) (0.1 IU/mL), linearity (R(2) = 0.959), accuracy (16%), and precision (≤22%). Long-term stability (45 days) of hCG in dried spots at reduced temperatures (≤8 °C) was also demonstrated. The analyte recovery was comparable to the commercially available nonsolvable cellulose material (FTA DMPK-C card).

Analysis of oxytetracycline in water using a portable analyzer

NASA Astrophysics Data System (ADS)

Chen, Guoying; Braden, Susan; Qin, Feng

2006-10-01

Oxytetracycline (OTC) is extensively used in aquaculture worldwide for preventive and therapeutic purposes. Most of the drug, however, is discharged into the marine environment due to leaching from medicated feed and poor gastrointestinal (GI) absorption. Without exposure to sun light OTC has a long lifetime in the marine environment, therefore it is important to monitor and study its occurrence, distribution, fate and impact on the ecosystem. A portable tetracycline (TC) analyzer was developed in this laboratory for this purpose based on europium-sensitized luminescence. In this study, an assay method is developed for OTC analysis in water using this instrument. Water samples are filtered with glass wool; and solid phase extraction (SPE) is performed using Oasis HLB cartridges for OTC extraction and cleanup. Following reagent application, the samples are excited by 385 nm LED pulses; and time-resolved luminescence (TRL) is measured at 610 nm by a photomultiplier tube. A 0-3 ppm linear dynamic range (r2 = 0.9988) and a 0.021 ppb limit of detection were achieved with a typical <5% relative standard deviation.

Development of magnetic molecularly imprinted polymers for selective extraction: determination of citrinin in rice samples by liquid chromatography with UV diode array detection.

PubMed

Urraca, Javier L; Huertas-Pérez, José F; Cazorla, Guillermo Aragoneses; Gracia-Mora, Jesus; García-Campaña, Ana M; Moreno-Bondi, María Cruz

2016-04-01

In this work, we report the synthesis of novel magnetic molecularly imprinted polymers (m-MIPs) and their application to the selective extraction of the mycotoxin citrinin (CIT) from food samples. The polymers were prepared by surface imprinting of Fe3O4 nanoparticles, using 2-naphtholic acid (2-NA) as template molecule, N-3,5-bis(trifluoromethyl)phenyl-N'-4-vinylphenyl urea and methacrylamide as functional monomers and ethyleneglycol dimethacrylate as cross-linker. The resulting material was characterized by transmission electron microscopy (TEM), and X-ray diffraction (XRD) and Fourier transform infrared spectroscopies (FT-IR). The polymers were used to develop a solid-phase extraction method (m-MISPE) for the selective recovery of CIT from rice extracts prior to its determination by HPLC with UV diode array detection. The method involves ultrasound-assisted extraction of the mycotoxin from rice samples with (7:3, v/v) methanol/water, followed by sample cleanup and preconcentration with m-MIP. The extraction (washing and elution) conditions were optimized and their optimal values found to provide CIT recoveries of 94-98 % with relative standard deviations (RSD) less than 3.4 % (n = 3) for preconcentrated sample extracts (5 mL) fortified with the analyte at concentrations over the range 25-100 μg kg(-1). Based on the results, the application of the m-MIPs facilitates the accurate and efficient determination of CIT in rice extracts.

Characterisation of chamomile volatiles by simultaneous distillation solid-phase extraction in comparison to hydrodistillation and simultaneous distillation extraction.

PubMed

Krüger, Hans

2010-05-01

A new method for complete separation of steam-volatile organic compounds is described using the example of chamomile flowers. This method is based on the direct combination of hydrodistillation and solid-phase extraction in a circulation apparatus. In contrast to hydrodistillation and simultaneous distillation extraction (SDE), an RP-18 solid phase as adsorptive material is used rather than a water-insoluble solvent. Therefore, a prompt and complete fixation of all volatiles takes place, and the circulation of water-soluble bisabololoxides as well as water-soluble and thermolabile en-yne-spiroethers is inhibited. This so-called simultaneous distillation solid-phase extraction (SD-SPE) provides extracts that better characterise the real composition of the vapour phase, as well as the composition of inhalation vapours, than do SDE extracts or essential oils obtained by hydrodistillation. The data indicate that during inhalation therapy with chamomile, the bisabololoxides and spiroethers are more strongly involved in the inhaling activity than so far assumed. Georg Thieme Verlag KG Stuttgart New York.

Fuel spill identification using solid-phase extraction and solid-phase microextraction. 1. Aviation turbine fuels.

PubMed

Lavine, B K; Brzozowski, D M; Ritter, J; Moores, A J; Mayfield, H T

2001-12-01

The water-soluble fraction of aviation jet fuels is examined using solid-phase extraction and solid-phase microextraction. Gas chromatographic profiles of solid-phase extracts and solid-phase microextracts of the water-soluble fraction of kerosene- and nonkerosene-based jet fuels reveal that each jet fuel possesses a unique profile. Pattern recognition analysis reveals fingerprint patterns within the data characteristic of fuel type. By using a novel genetic algorithm (GA) that emulates human pattern recognition through machine learning, it is possible to identify features characteristic of the chromatographic profile of each fuel class. The pattern recognition GA identifies a set of features that optimize the separation of the fuel classes in a plot of the two largest principal components of the data. Because principal components maximize variance, the bulk of the information encoded by the selected features is primarily about the differences between the fuel classes.

Use of a novel cation-exchange restricted-access material for automated sample clean-up prior to the determination of basic drugs in plasma by liquid chromatography.

PubMed

Chiap, P; Rbeida, O; Christiaens, B; Hubert, Ph; Lubda, D; Boos, K S; Crommen, J

2002-10-25

A new kind of silica-based restricted-access material (RAM) has been tested in pre-columns for the on-line solid-phase extraction (SPE) of basic drugs from directly injected plasma samples before their quantitative analysis by reversed-phase liquid chromatography (LC), using the column switching technique. The outer surface of the porous RAM particlescontains hydrophilic diol groups while sulphonic acid groups are bound to the internal surface, which gives the sorbent the properties of a strong cation exchanger towards low molecular mass compounds. Macromolecules such as proteins have no access to the internal surface of the pre-column due to their exclusion from the pores and are then flushed directly out. The retention capability of this novel packing material has been tested for some hydrophilic basic drugs, such as atropine, fenoterol, ipratropium, procaine, sotalol and terbutaline, used as model compounds. The influence of the composition of the washing liquid on the retention of the analytes in the pre-column has been investigated. The elution profiles of the different compounds and the plasma matrix as well as the time needed for the transfer of the analytes from the pre-column to the analytical column were determined in order to deduce the most suitable conditions for the clean-up step and develop on-line methods for the LC determination of these compounds in plasma. The cationic exchange sorbent was also compared to another RAM, namely RP-18 ADS (alkyl diol silica) sorbent with respect to retention capability towards basic analytes.

Analysis and stability study of retinoids in pharmaceuticals by LC with fluorescence detection.

PubMed

Gatti, R; Gioia, M G; Cavrini, V

2000-08-01

Liquid chromatographic (HPLC) methods with fluorescence detection at different wavelengths were developed for measurements of retinoic acids (13-cis and all-trans) in pharmaceutical dosage forms and components of 'retinoid solution' (all-trans retinoic acid, vitamin A palmitate and beta-carotene), a galenical of 'Di Bella therapy', using reversed phase columns under isocratic conditions. The stability of all-trans retinoic acid in cream and all-trans retinoic acid and vitamin A palmitate in 'retinoid solution' was investigated. Solid-phase extraction (SPE), using C18 sorbent was applied to the analysis of retinoic acids (9-cis, 13-cis and all-trans) in the 'retinoid solution' to obtain a practical and reliable sample clean-up. The results showed that these preparations (cream and solution) can be conveniently stored in the dark (t.a. or 2-8 degrees C): under these conditions about 86-87% of the all-trans retinoic acid initial concentration in both formulations and about 73-78% of vitamin A palmitate in the 'retinoid solution' remained after 90 days, while under sunlight exposure rapid degradation of the drugs was observed.

Purification of Derivatized Oligosaccharides by Solid Phase Extraction for Glycomic Analysis

PubMed Central

Zhang, Qiwei; Li, Henghui; Feng, Xiaojun; Liu, Bi-Feng; Liu, Xin

2014-01-01

Profiling of glycans released from proteins is very complex and important. To enhance the detection sensitivity, chemical derivatization is required for the analysis of carbohydrates. Due to the interference of excess reagents, a simple and reliable purification method is usually necessary for the derivatized oligosaccharides. Various SPE based methods have been applied for the clean-up process. To demonstrate the differences among these methods, seven types of self-packed SPE cartridges were systematically compared in this study. The optimized conditions were determined for each type of cartridge and it was found that microcrystalline cellulose was the most appropriate SPE material for the purification of derivatized oligosaccharide. Normal phase HPLC analysis of the derivatized maltoheptaose was realized with a detection limit of 0.12 pmol (S N−1 = 3) and a recovery over 70%. With the optimized SPE method, relative quantification analysis of N-glycans from model glycoproteins were carried out accurately and over 40 N-glycans from human serum samples were determined regardless of the isomers. Due to the high stability and sensitivity, microcrystalline cellulose cartridge showed potential applications in glycomics analysis. PMID:24705408

Comparison of the solid-phase extraction efficiency of a bounded and an included cyclodextrin-silica microporous composite for polycyclic aromatic hydrocarbons determination in water samples.

PubMed

Mauri-Aucejo, Adela; Amorós, Pedro; Moragues, Alaina; Guillem, Carmen; Belenguer-Sapiña, Carolina

2016-08-15

Solid-phase extraction is one of the most important techniques for sample purification and concentration. A wide variety of solid phases have been used for sample preparation over time. In this work, the efficiency of a new kind of solid-phase extraction adsorbent, which is a microporous material made from modified cyclodextrin bounded to a silica network, is evaluated through an analytical method which combines solid-phase extraction with high-performance liquid chromatography to determine polycyclic aromatic hydrocarbons in water samples. Several parameters that affected the analytes recovery, such as the amount of solid phase, the nature and volume of the eluent or the sample volume and concentration influence have been evaluated. The experimental results indicate that the material possesses adsorption ability to the tested polycyclic aromatic hydrocarbons. Under the optimum conditions, the quantification limits of the method were in the range of 0.09-2.4μgL(-1) and fine linear correlations between peak height and concentration were found around 1.3-70μgL(-1). The method has good repeatability and reproducibility, with coefficients of variation under 8%. Due to the concentration results, this material may represent an alternative for trace analysis of polycyclic aromatic hydrocarbons in water trough solid-phase extraction. Copyright © 2016 Elsevier B.V. All rights reserved.

Analysis of polycyclic aromatic hydrocarbons extracted from air particulate matter using a temperature programmable injector coupled to GC-C-IRMS.

PubMed

Mikolajczuk, Agnieszka; Przyk, Elzbieta Perez; Geypens, Benny; Berglund, Michael; Taylor, Philip

2010-03-01

Compound specific isotopic analysis (CSIA) can provide information about the origin of analysed compounds - in this case, polycyclic aromatic hydrocarbons (PAHs). In the study, PAHs were extracted from three dust samples: winter and summer filter dust and tunnel dust. The measurement was performed using the method validated in our laboratory using pure, solid compounds and EPA 610 reference assortment. CSIA required an appropriate clean-up method to avoid an unresolved complex in the gas chromatographic analysis usually found in the chromatography of PAHs. Extensive sample clean-up for this particular matrix was found to be necessary to obtain good gas chromatography-combustion-isotope ratio mass spectrometry analysis results. The sample purification method included two steps in which the sample is cleaned up and the aliphatic and aromatic hydrocarbons are separated. The concentration of PAHs in the measured samples was low; so a large volume injection technique (100 microl) was applied. The delta(VPDB)(13)C was measured with a final uncertainty smaller than 1 per thousand. Comparison of the delta(VPDB)(13)C signatures of PAHs extracted from different dust samples was feasible with this method and, doing so, significant differences were observed.

Quantification of VX Nerve Agent in Various Food Matrices by Solid-Phase Extraction Ultra-Performance Liquid ChromatographyTime-of-Flight Mass Spectrometry

DTIC Science & Technology

2016-04-01

QUANTIFICATION OF VX NERVE AGENT IN VARIOUS FOOD MATRICES BY SOLID-PHASE EXTRACTION ULTRA-PERFORMANCE...TITLE AND SUBTITLE Quantification of VX Nerve Agent in Various Food Matrices by Solid-Phase Extraction Ultra-Performance Liquid Chromatography... food matrices. The mixed-mode cation exchange (MCX) sorbent and Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) methods were used for

Quantification of Complex Polycyclic Aromatic Hydrocarbon Mixtures in Standard Reference Materials Using GC×GC/ToF-MS

PubMed Central

Manzano, Carlos; Hoh, Eunha; Massey Simonich, Staci L.

2014-01-01

This research is the first to quantify complex PAH mixtures in NIST SRMs using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC/ToF-MS), with and without extract cleanup, and reports previously unidentified PAH isomers in the NIST SRMs. We tested a novel, high orthogonality GC column combination (LC-50×NSP-35), as well as with a commonly used column combination (Rtx-5ms×Rxi-17) for the quantification of a complex mixture of 85 different PAHs, including parent (PAHs), alkyl- (MPAHs), nitro- (NPAHs), oxy- (OPAHs), thio- (SPAHs), bromo- (BrPAHs), and chloro-PAHs (ClPAHs) in extracts from two standard reference materials: NIST SRM1650b (diesel particulate matter), with cleanup and NIST SRM1975 (diesel particulate extract), with and without extract cleanup. The LC-50×NSP-35 column combination resulted in an average absolute percent difference of 33.8%, 62.2% and 30.8% compared to the NIST certified PAH concentrations for NIST SRM1650b, NIST SRM1975 with cleanup and NIST SRM1975 without cleanup, while the Rtx-5ms×Rxi-17 resulted in an absolute percent difference of 38.6%, 67.2% and 79.6% for NIST SRM1650b, NIST SRM1975 with cleanup and NIST SRM1975 without cleanup, respectively. This GC×GC/ToF-MS method increases the number of PAHs detected and quantified in complex environmental extracts using a single chromatographic run. Without clean-up, 7 additional compounds were detected and quantified in NIST SRM1975 using the LC-50×NSP-35 column combination. These results suggest that the use of the LC-50×NSP-35 column combination in GC×GC/ToF-MS not only results in better chromatographic resolution and greater orthogonality for the separation of complex PAH mixtures, but can also be used for the accurate quantification of complex PAH mixtures in environmental extracts without cleanup. PMID:23932031

Characterization of rhamnolipids by liquid chromatography/mass spectrometry after solid-phase extraction.

PubMed

Behrens, Beate; Engelen, Jeannine; Tiso, Till; Blank, Lars Mathias; Hayen, Heiko

2016-04-01

Rhamnolipids are surface-active agents with a broad application potential that are produced in complex mixtures by bacteria of the genus Pseudomonas. Analysis from fermentation broth is often characterized by laborious sample preparation and requires hyphenated analytical techniques like liquid chromatography coupled to mass spectrometry (LC-MS) to obtain detailed information about sample composition. In this study, an analytical procedure based on chromatographic method development and characterization of rhamnolipid sample material by LC-MS as well as a comparison of two sample preparation methods, i.e., liquid-liquid extraction and solid-phase extraction, is presented. Efficient separation was achieved under reversed-phase conditions using a mixed propylphenyl and octadecylsilyl-modified silica gel stationary phase. LC-MS/MS analysis of a supernatant from Pseudomonas putida strain KT2440 pVLT33_rhlABC grown on glucose as sole carbon source and purified by solid-phase extraction revealed a total of 20 congeners of di-rhamnolipids, mono-rhamnolipids, and their biosynthetic precursors 3-(3-hydroxyalkanoyloxy)alkanoic acids (HAAs) with different carbon chain lengths from C8 to C14, including three rhamnolipids with uncommon C9 and C11 fatty acid residues. LC-MS and the orcinol assay were used to evaluate the developed solid-phase extraction method in comparison with the established liquid-liquid extraction. Solid-phase extraction exhibited higher yields and reproducibility as well as lower experimental effort.

Separation of phenolic acids from sugarcane rind by online solid-phase extraction with high-speed counter-current chromatography.

PubMed

Geng, Ping; Fang, Yingtong; Xie, Ronglong; Hu, Weilun; Xi, Xingjun; Chu, Qiao; Dong, Genlai; Shaheen, Nusrat; Wei, Yun

2017-02-01

Sugarcane rind contains some functional phenolic acids. The separation of these compounds from sugarcane rind is able to realize the integrated utilization of the crop and reduce environment pollution. In this paper, a novel protocol based on interfacing online solid-phase extraction with high-speed counter-current chromatography (HSCCC) was established, aiming at improving and simplifying the process of phenolic acids separation from sugarcane rind. The conditions of online solid-phase extraction with HSCCC involving solvent system, flow rate of mobile phase as well as saturated extent of absorption of solid-phase extraction were optimized to improve extraction efficiency and reduce separation time. The separation of phenolic acids was performed with a two-phase solvent system composed of butanol/acetic acid/water at a volume ratio of 4:1:5, and the developed online solid-phase extraction with HSCCC method was validated and successfully applied for sugarcane rind, and three phenolic acids including 6.73 mg of gallic acid, 10.85 mg of p-coumaric acid, and 2.78 mg of ferulic acid with purities of 60.2, 95.4, and 84%, respectively, were obtained from 150 mg sugarcane rind crude extracts. In addition, the three different elution methods of phenolic acids purification including HSCCC, elution-extrusion counter-current chromatography and back-extrusion counter-current chromatography were compared. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Microwave-assisted extraction and ultrasonic extraction to determine polycyclic aromatic hydrocarbons in needles and bark of Pinus pinaster Ait. and Pinus pinea L. by GC-MS.

PubMed

Ratola, Nuno; Lacorte, Sílvia; Barceló, Damià; Alves, Arminda

2009-01-15

Two different extraction strategies (microwave-assisted extraction (MAE) and ultrasonic extraction (USE)) were tested in the extraction of the 16 US Environmental Protection Agency (EPA) polycyclic aromatic hydrocarbons (PAHs) from pine trees. Extraction of needles and bark from two pine species common in the Iberian Peninsula (Pinus pinaster Ait. and Pinus pinea L.) was optimized using two amounts of sample (1g and 5 g) and two PAHs spiking levels (20 ng/g and 100 ng/g). In all cases, the clean-up procedure following extraction consisted in solid-phase extraction (SPE) with alumina cartridges. Quantification was done by gas chromatography (GC) with mass spectrometry (MS), using five deuterated PAH surrogate standards as internal standards. Limits of detection were globally below 0.2 ng/g. The method was robust for the matrices studied regardless of the extraction procedures. Recovery values between 70 and 130% were reached in most cases, except for high molecular weight PAHs (indeno[1,2,3-cd]pyrene, dibenzo[a,h]anthracene and benzo[ghi]perylene). A field study with naturally contaminated samples from eight sites (four in Portugal and four in Catalonia, Spain) showed that needles are more suitable biomonitors for PAHs, yielding concentrations from 2 to 17 times higher than those found in bark. The levels varied according to the sampling site, with the sum of the individual PAH concentrations between 213 and 1773 ng/g (dry weight). Phenanthrene was the most abundant PAH, followed by fluoranthene, naphthalene and pyrene.

Analysis of 19-nortestosterone residue in animal tissues by ion-trap gas chromatography-tandem mass spectrometry*

PubMed Central

Jiang, Jin-qing; Zhang, Lei; Li, Guang-ling; Zhang, Hai-tang; Yang, Xue-feng; Liu, Jun-wei; Li, Ren-feng; Wang, Zi-liang; Wang, Jian-hua

2011-01-01

A rapid sample treatment procedure for the gas chromatography-tandem mass spectrometry (GC-MS) determination of 19-nortestosterone (19-NT) in animal tissues has been developed. In our optimized procedures, enzymatic hydrolysis with β-glucuronidase from Escherichia coli was performed in an acetate buffer (pH 5.2, 0.2 mol/L). Next, the homogenate was mixed with methanol and heated at 60 °C for 15 min, then placed in an ice-bath at −18 °C for 2 h. After liquid-liquid extraction with n-hexane, the analytes were subjected to a normal-phase solid phase extraction (SPE) C18 cartridge for clean-up. The dried organic extracts were derivatized with heptafluorobutyric anhydride (HFBA), and then the products were injected into GC-MS. Using electron impact mass spectrometry (EI-MS) with positive chemical ionization (PCI), four diagnostic ions (m/z 666, 453, 318, and 306) were determined. A standard calibration curve over the concentration range of 1–20 ng/g was reached, with Y=467 084X−68 354 (R 2=0.999 7) for 19-NT, and the detection limit was 0.3 ng. When applied to spiked samples collected from bovine and ovine, the recoveries ranged from 63% to 101% with relative standard deviation (RSD) between 2.7% and 8.9%. The procedure is a highly efficient, sensitive, and more economical method which offers considerable potential to resolve cases of suspected nandrolone doping in husbandry animals. PMID:21634039

The National LUST Cleanup Backlog: A Study of Opportunities

EPA Pesticide Factsheets

To understand the makeup of UST releases remaining and why the pace of cleanups is slowing, EPA undertook a two-phase, data-driven analysis of the cleanups remaining as of 2006 (Phase 1) and 2009 (Phase 2).

Aptamer-functionalized Fe3 O4 magnetic nanoparticles as a solid-phase extraction adsorbent for the selective extraction of berberine from Cortex phellodendri.

PubMed

Jiang, Ling-Feng; Chen, Bo-Cheng; Chen, Ben; Li, Xue-Jian; Liao, Hai-Lin; Zhang, Wen-Yan; Wu, Lin

2017-07-01

The extraction adsorbent was fabricated by immobilizing the highly specific recognition and binding of aptamer onto the surface of Fe 3 O 4 magnetic nanoparticles, which not only acted as recognition elements to recognize and capture the target molecule berberine from the extract of Cortex phellodendri, but also could favor the rapid separation and purification of the bound berberine by using an external magnet. The developed solid-phase extraction method in this work was useful for the selective extraction and determination of berberine in Cortex phellodendri extracts. Various conditions such as the amount of aptamer-functionalized Fe 3 O 4 magnetic nanoparticles, extraction time, temperature, pH value, Mg 2+ concentration, elution time and solvent were optimized for the solid-phase extraction of berberine. Under optimal conditions, the purity of berberine extracted from Cortex phellodendri was as high as 98.7% compared with that of 4.85% in the extract, indicating that aptamer-functionalized Fe 3 O 4 magnetic nanoparticles-based solid-phase extraction method was very effective for berberine enrichment and separation from a complex herb extract. The applicability and reliability of the developed solid-phase extraction method were demonstrated by separating berberine from nine different concentrations of one Cortex phellodendri extract. The relative recoveries of the spiked solutions of all the samples were between 95.4 and 111.3%, with relative standard deviations ranging between 0.57 and 1.85%. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of Parabens by Injection-Port Derivatization Coupled With Gas-Chromatography-Mass Spectrometry and Matrix Solid Phase Dispersion

NASA Astrophysics Data System (ADS)

Djatmika, Rosalina; Ding, Wang-Hsien; Sulistyarti, Hermin

2018-01-01

A rapid determination of four parabens preservatives (methyl paraben, ethyl paraben, propyl paraben, and butyl paraben) in marketed seafood is presented. Analytes were extracted and purified using matrix solid-phase dispersion (MSPD) method, followed by Injection port acylation gas chromatography-mass spectrometry (GC-MS) with acetic anhydride reagent. In this method, acylation of parabens was performed by acetic anhydride at GC injection-port generating reduction of the time-consuming sample-processing steps, and the amount of toxic reagents and solvents. The parameters affecting this method such as injection port temperature, purge-off time and acylation (acetic anhydride) volume were studied. In addition, the MSPD influence factors (including the amount of dispersant and clean-up co-sorbent, as well as the volume of elution solvent) were also investigated. After MSPD method and Injection port acylation applied, good linearity of analytes was achieved. The limits of quantitation (LOQs) were 0.2 to 1.0 ng/g (dry weight). Compared with offline derivatization commonly performed, injection port acylation employs a rapid, simple, low-cost and environmental-friendly derivatization process. The optimized method has been successfully applied for the analysis of parabens in four kind of marketed seafood. Preliminary results showed that the total concentrations of four selected parabens ranged from 16.7 to 44.7 ng/g (dry weight).

[Determination of lead in edible salt with solid-phase extraction and GFAAS].

PubMed

Zhao, Xin; Zhou, Shuang; Ma, Lan; Yang, Dajin

2013-01-01

Establishing a method for determination of lead in salt with solid-phase extraction and GFAAS. Salt sample was diluted to a certain volume directly with ammonium acetate, then the sample solution was filtered through the solid phase extraction column which has been pre-activated. Lead ions were retained, and the sodium chloride matrix was removed. After elution, the collected lead ions was determined by graphite furnace atomic absorption spectrometry in 257.4 nm. This method can be used effectively to wipe off the sodium chloride in matrix. The limit of detection was 0.7 microg/kg and the limit of quantification was 2 microg/kg. Solid phase extraction technique can be used effectively to reduce the interference in matrix and improves the accuracy and reproducibility of detection.

Recent Application of Solid Phase Based Techniques for Extraction and Preconcentration of Cyanotoxins in Environmental Matrices.

PubMed

Mashile, Geaneth Pertunia; Nomngongo, Philiswa N

2017-03-04

Cyanotoxins are toxic and are found in eutrophic, municipal, and residential water supplies. For this reason, their occurrence in drinking water systems has become a global concern. Therefore, monitoring, control, risk assessment, and prevention of these contaminants in the environmental bodies are important subjects associated with public health. Thus, rapid, sensitive, selective, simple, and accurate analytical methods for the identification and determination of cyanotoxins are required. In this paper, the sampling methodologies and applications of solid phase-based sample preparation methods for the determination of cyanotoxins in environmental matrices are reviewed. The sample preparation techniques mainly include solid phase micro-extraction (SPME), solid phase extraction (SPE), and solid phase adsorption toxin tracking technology (SPATT). In addition, advantages and disadvantages and future prospects of these methods have been discussed.

Development and Validation of HPLC Method for Determination of Crocetin, a constituent of Saffron, in Human Serum Samples.

PubMed

Mohammadpour, Amir Hooshang; Ramezani, Mohammad; Tavakoli Anaraki, Nasim; Malaekeh-Nikouei, Bizhan; Amel Farzad, Sara; Hosseinzadeh, Hossein

2013-01-01

The present study reports the development and validation of a sensitive and rapid extraction method beside high performance liquid chromatographic method for the determination of crocetin in human serum. The HPLC method was carried out by using a C18 reversed-phase column and a mobile phase composed of methanol/water/acetic acid (85:14.5:0.5 v/v/v) at the flow rate of 0.8 ml/min. The UV detector was set at 423 nm and 13-cis retinoic acid was used as the internal standard. Serum samples were pretreated with solid-phase extraction using Bond Elut C18 (200mg) cartridges or with direct precipitation using acetonitrile. The calibration curves were linear over the range of 0.05-1.25 µg/ml for direct precipitation method and 0.5-5 µg/ml for solid-phase extraction. The mean recoveries of crocetin over a concentration range of 0.05-5 µg/ml serum for direct precipitation method and 0.5-5 µg/ml for solid-phase extraction were above 70 % and 60 %, respectively. The intraday coefficients of variation were 0.37- 2.6% for direct precipitation method and 0.64 - 5.43% for solid-phase extraction. The inter day coefficients of variation were 1.69 - 6.03% for direct precipitation method and 5.13-12.74% for solid-phase extraction, respectively. The lower limit of quantification for crocetin was 0.05 µg/ml for direct precipitation method and 0.5 µg/ml for solid-phase extraction. The validated direct precipitation method for HPLC satisfied all of the criteria that were necessary for a bioanalytical method and could reliably quantitate crocetin in human serum for future clinical pharmacokinetic study.

Development and Validation of HPLC Method for Determination of Crocetin, a constituent of Saffron, in Human Serum Samples

PubMed Central

Mohammadpour, Amir Hooshang; Ramezani, Mohammad; Tavakoli Anaraki, Nasim; Malaekeh-Nikouei, Bizhan; Amel Farzad, Sara; Hosseinzadeh, Hossein

2013-01-01

Objective(s): The present study reports the development and validation of a sensitive and rapid extraction method beside high performance liquid chromatographic method for the determination of crocetin in human serum. Materials and Methods: The HPLC method was carried out by using a C18 reversed-phase column and a mobile phase composed of methanol/water/acetic acid (85:14.5:0.5 v/v/v) at the flow rate of 0.8 ml/min. The UV detector was set at 423 nm and 13-cis retinoic acid was used as the internal standard. Serum samples were pretreated with solid-phase extraction using Bond Elut C18 (200mg) cartridges or with direct precipitation using acetonitrile. Results: The calibration curves were linear over the range of 0.05-1.25 µg/ml for direct precipitation method and 0.5-5 µg/ml for solid-phase extraction. The mean recoveries of crocetin over a concentration range of 0.05-5 µg/ml serum for direct precipitation method and 0.5-5 µg/ml for solid-phase extraction were above 70 % and 60 %, respectively. The intraday coefficients of variation were 0.37- 2.6% for direct precipitation method and 0.64 - 5.43% for solid-phase extraction. The inter day coefficients of variation were 1.69 – 6.03% for direct precipitation method and 5.13-12.74% for solid-phase extraction, respectively. The lower limit of quantification for crocetin was 0.05 µg/ml for direct precipitation method and 0.5 µg/ml for solid-phase extraction. Conclusion: The validated direct precipitation method for HPLC satisfied all of the criteria that were necessary for a bioanalytical method and could reliably quantitate crocetin in human serum for future clinical pharmacokinetic study. PMID:23638292

Multiplexed Colorimetric Solid-Phase Extraction

NASA Technical Reports Server (NTRS)

Gazda, Daniel B.; Fritz, James S.; Porter, Marc D.

2009-01-01

Multiplexed colorimetric solid-phase extraction (MC-SPE) is an extension of colorimetric solid-phase extraction (C-SPE) an analytical platform that combines colorimetric reagents, solid phase extraction, and diffuse reflectance spectroscopy to quantify trace analytes in water. In CSPE, analytes are extracted and complexed on the surface of an extraction membrane impregnated with a colorimetric reagent. The analytes are then quantified directly on the membrane surface using a handheld diffuse reflectance spectrophotometer. Importantly, the use of solid-phase extraction membranes as the matrix for impregnation of the colorimetric reagents creates a concentration factor that enables the detection of low concentrations of analytes in small sample volumes. In extending C-SPE to a multiplexed format, a filter holder that incorporates discrete analysis channels and a jig that facilitates the concurrent operation of multiple sample syringes have been designed, enabling the simultaneous determination of multiple analytes. Separate, single analyte membranes, placed in a readout cartridge create unique, analyte-specific addresses at the exit of each channel. Following sample exposure, the diffuse reflectance spectrum of each address is collected serially and the Kubelka-Munk function is used to quantify each water quality parameter via calibration curves. In a demonstration, MC-SPE was used to measure the pH of a sample and quantitate Ag(I) and Ni(II).

[Determination of patulin in fruits and jam by solid phase extraction-ultra performance liquid chromatography].

PubMed

Lü, Weichao; Shen, Shuchang; Wang, Chao

2017-11-08

With magnesium silicate, silica gel, diatomite and calcium sulfate as raw materials, a new solid phase extraction column was prepared through a series of processes of grinding to ethanol homogenate, drying and packing into polypropylene tube. The sample was hydrolyzed by pectinase, extracted by acetonitrile and purified by solid phase extraction. The target compounds were separated on a C18 column (100 mm×2.1 mm, 1.8 μm), using 0.8% (v/v) tetrahydrofuran solution as mobile phase with a flow rate of 0.5 mL/min. The detection wavelength was 276 nm. The effect of pectinase on extraction yield and purification effect of solid-phase extraction column were investigated. The optimum chromatographic conditions were selected. There was a good linear relationship between the peak heights and the mass concentrations of patulin in the range of 0.1 to 10 mg/L with the correlation coefficient ( R 2 ) of 1. The limit of detection for this method was 10.22 μg/kg. The spiked recoveries of samples were 86.58%-94.84% with the relative standard deviations (RSDs) of 1.45%-2.28%. The results indicated that the self-made solid phase extraction column had a good purification efficiency, and the UPLC had a high separation efficiency. The method is simple, accurate and of great significance for the quality and safety control of fruit products.

Simultaneous determination of 30 hormones illegally added to anti-ageing functional foods using UPLC-MS/MS coupled with SPE clean-up.

PubMed

He, Xiaoqin; Xi, Cunxian; Tang, Bobin; Wang, Guomin; Chen, Dongdong; Peng, Tao; Mu, Zhaode

2014-01-01

A novel analytical method employing solid-phase extraction (SPE) coupled with ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the simultaneous determination of 30 hormones in anti-ageing functional foods (capsules, powders and tablets). The analytes were extracted with acetic acid-acetonitrile (1-99 v/v), methanol and acetone, respectively. The extract was purified using a combined column, followed by analyte detection with electrospray ionisation in positive- or negative-ion modes. The results indicated that the 30 compounds had good linear correlations in the range of 1-1000 μg kg⁻¹, and the correlation coefficients were above 0.99. The limits of detection (LOD) and limits of quantification (LOQ) were 0.03-2 and 0.1-5 μg kg⁻¹, respectively. The average recovery of 30 compounds at the three spiked levels varied from 74.7% to 124.1%, and the relative standard deviation (RSD) was 2.4-15.0%. This method was applied to the analysis of hormones in 14 real samples of which seven hormones (such as estrone, dienestrol) were detected in four samples, but the remainder of the hormones were not detected. The developed method is sensitive, efficient, reliable and applicable to real samples.

Determination of quinolones and fluoroquinolones, tetracyclines and sulfonamides in bovine, swine and poultry liver using LC-MS/MS.

PubMed

Martins, Magda Targa; Barreto, Fabiano; Hoff, Rodrigo Barcelos; Jank, Louise; Arsand, Juliana Bazzan; Feijó, Tiago Correa; Schapoval, Elfrides Eva Scherman

2015-01-01

Antibacterials are widely used in veterinary medicine. Residues of these drugs can remain in food of animal origin, including bovine liver. This paper describes a fast and simple analytical method for the determination of quinolones and fluoroquinolones, tetracyclines and sulfonamides in bovine liver samples. Deuterated enrofloxacin, sulfapyridine and demeclocycline were used as internal standards. The homogenised liver samples were extracted with acidified acetonitrile. Steps of non-solid-phase extraction (SPE) clean-up and concentration were used in the presented method. The final extracts were analysed by sensitive and selective detection of all components in a single run using LC-MS/MS. Acceptable recoveries between 66% and 110% were obtained. Good linearity (r(2)) above 0.96, considering three different days, for all drugs was achieved in concentrations ranging from 0.0 to 2.0 × the maximum residue limit (MRL). Intraday precision with coefficient of variation (CV%) (n = 6) lower than 14.7% and inter-day precision lower than 18.8% in agreement with European Commission Decision 2002/657/EC were obtained in concentrations ranging from 0.5 to 1.5 MRL. Accuracy was between 86% and 110%. Limits of detection and quantitation, as well as decision limit (CCα) and detection capability (CCβ), were also evaluated.

Hollow fibre liquid phase micro-extraction by facilitated anionic exchange for the determination of flavonoids in faba beans (Vicia faba L.).

PubMed

Chaieb, Nadia; López-Mesas, Montserrat; Luis González, Johannes; Mars, Messaoud; Valiente, Manuel

2015-01-01

Flavonoids are polyphenolic compounds found ubiquitously in foods of plant origin. They are commonly extracted from plant materials with ethanol, methanol, water, their combination or even with acidified extracting solutions. The disadvantages of these methods are the use of high quantity of organic solvent, the possible loss of analytes in the different steps and the laborious process of the techniques. In addition, the complexity of the phenolic mixtures present in plant materials requires a preliminary clean-up and fractionation of the crude extracts. To develop a hollow fibre liquid phase micro-extraction (HF-LPME) method for a one step clean-up and pre-concentration of flavonoids. Two flavonoids (catechin and rutin) has been extracted by HF-LPME and analysed by HPLC. The related driving force for the liquid membrane has been studied by means of facilitated and non-facilitated transport. Different ionic and non-ionic water insoluble compounds [trioctylamine (TOA), tributyl phosphate (TBP), trioctylphosphine oxide (TOPO) and methyltrioctylammonium chloride (aliquat 336)] were used as carriers. The liquid membrane was constituted by a solution of n-decanol in the presence or absence of carriers. Maximum enrichment factors were obtained with n-decanol/aliquat 336 (20%) as organic liquid membrane, sodium hydroxide (NaOH) (0.1 M) as donor solution, sodium chloride (NaCl) (2 M) as acceptor solution and 3 h as extraction time. Under these conditions, good results for validation parameters were obtained [for linearity, limit of detection (LOD), limit of quantitation (LOQ) and repeatability]. The developed method is simple, effective and has been successfully applied to determine catechin and rutin in ethanolic extracts of faba beans. Copyright © 2015 John Wiley & Sons, Ltd.

Ultra-trace level determination of diquat and paraquat residues in surface and drinking water using ion-pair liquid chromatography with tandem mass spectrometry: a comparison of direct injection and solid-phase extraction methods.

PubMed

Oh, Jin-Aa; Lee, Jun-Bae; Lee, Soo-Hyung; Shin, Ho-Sang

2014-10-01

Direct injection and solid-phase extraction methods for the determination of diquat and paraquat in surface and drinking water were developed using liquid chromatography with tandem mass spectrometry. The signal intensities of analytes based on six ion-pairing reagents were compared with each other, and 12.5 mM nonafluoropentanoic acid was selected as the best suited amongst them. A clean-up method was developed using Oasis hydrophilic-lipophilic balance; this was compared to the direct injection method, with respect to limits of detection, interference, precision, and accuracy. Limits of quantification of diquat and paraquat were 0.03 and 0.01 μg/L using the direct injection method, and 0.002 and 0.001 μg/L using the hydrophilic-lipophilic balance method. When the hydrophilic-lipophilic balance method was used to analyze target compounds in 114 surface water and 30 drinking water samples, paraquat and diquat were detected within a concentration range of 0.001-0.12 and 0.002-0.038 μg/L in surface water, respectively. When the direct injection method was used to analyze target compounds in the same samples, the detected concentrations of paraquat and diquat were within 25% in samples being >0.015 μg/L using the hydrophilic-lipophilic balance method. The liquid chromatography with tandem mass spectrometry method using direct injection can thus be used for routine monitoring of paraquat and diquat in surface and drinking water. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bioassay-guided supercritical fluid extraction of cyclooxygenase-2 inhibiting substances in Plantago major L.

PubMed

Stenholm, A; Göransson, U; Bohlin, L

2013-02-01

Selective extraction of plant materials is advantageous for obtaining extracts enriched with desired constituents, thereby reducing the need for subsequent chromatography purification. Such compounds include three cyclooxygenase-2 (COX-2) inhibitory substances in Plantago major L. targeted in this investigation: α-linolenic acid (α-LNA) (18:3 ω-3) and the triterpenic acids ursolic acid and oleanolic acid. To investigate the scope for tuning the selectivity of supercritical fluid extraction (SFE) using bioassay guidance, and Soxhlet extraction with dichloromethane as solvent as a reference technique, to optimise yields of these substances. Extraction parameters were varied to optimise extracts' COX-2/COX-1 inhibitory effect ratios. The crude extracts were purified initially using a solid phase extraction (SPE) clean-up procedure and the target compounds were identified with GC-MS, LC-ESI-MS and LC-ESI-MS² using GC-FID for quantification. α-LNA was preferentially extracted in dynamic mode using unmodified carbon dioxide at 40°C and 172 bar, at a 0.04% (w/w) yield with a COX-2/COX-1 inhibitory effect ratio of 1.5. Ursolic and oleanolic acids were dynamically extracted at 0.25% and 0.06% yields, respectively, with no traces of (α-LNA) and a COX-2/COX-1-inhibitory effect ratio of 1.1 using 10% (v/v) ethanol as polar modifier at 75°C and 483 bar. The Soxhlet extracts had ursolic acid, oleanolic acid and αLNA yields up to 1.36%, 0.34% and 0.15%, respectively, with a COX-2/COX-1 inhibitory effect ratio of 1.2. The target substances can be extracted selectively by bioassay guided optimisation of SFE conditions. Copyright © 2012 John Wiley & Sons, Ltd.

Aptamer functionalized magnetic nanoparticles for effective extraction of ultratrace amounts of aflatoxin M1 prior its determination by HPLC.

PubMed

Khodadadi, Mohammad; Malekpour, Akbar; Mehrgardi, Masoud A

2018-06-09

Aptamers, due to the inherently high selectivity towards target analytes, are promising candidate for surface modification of the nanoparticles. Therefore, aptamer-functionalized magnetic nanoparticles (AMNPs) was prepared and used to develop a magnetic solid-phase extraction procedure for clean-up of milk and dairy products samples before measuring the aflatoxin M1 (AFM1) contents by the high-performance liquid chromatography. The prepared sorbent was characterized by different instrumental methods such as FT-IR, FESEM, TEM, EDX and AGFM. The AMNPs was used in extraction and pre-concentration of ultratrace amounts AFM1 from local milk samples. The amount of sorbent, elution volume, extraction time, and salt addition were optimized. Based on the results, calibration plot is linear over the 0.3 to 1 ng·L -1 and 5 to 50 ng·L -1 AFM1 concentration ranges. The limits of detection of the developed method were obtained 0.2 ng·L -1 which is the smallest value that has been reported up to now. The results show that this new superior sorbent has a large potential to simplify the complex matrix of the samples and can used for detection, preconcentration and accurate determination of ultratrace amounts of the AFM1 from milk and dairy products. Copyright © 2018 Elsevier B.V. All rights reserved.

Development and Validation of a Multiresidue Method for the Determination of Pesticides in Dry Samples (Rice and Wheat Flour) Using Liquid Chromatography/Triple Quadrupole Tandem Mass Spectrometry.

PubMed

Grande-Martínez, Ángel; Arrebola, Francisco Javier; Moreno, Laura Díaz; Vidal, José Luis Martínez; Frenich, Antonia Garrido

2015-01-01

A rapid and sensitive multiresidue method was developed and validated for the determination of around 100 pesticides in dry samples (rice and wheat flour) by ultra-performance LC coupled to a triple quadrupole mass analyzer working in tandem mode (UPLC/QqQ-MS/MS). The sample preparation step was optimized for both matrixes. Pesticides were extracted from rice samples using aqueous ethyl acetate, while aqueous acetonitrile extraction [modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method] was used for wheat flour matrixes. In both cases the extracts were then cleaned up by dispersive solid phase extraction with MgSO4 and primary secondary amine+C18 sorbents. A further cleanup step with Florisil was necessary to remove fat in wheat flour. The method was validated at two concentration levels (3.6 and 40 μg/kg for most compounds), obtaining recoveries ranging from 70 to 120%, intraday and interday precision values≤20% expressed as RSDs, and expanded uncertainty values≤50%. The LOQ values ranged between 3.6 and 20 μg/kg, although it was set at 3.6 μg/kg for the majority of the pesticides. The method was applied to the analysis of 20 real samples, and no pesticides were detected.

Evaluation of two methods to determine glyphosate and AMPA in soils of Argentina

NASA Astrophysics Data System (ADS)

De Geronimo, Eduardo; Lorenzon, Claudio; Iwasita, Barbara; Faggioli, Valeria; Aparicio, Virginia; Costa, Jose Luis

2017-04-01

Argentine agricultural production is fundamentally based on a technological package combining no-tillage and the dependence of glyphosate applications to control weeds in transgenic crops (soybean, maize and cotton). Therefore, glyphosate is the most employed herbicide in the country, where 180 to 200 million liters are applied every year. Due to its widespread use, it is important to assess its impact on the environment and, therefore, reliable analytical methods are mandatory. Glyphosate molecule exhibits unique physical and chemical characteristics which difficult its quantification, especially in soils with high organic matter content, such as the central eastern Argentine soils, where strong interferences are normally observed. The objective of this work was to compare two methods for extraction and quantification of glyphosate and AMPA in samples of 8 representative soils of Argentina. The first analytical method (method 1) was based on the use of phosphate buffer as extracting solution and dichloromethane to minimize matrix organic content. In the second method (method 2), potassium hydroxide was used to extract the analytes followed by a clean-up step using solid phase extraction (SPE) to minimize strong interferences. Sensitivity, recoveries, matrix effects and robustness were evaluated. Both methodologies involved a derivatization with 9-fluorenyl-methyl-chloroformate (FMOC) in borate buffer and detection based on ultra-high-pressure liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). Recoveries obtained from soil samples spiked at 0.1 and 1 mg kg-1 and were satisfactory in both methods (70% - 120%). However, there was a remarkable difference regarding the matrix effect, being the SPE clean-up step (method 2) insufficient to remove the interferences. Whereas the dilution and the clean-up with dichloromethane (method 1) were more effective minimizing the ionic suppression. Moreover, method 1 had fewer steps in the protocol of sample processing than method 2. This can be highly valuable in the routine lab work due to the reduction of potential undesired errors such as the loss of analyte or sample contamination. In addition, the substitution of SPE by another alternative involved a considerable reduction of analytical costs in method 1. We conclude that method 1 seemed to be simpler and cheaper than method 2, as well as reliable to quantify glyphosate in Argentinean soils. We hope that this experience can be useful to simplify the protocols of glyphosate quantification and contribute to the understanding of the fate of this herbicide in the environment.

Evaluation of various QuEChERS based methods for the analysis of herbicides and other commonly used pesticides in polished rice by LC-MS/MS.

PubMed

Pareja, Lucía; Cesio, Verónica; Heinzen, Horacio; Fernández-Alba, Amadeo R

2011-02-15

Four different extraction and clean-up protocols based on the QuEChERS method were compared for the development of an optimized sample preparation procedure for the multiresidue analysis of 16 commonly applied herbicides in rice crops using LC-QqQ/MS. Additionally the methods were evaluated for the analysis of 26 insecticides and fungicides currently used in rice crops. The methods comprise, in general, the hydratation of the sample with water followed by the extraction with acetonitrile, phase separation with the addition of different salts and finally a clean-up step with various sorbents. Matrix effects were evaluated for the 4 studied methods using LC-QqQ/MS. Additionally LC-TOF/MS was used to compare the co-extractants obtained with the four assayed methodologies. Thirty-six pesticides presented good performance with recoveries in the range 70-120% and relative standard deviations below 20% using 7.5 g of milled polished rice and the buffered acetate QuEChERS method without clean-up at both fortification levels: 10 and 300 μg kg(-1). The other six pesticides presented low recovery rates, nevertheless all these analytes could be analyzed with at least one of the other three studied procedures. Copyright © 2010. Published by Elsevier B.V.

Simultaneous determination of 24 personal care products in fish muscle and liver tissues using QuEChERS extraction coupled with ultra pressure liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometer analyses.

PubMed

Yao, Li; Zhao, Jian-Liang; Liu, You-Sheng; Yang, Yuan-Yuan; Liu, Wang-Rong; Ying, Guang-Guo

2016-11-01

A sensitive and selective quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction combined with dispersive solid-phase extraction (d-SPE) cleanup method was developed to simultaneously extract a wide range of personal care products (16 biocides, 4 synthetic musks, and 4 benzotriazoles) in fish muscle and liver tissues. In order to get satisfactory recoveries, different extraction parameters were optimized, including extraction salts and d-SPE materials, extraction solvents and acetic acid contents in organic phase, and the ratios of solvent and water. Ultra pressure liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry were used to analyze the target compounds in the extracts. Among the 24 personal care products, the recoveries in the range of 70-120 % were obtained for 20, 19, and 12 analytes in fish muscle at the spiking concentrations of 10, 5, and 1 ng/g ww, respectively, and for 13, 12, and 11 analytes in liver at the spiking concentrations of 40, 20, and 4 ng/g ww, respectively. Method quantification limits (MQLs) of all analytes were 0.02-2.12 ng/g ww for fish muscle and 0.22-12.2 ng/g ww for fish liver tissues. The method was successfully applied to wild fish samples collected from Dongjiang River, south China. Twenty-one and 17 of the analytes were found in fish muscle and liver samples, respectively, in at least one site of the river with the concentrations between below MQLs and 119 ng/g ww, respectively. Graphical abstract Achieved satisfactory recoveries, high precision, and low method quantification limits (MQLs) for PCPs in wild fish tissues by QuEChERS procedure optimization combined with UPLC-MS/MS and GC-MS analyses.

Feasibility and application of an HPLC/UVD to determine dinotefuran and its shorter wavelength metabolites residues in melon with tandem mass confirmation.

PubMed

Rahman, Md Musfiqur; Park, Jong-Hyouk; Abd El-Aty, A M; Choi, Jeong-Heui; Yang, Angel; Park, Ki Hun; Nashir Uddin Al Mahmud, Md; Im, Geon-Jae; Shim, Jae-Han

2013-01-15

A new analytical method was developed for dinotefuran and its metabolites, MNG, UF, and DN, in melon using high-performance liquid chromatography (HPLC) coupled with an ultraviolet detector (UVD). Due to shorter wavelength, lower sensitivity to UV detection, and high water miscibility of some metabolites, QuEChERs acetate-buffered version was modified for extraction and purification. Mobile phases with different ion pairing or ionisation agents were tested in different reverse phase columns, and ammonium bicarbonate buffer was found as the best choice to increase the sensitivity of target analytes to the UV detector. After failure of dispersive SPE clean-up with primary secondary amine, different solid phase extraction cartridges (SPE) were used to check the protecting capability of analytes against matrix interference. Finally, samples were extracted with a simple and rapid method using acetonitrile and salts, and purified through C(18)SPE. The method was validated at two spiking levels (three replicates for each) in the matrix. Good recoveries were observed for all of the analytes and ranged between 70.6% and 93.5%, with relative standard deviations of less than 10%. Calibration curves were linear over the calibration ranges for all the analytes with r(2)≥ 0.998. Limits of detection ranged from 0.02 to 0.05 mg kg(-1), whereas limits of quantitation ranged from 0.06 to 0.16 mg kg(-1) for dinotefuran and its metabolites. The method was successfully applied to real samples, where dinotefuran and UF residues were found in the field-incurred melon samples. Residues were confirmed via LC-tandem mass spectrometry (LC-MS/MS) in positive-ion electrospray ionisation (ESI(+)) mode. Copyright © 2012 Elsevier Ltd. All rights reserved.

SEQUENTIAL EXTRACTIONS FOR PARTITIONING OF ARSENIC ON HYDROUS IRON OXIDES AND IRON SULFIDES

EPA Science Inventory

The objective of this study was to use model solids to test solutions designed to extract arsenic from relatively labile solid phase fractions. The use of sequential extractions provides analytical constraints on the identification of mineral phases that control arsenic mobility...

Hypercrosslinked particles for the extraction of sweeteners using dispersive solid-phase extraction from environmental samples.

PubMed

Lakade, Sameer S; Zhou, Qing; Li, Aimin; Borrull, Francesc; Fontanals, Núria; Marcé, Rosa M

2018-04-01

This work presents a new extraction material, namely, Q-100, based on hypercrosslinked magnetic particles, which was tested in dispersive solid-phase extraction for a group of sweeteners from environmental samples. The hypercrosslinked Q-100 magnetic particles had the advantage of suitable pore size distribution and high surface area, and showed good retention behavior toward sweeteners. Different dispersive solid-phase extraction parameters such as amount of magnetic particles or extraction time were optimized. Under optimum conditions, Q-100 showed suitable apparent recovery, ranging in the case of river water sample from 21 to 88% for all the sweeteners, except for alitame (12%). The validated method based on dispersive solid-phase extraction using Q-100 followed by liquid chromatography with tandem mass spectrometry provided good linearity and limits of quantification between 0.01 and 0.1 μg/L. The method was applied to analyze samples from river water and effluent wastewater, and four sweeteners (acesulfame, saccharin, cyclamate, and sucralose) were found in both types of sample. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Microwave assisted solid phase extraction for separation preconcentration sulfamethoxazole in wastewater using tyre based activated carbon as solid phase material prior to spectrophotometric determination

NASA Astrophysics Data System (ADS)

Mogolodi Dimpe, K.; Mpupa, Anele; Nomngongo, Philiswa N.

2018-01-01

This work was chiefly encouraged by the continuous consumption of antibiotics which eventually pose harmful effects on animals and human beings when present in water systems. In this study, the activated carbon (AC) was used as a solid phase material for the removal of sulfamethoxazole (SMX) in wastewater samples. The microwave assisted solid phase extraction (MASPE) as a sample extraction method was employed to better extract SMX in water samples and finally the analysis of SMX was done by the UV-Vis spectrophotometer. The microwave assisted solid phase extraction method was optimized using a two-level fractional factorial design by evaluating parameters such as pH, mass of adsorbent (MA), extraction time (ET), eluent ratio (ER) and microwave power (MP). Under optimized conditions, the limit of detection (LOD) and limit of quantification (LOQ) were 0.5 μg L- 1 and 1.7 μg L- 1, respectively, and intraday and interday precision expressed in terms of relative standard deviation were > 6%.The maximum adsorption capacity was 138 mg g- 1 for SMX and the adsorbent could be reused eight times. Lastly, the MASPE method was applied for the removal of SMX in wastewater samples collected from a domestic wastewater treatment plant (WWTP) and river water.

Assessing the Selectivity of Extractant Solutions for Recovering Labile Arsenic Associated with Iron (Hydr)oxides and Sulfides in Sediments

EPA Science Inventory

Sequential extractions can provide analytical constraints on the identification of mineral phases that control arsenic speciation in sediments. Model solids were used in this study to evaluate different solutions designed to extract arsenic from relatively labile solid phases. ...

Determination of selected non-authorized insecticides in peppers by liquid chromatography time-of-flight mass spectrometry and tandem mass spectrometry.

PubMed

Mezcua, Milagros; Ferrer, Carmen; García-Reyes, Juan F; Martínez-Bueno, María Jesús; Albarracín, Micaela; Claret, María; Fernández-Alba, Amadeo R

2008-05-01

In this work, two analytical methods based on liquid chromatography coupled to electrospray time-of-flight mass spectrometry (LC/ESI-TOFMS) and tandem mass spectrometry (LC/ESI-MS/MS) are described for the identification, confirmation and quantitation of three insecticides non-authorized in the European Union (nitenpyram, isocarbophos and isofenphos-methyl) but detected in recent monitoring programmes in pepper samples. The proposed methodologies involved a sample extraction procedure using liquid-liquid partition with acetonitrile followed by a cleanup step based on dispersive solid-phase extraction. Recovery studies performed on peppers spiked at different fortification levels (10 and 50 microg kg(-1)) yielded average recoveries in the range 76-100% with relative standard deviation (RSD) (%) values below 10%. Identification, confirmation and quantitation were carried out by LC/TOFMS and LC/MS/MS using a hybrid triple quadrupole linear ion trap (QqLIT) instrument in multiple-reaction monitoring (MRM) mode. The obtained limits of quantitation (LOQs) were in the range 0.1-5 microg kg(-1), depending on each individual technique. Finally, the proposed methods were successfully applied to the analysis of suspected pepper samples. Copyright (c) 2008 John Wiley & Sons, Ltd.

Preparation of l-phenylalanine-imprinted solid-phase extraction sorbent by Pickering emulsion polymerization and the selective enrichment of l-phenylalanine from human urine.

PubMed

Li, Ji; Hu, Xiaoling; Guan, Ping; Zhang, Xiaoyan; Qian, Liwei; Zhang, Nan; Du, Chunbao; Song, Renyuan

2016-05-01

A novel l-phenylalanine molecularly imprinted solid-phase extraction sorbent was synthesized by the combination of Pickering emulsion polymerization and ion-pair dummy template imprinting. Compared to other polymerization methods, the molecularly imprinted polymers thus prepared exhibit a high specific surface, large pore diameter, and appropriate particle size. The key parameters for solid-phase extraction were optimized, and the result indicated that the molecularly imprinted polymer thus prepared exhibits a good recovery of 98.9% for l-phenylalanine. Under the optimized conditions of the procedure, an analytical method for l-phenylalanine was well established. By comparing the performance of the molecularly imprinted polymer and a commercial reverse-phase silica gel, the obtained molecularly imprinted polymer as an solid-phase extraction sorbent is more suitable, exhibiting high precision (relative standard deviation 3.2%, n = 4) and a low limit of detection (60.0 ± 1.9 nmol·L(-1) ) for the isolation of l-phenylalanine. Based on these results, the combination of the Pickering emulsion polymerization and ion-pair dummy template imprinting is effective for preparing selective solid-phase extraction sorbents for the separation of amino acids and organic acids from complex biological samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Molecularly imprinted polymer/cryogel composites for solid-phase extraction of bisphenol A from river water and wine.

PubMed

Baggiani, Claudio; Baravalle, Patrizia; Giovannoli, Cristina; Anfossi, Laura; Giraudi, Gianfranco

2010-05-01

Superporous monolithic hydrogels (cryogel monoliths) are elastic, sponge-like materials that can be prepared in an aqueous medium through a cryotropic gelation technique. These monoliths show interesting properties for the development of high-throughput solid-phase extraction supports to treat large volumes of aqueous samples. In this work, a cryogel-supported molecularly imprinted solid-phase extraction approach for the endocrine disruptor bisphenol A (BPA) from river water and wine samples is presented. An imprinted polymer with molecular recognition properties for BPA was prepared in acetonitrile by thermal polymerization of a mixture of 4,4'-dihydroxy-2,2-diphenyl-1,1,1,3,3,3-trifluoropropane as a mimic template of BPA, 4-vinylpyridine and trimethylolpropane trimethacrylate in a molar ratio of 1 + 6 + 6. Fine imprinted particles (<10 microm) were embedded in a poly-acrylamide-co-N,N'-methylenbisacrylamide cryogel obtained by ammonium persulfate-induced cryopolymerization at -18 degrees C. The resulting monolithic gel was evaluated for its use as a sorbent support in an off-line solid-phase extraction approach to recover BPA from dilute aqueous samples with minimum pre-loading work-up. The optimized extraction protocol resulted in a reliable MISPE method suitable to selectively extract and preconcentrate BPA from river water and red wine samples, demonstrating the practical feasibility of cryogel-trapped imprinted polymers as solid-phase extraction materials.

Fast and effective low-temperature freezing extraction technique to determine organotin compounds in edible vegetable oil.

PubMed

Liu, Yingxia; Ma, Yaqian; Wan, Yiqun; Guo, Lan; Wan, Xiaofen

2016-06-01

Most organotin compounds that have been widely used in food packaging materials and production process show serious toxicity effects to human health. In this study, a simple and low-cost method based on high-performance liquid chromatography with inductively coupled plasma mass spectrometry for the simultaneous determination of four organotins in edible vegetable oil samples was developed. Four organotins including dibutyltin dichloride, tributyltin chloride, diphenyltin dichloride, and triphenyltin chloride were simultaneously extracted with methanol using the low-temperature precipitation process. After being concentrated, the extracts were purified by matrix solid-phase dispersion using graphitized carbon black. The experimental parameters such as extraction solvent and clean-up material were optimized. To evaluate the accuracy of the new method, the recoveries were investigated. In addition, a liquid chromatography with tandem mass spectrometry method was also proposed for comparison. The procedures of extracting and purifying samples for the analysis were simple and easy to perform batch operations, also showed good efficiency with lower relative standard deviation. The limits of detection of the four organotins were 0.28-0.59 μg/L, and the limits of quantification of the four organotins were 0.93-1.8 μg/L, respectively. The proposed method was successfully applied to the simultaneous analysis of the four organotins in edible vegetable oil. Some analytes were detected at the level of 2.5-28.8 μg/kg. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Simple and Fast Extraction Method for the Determination of Multiclass Antibiotics in Eggs Using LC-MS/MS.

PubMed

Wang, Kun; Lin, Kunde; Huang, Xinwen; Chen, Meng

2017-06-21

The purpose of this study was to develop and validate a simple, fast, and specific extraction method for the analysis of 64 antibiotics from nine classes (including sulfonamides, quinolones, tetracyclines, macrolides, lincosamide, nitrofurans, β-lactams, nitromidazoles, and cloramphenicols) in chicken eggs. Briefly, egg samples were simply extracted with a mixture of acetonitrile-water (90:10, v/v) and 0.1 mol·L -1 Na 2 EDTA solution assisted with ultrasonic. The extract was centrifuged, condensed, and directly analyzed on a liquid chromatography coupled to tandem mass spectrometry. Compared with conventional cleanup methods (passing through solid phase extract cartridges), the established method demonstrated comparable efficiencies in eliminating matrix effects and higher or equivalent recoveries for most of the target compounds. Typical validation parameters including specificity, linearity, matrix effect, limits of detection (LODs) and quantification (LOQs), the decision limit, detection capability, trueness, and precision were evaluated. The recoveries of target compounds ranged from 70.8% to 116.1% at three spiking levels (5, 20, and 50 μg·kg -1 ), with relative standard deviations less than 14%. LODs and LOQs were in the ranges of 0.005-2.00 μg·kg -1 and 0.015-6.00 μg·kg -1 for all of the antibiotics, respectively. A total of five antibiotics were successfully detected in 22 commercial eggs from local markets. This work suggests that the method is suitable for the analysis of multiclass antibiotics in eggs.

Determination of selected neurotoxic insecticides in small amounts of animal tissue utilizing a newly constructed mini-extractor.

PubMed

Seifertová, Marta; Čechová, Eliška; Llansola, Marta; Felipo, Vicente; Vykoukalová, Martina; Kočan, Anton

2017-10-01

We developed a simple analytical method for the simultaneous determination of representatives of various groups of neurotoxic insecticides (carbaryl, chlorpyrifos, cypermethrin, and α-endosulfan and β-endosulfan and their metabolite endosulfan sulfate) in limited amounts of animal tissues containing different amounts of lipids. Selected tissues (rodent fat, liver, and brain) were extracted in a special in-house-designed mini-extractor constructed on the basis of the Soxhlet and Twisselmann extractors. A dried tissue sample placed in a small cartridge was extracted, while the nascent extract was simultaneously filtered through a layer of sodium sulfate. The extraction was followed by combined clean-up, including gel permeation chromatography (in case of high lipid content), ultrasonication, and solid-phase extraction chromatography using C 18 on silica and aluminum oxide. Gas chromatography coupled with high-resolution mass spectrometry was used for analyte separation, detection, and quantification. Average recoveries for individual insecticides ranged from 82 to 111%. Expanded measurement uncertainties were generally lower than 35%. The developed method was successfully applied to rat tissue samples obtained from an animal model dealing with insecticide exposure during brain development. This method may also be applied to the analytical treatment of small amounts of various types of animal and human tissue samples. A significant advantage achieved using this method is high sample throughput due to the simultaneous treatment of many samples. Graphical abstract Optimized workflow for the determination of selected insecticides in small amounts of animal tissue including newly developed mini-extractor.

Determination of household and industrial chemicals, personal care products and hormones in leafy and root vegetables by liquid chromatography-tandem mass spectrometry.

PubMed

Aparicio, Irene; Martín, Julia; Abril, Concepción; Santos, Juan Luis; Alonso, Esteban

2018-01-19

A multiresidue method has been developed for the determination of emerging pollutants in leafy and root vegetables. Selected compounds were 6 perfluoroalkyl compounds (5 perfluorocarboxylic acids and perfluorooctanesulfonic acid), 3 non-ionic surfactants (nonylphenol and nonylphenolethoxylates), 8 anionic surfactants (4 alkylsulfates and 4 linear alkylbenzene sulfonates), 4 preservatives (parabens), 2 biocides (triclosan and triclocarban), 2 plasticizers (bisphenol A and di-(2-ethylhexyl)phthalate), 6 UV-filters (benzophenones) and 4 hormones. The method is based on ultrasound-assisted extraction, clean-up by dispersive solid-phase extraction (d-SPE) and liquid chromatography-tandem mass spectrometry analysis. Due to the diversity of the physico-chemical properties of the target compounds, and to better evaluate the influence of sample treatment variables in extraction efficiencies, Box-Behnken design was applied to optimize extraction solvent volume, number of extraction cycles and d-SPE sorbent amount. Linearity (R 2 ) higher than 0.992, accuracy (expressed as relative recoveries) in the range from 81 to 126%, precision (expressed as relative standard deviation) lower than 19% and limits of detection between 0.025 and 12.5ngg -1 dry weight were achieved. The method was applied to leafy vegetables (lettuce, spinach and chard) and root vegetables (carrot, turnip and potato) from a local market. The highest concentrations corresponded to the surfactants reaching levels up to 114ngg -1 (dry weight), in one of the lettuce samples analyzed. Copyright © 2017 Elsevier B.V. All rights reserved.

Simultaneous determination of phenolic compounds in Equisetum palustre L. by ultra high performance liquid chromatography with tandem mass spectrometry combined with matrix solid-phase dispersion extraction.

PubMed

Wei, Zuofu; Pan, Youzhi; Li, Lu; Huang, Yuyang; Qi, Xiaolin; Luo, Meng; Zu, Yuangang; Fu, Yujie

2014-11-01

A method based on matrix solid-phase dispersion extraction followed by ultra high performance liquid chromatography with tandem mass spectrometry is presented for the extraction and determination of phenolic compounds in Equisetum palustre. This method combines the high efficiency of matrix solid-phase dispersion extraction and the rapidity, sensitivity, and accuracy of ultra high performance liquid chromatography with tandem mass spectrometry. The influential parameters of the matrix solid-phase dispersion extraction were investigated and optimized. The optimized conditions were as follows: silica gel was selected as dispersing sorbent, the ratio of silica gel to sample was selected to be 2:1 (400/200 mg), and 8 mL of 80% methanol was used as elution solvent. Furthermore, a fast and sensitive ultra high performance liquid chromatography with tandem mass spectrometry method was developed for the determination of nine phenolic compounds in E. palustre. This method was carried out within <6 min, and exhibited satisfactory linearity, precision, and recovery. Compared with ultrasound-assisted extraction, the proposed matrix solid-phase dispersion procedure possessed higher extraction efficiency, and was more convenient and time saving with reduced requirements on sample and solvent amounts. All these results suggest that the developed method represents an excellent alternative for the extraction and determination of active components in plant matrices. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Silica Modified with Polyaniline as a Potential Sorbent for Matrix Solid Phase Dispersion (MSPD) and Dispersive Solid Phase Extraction (d-SPE) of Plant Samples

PubMed Central

Sowa, Ireneusz; Wójciak-Kosior, Magdalena; Strzemski, Maciej; Sawicki, Jan; Staniak, Michał; Dresler, Sławomir; Szwerc, Wojciech; Mołdoch, Jarosław; Latalski, Michał

2018-01-01

Polyaniline (PANI) is one of the best known conductive polymers with multiple applications. Recently, it was also used in separation techniques, mostly as a component of composites for solid-phase microextraction (SPME). In the present paper, sorbent obtained by in situ polymerization of aniline directly on silica gel particles (Si-PANI) was used for dispersive solid phase extraction (d-SPE) and matrix solid–phase extraction (MSPD). The efficiency of both techniques was evaluated with the use of high performance liquid chromatography with diode array detection (HPLC-DAD) quantitative analysis. The quality of the sorbent was verified by Raman spectroscopy and microscopy combined with automated procedure using computer image analysis. For extraction experiments, triterpenes were chosen as model compounds. The optimal conditions were as follows: protonated Si-PANI impregnated with water, 160/1 sorbent/analyte ratio, 3 min of extraction time, 4 min of desorption time and methanolic solution of ammonia for elution of analytes. The proposed procedure was successfully used for pretreatment of plant samples. PMID:29565297

Validation of an Analytical Method for the Determination of Pesticide Residues in Vine Leaves by GC-MS/MS.

PubMed

Maestroni, Britt; Abu Alnaser, Amer; Ghanem, Iyad; Islam, Marivil; Cesio, Veronica; Heinzen, Horacio; Kelly, Simon; Cannavan, Andrew

2018-06-27

A modified and miniaturized SweEt/QuEChERS method for pesticide residue analysis applied to vine leaves is presented. The deep-frozen plant material was cryogenically processed. A 2 g analytical portion was hydrated for 30 min and extracted with acidified ethyl acetate after buffering with NaHCO 3 and adding Na 2 SO 4 . A dispersive solid-phase (d-SPE) cleanup step with primary-secondary amine (PSA) was performed. The pesticide residues were determined using GC-MS/MS. The whole procedure was validated for 54-59 pesticides at 0.01, 0.02, 0.1, and 0.2 mg/kg in fresh vine leaves ( Vitis vinifera). The key method performance parameters investigated were specificity, linearity, trueness, within laboratory repeatability and reproducibility, limit of detection, limit of quantitation, and matrix effects. Recoveries for the 59 pesticides tested ranged from 60 to 110%, and the RSDs were lower than 20% for the majority of the pesticides studied.

Mycotoxin occurrence in commodities, feeds and feed ingredients sourced in the Middle East and Africa

PubMed Central

Rodrigues, I.; Handl, J.; Binder, E.M.

2011-01-01

Between February and October 2009, 324 grain, feed and feed commodity samples were sourced directly at animal farms or feed production sites in Middle East and Africa and tested for the presence of A- and B-trichothecenes, zearalenone, fumonisins, aflatoxins and ochratoxin A, or for selected groups of mycotoxins only. Samples were analyzed after clean-up by immunoaffinity or solid-phase extraction followed by HPLC with derivatization where appropriate and fluorescence, UV or mass spectrometric detection. The percentage of positive samples of B-trichothecenes ranged from 0 to 87% of tested samples. The prevalence of fumonisins in the different countries was >50% in most cases. Zearalenone was present in tested commodities from all countries except three. The presence of aflatoxin in analyzed samples varied from 0 to 94%. Ochratoxin A was present in 67% of samples in Sudan and in 100% of Nigerian samples. No A-trichothecenes were found in this survey. PMID:24786003

Natural occurrence of alternariol and alternariol monomethyl ether in soya beans.

PubMed

Oviedo, M S; Barros, G G; Chulze, S N; Ramirez, M L

2012-08-01

The natural occurrence of alternariol (AOH) and alternariol monomethyl ether (AME) in soya beans harvested in Argentina was evaluated. Both toxins were simultaneously detected by using HPLC analysis coupled with a solid phase extraction column clean-up. Characteristics of this in-house method such as accuracy, precision and detection and quantification limits were defined by means of recovery test with spiked soya bean samples. Out of 50 soya bean samples, 60% showed contamination with the mycotoxins analyzed; among them, 16% were only contaminated with AOH and 14% just with AME. Fifteen of the positive samples showed co-occurrence of both mycotoxins analyzed. AOH was detected in concentrations ranging from 25 to 211 ng/g, whereas AME was found in concentrations ranging from 62 to 1,153 ng/g. Although a limited number of samples were evaluated, this is the first report on the natural occurrence of Alternaria toxins in soya beans and is relevant from the point of view of animal public health.

Development of a computationally-designed polymeric adsorbent specific for mycotoxin patulin.

PubMed

Piletska, Elena V; Pink, Demi; Karim, Kal; Piletsky, Sergey A

2017-12-04

Patulin is a toxic compound which is found predominantly in apples affected by mould rot. Since apples and apple-containing products are a popular food for the elderly, children and babies, the monitoring of the toxin is crucial. This paper describes a development of a computationally-designed polymeric adsorbent for the solid-phase extraction of patulin, which provides an effective clean-up of the food samples and allows the detection and accurate quantification of patulin levels present in apple juice using conventional chromatography methods. The developed bespoke polymer demonstrates a quantitative binding towards the patulin present in undiluted apple juice. The polymer is inexpensive and easy to mass-produce. The contributing factors to the function of the adsorbent is a combination of acidic and basic functional monomers producing a zwitterionic complex in the solution that formed stronger binding complexes with the patulin molecule. The protocols described in this paper provide a blueprint for the development of polymeric adsorbents for other toxins or different food matrices.

Identification and quantification of five macrolide antibiotics in several tissues, eggs and milk by liquid chromatography-electrospray tandem mass spectrometry.

PubMed

Dubois, M; Fluchard, D; Sior, E; Delahaut, P

2001-04-05

We present an electrospray high-performance liquid chromatographic tandem mass spectrometric (HPLC-MS-MS) method capable of determining in several tissues (muscle, kidney, liver), eggs and milk the following five macrolides: tylosin, tilmicosin, spiramycin, josamycin, erythromycin. Roxithromycin was used as an internal standard. The method uses extraction in a Tris buffer at pH 10.5, followed by protein precipitation with sodium tungstate and clean-up on an Oasis solid-phase extraction column. The HPLC separation was performed on a Purospher C18 column (125 x 3 mm I.D.) protected by a guard column, with a gradient of aqueous 0.1 M ammonium acetate-acetonitrile as the mobile phase at a flow-rate of 0.7 ml min(-1). Protonated molecules served as precursor ions for electrospray ionisation in the positive ion mode and four product ions were chosen for each analyte for multiple reaction monitoring (MRM). A validation study was conducted to confirm the five macrolides by MRM HPLC-MS-MS analysis of a negative control and fortified samples. All of the samples analysed were confirmed with four ions. The ion ratio reproducibility limit ranged from 2.4 to 15%. All compounds could be detected and quantified at half-maximum residue limits (MRLs). The method is specific, quantitative and reproducible enough to conform to European Union recommendations within the concentration range 0.5 MRL-2 MRL (accuracy: 80 to 110%, relative standard deviation: 2 to 13%). This whole method allows extraction and analysis of up to 50 samples per day.

Cleanup Verification Package for the 118-C-1, 105-C Solid Waste Burial Ground

DOE Office of Scientific and Technical Information (OSTI.GOV)

M. J. Appel and J. M. Capron

2007-07-25

This cleanup verification package documents completion of remedial action for the 118-C-1, 105-C Solid Waste Burial Ground. This waste site was the primary burial ground for general wastes from the operation of the 105-C Reactor and received process tubes, aluminum fuel spacers, control rods, reactor hardware, spent nuclear fuel and soft wastes.

Impact of pH on the stability and the cross-reactivity of ochratoxin A and citrinin.

PubMed

Bazin, Ingrid; Faucet-Marquis, Virginie; Monje, Marie-Carmen; El Khoury, Micheline; Marty, Jean-Louis; Pfohl-Leszkowicz, Annie

2013-11-28

Mycotoxins are secondary metabolites produced by several fungi contaminating crops. In several countries, the maximum permitted levels of mycotoxins are found in foodstuffs and feedstuffs. The common strategy of mycotoxin analysis involves extraction, clean-up and quantification by chromatography. In this paper, we analyzed the reasons of underestimation of ochratoxin A (OTA) content in wine, and overestimation of OTA in wheat, depending on the pH of the clean-up step and the simultaneous presence of citrinin (CIT). We demonstrated that the increase of pH by adding polyethylene glycol (PEG) to wine led to an underestimation of OTA by conversion of OTA into open ring ochratoxin A OP-OA. In comparing three methods of extraction and clean-up for the determination of OTA and CIT in wheat--(i) an inter-laboratory validated method for OTA in cereals using immunoaffinity column clean-up (IAC) and extraction by acetonitrile/water; (ii) a validated method using IAC and extraction with 1% bicarbonate Na; and (iii) an in-house validated method based on acid liquid/liquid extraction--we observed an overestimation of OTA after immunoaffinity clean-up when CIT is also present in the sample, whereas an underestimation was observed when OTA was alone. Under neutral and alkaline conditions, CIT was partially recognized by OTA antibodies.

Chapter 3. Determination of semivolatile organic compounds and polycyclic aromatic hydrocarbons in solids by gas chromatography/mass spectrometry

USGS Publications Warehouse

Zaugg, Steven D.; Burkhardt, Mark R.; Burbank, Teresa L.; Olson, Mary C.; Iverson, Jana L.; Schroeder, Michael P.

2006-01-01

A method for the determination of 38 polycyclic aromatic hydrocarbons (PAHs) and semivolatile organic compounds in solid samples is described. Samples are extracted using a pressurized solvent extraction system. The compounds of interest are extracted from the solid sample twice at 13,800 kilopascals; first at 120 degrees Celsius using a water/isopropyl alcohol mixture (50:50, volume-to-volume ratio), and then the sample is extracted at 200 degrees Celsius using a water/isopropyl alcohol mixture (80:20, volume-to-volume ratio). The compounds are isolated using disposable solid-phase extraction (SPE) cartridges containing divinylbenzene-vinylpyrrolidone copolymer resin. The cartridges are dried with nitrogen gas, and then sorbed compounds are eluted from the SPE material using a dichloromethane/diethyl ether mixture (80:20, volume-to-volume ratio) and passed through a sodium sulfate/Florisil SPE cartridge to remove residual water and to further clean up the extract. The concentrated extract is solvent exchanged into ethyl acetate and the solvent volume reduced to 0.5 milliliter. Internal standard compounds are added prior to analysis by capillary-column gas chromatography/mass spectrometry. Comparisons of PAH data for 28 sediment samples extracted by Soxhlet and the accelerated solvent extraction (ASE) method described in this report produced similar results. Extraction of PAH compounds from standard reference material using this method also compared favorably with Soxhlet extraction. The recoveries of PAHs less than molecular weight 202 (pyrene or fluoranthene) are higher by up to 20 percent using this ASE method, whereas the recoveries of PAHs greater than or equal to molecular weight 202 are equivalent. This ASE method of sample extraction of solids has advantages over conventional Soxhlet extraction by increasing automation of the extraction process, reducing extraction time, and using less solvent. Extract cleanup also is greatly simplified because SPE replaces commonly used gel permeation chromatography. The performance of the method (as expressed by mean recoveries and mean precision) was determined using Ottawa sand, a commercially available topsoil, and an environmental stream sediment, fortified at 1.5 and 15 micrograms per compound. Recoveries of PAH and semivolatile compounds in Ottawa sand samples fortified at 1.5 micrograms averaged 88 percent ? 9.4 percent relative standard deviation, and calculated initial method detection limits per compound averaged 14 micrograms per kilogram, assuming a 25-gram sample size. The recovery for 1,2,4-trichlorobenzene is less than 60 percent; thus, the concentration of this compound will always be reported as estimated with the E remark code. The analysis of 25 alkylated PAH homolog groups also can be determined with this method with extra data analysis and review, but because of the lack of authentic reference standard compounds, these results are considered to be semiquantitative. The PAH homolog groups are quantitated using the response factor of a parent PAH method compound, if available. Precision data for the alkylated PAH homologs detected in a marine sediment standard reference material (SRM 1944) also are presented to document and demonstrate method capability.

A twin purification/enrichment procedure based on two versatile solid/liquid extracting agents for efficient uptake of ultra-trace levels of lorazepam and clonazepam from complex bio-matrices.

PubMed

Hemmati, Maryam; Rajabi, Maryam; Asghari, Alireza

2017-11-17

In this research work, two consecutive dispersive solid/liquid phase microextractions based on efficient extraction media were developed for the influential and clean pre-concentration of clonazepam and lorazepam from complicated bio-samples. The magnetism nature of the proposed nanoadsorbent proceeded the clean-up step conveniently and swiftly (∼5min), pursued by a further enrichment via a highly effective and rapid emulsification microextraction process (∼4min) based on a deep eutectic solvent (DES). Finally, the instrumental analysis step was practicable via high performance liquid chromatography-ultraviolet detection. The solid phase used was an adequate magnetic nanocomposite termed as polythiophene-sodium dodecyl benzene sulfonate/iron oxide (PTh-DBSNa/Fe 3 O 4 ), easily and cost-effectively prepared by the impressive co-precipitation method followed by the efficient in situ sonochemical oxidative polymerization approach. The identification techniques viz. FESEM, XRD, and EDX certified the supreme physico-chemical properties of this effective nanosorbent. Also the powerful liquid extraction agent, DES, based on bio-degradable choline chloride, possessed a high efficiency, tolerable safety, low cost, and facile and mild synthesis route. The parameters involved in this versatile hyphenated procedure, efficiently evaluated via the central composite design (CCD), showed that the best extraction conditions consisted of an initial pH value of 7.2, 17mg of the PTh-DBSNa/Fe 3 O 4 nanocomposite, 20 air-agitation cycles (first step), 245μL of methanol, 250μL of DES, 440μL of THF, and 8 air-agitation cycles (second step). Under the optimal conditions, the understudied drugs could be accurately determined in the wide linear dynamic ranges (LDRs) of 4.0-3000ngmL -1 and 2.0-2000ngmL -1 for clonazepam and lorazepam, respectively, with low limits of detection (LODs) ranged from 0.7 to 1.0ngmL -1 . The enrichment factor (EF) and percentage extraction recovery (%ER) values were found to be 75 and 57% for clonazepam and 56 and 42% for lorazepam at the spiked level of 75.0ngmL -1 , possessing proper repeatabilities (relative standard deviation values (RSDs) below 5.9%, n=3). These valid analytical features provided quite accurate drug analyses at therapeutically low spans and levels below potentially toxic domains, implying a proper purification/enrichment of the proposed microextraction procedure. Copyright © 2017 Elsevier B.V. All rights reserved.

Microwave assisted solid phase extraction for separation preconcentration sulfamethoxazole in wastewater using tyre based activated carbon as solid phase material prior to spectrophotometric determination.

PubMed

Mogolodi Dimpe, K; Mpupa, Anele; Nomngongo, Philiswa N

2018-01-05

This work was chiefly encouraged by the continuous consumption of antibiotics which eventually pose harmful effects on animals and human beings when present in water systems. In this study, the activated carbon (AC) was used as a solid phase material for the removal of sulfamethoxazole (SMX) in wastewater samples. The microwave assisted solid phase extraction (MASPE) as a sample extraction method was employed to better extract SMX in water samples and finally the analysis of SMX was done by the UV-Vis spectrophotometer. The microwave assisted solid phase extraction method was optimized using a two-level fractional factorial design by evaluating parameters such as pH, mass of adsorbent (MA), extraction time (ET), eluent ratio (ER) and microwave power (MP). Under optimized conditions, the limit of detection (LOD) and limit of quantification (LOQ) were 0.5μgL -1 and 1.7μgL -1 , respectively, and intraday and interday precision expressed in terms of relative standard deviation were >6%.The maximum adsorption capacity was 138mgg -1 for SMX and the adsorbent could be reused eight times. Lastly, the MASPE method was applied for the removal of SMX in wastewater samples collected from a domestic wastewater treatment plant (WWTP) and river water. Copyright © 2017 Elsevier B.V. All rights reserved.

The Solid Phase Curing Time Effect of Asbuton with Texapon Emulsifier at the Optimum Bitumen Content

NASA Astrophysics Data System (ADS)

Sarwono, D.; Surya D, R.; Setyawan, A.; Djumari

2017-07-01

Buton asphalt (asbuton) could not be utilized optimally in Indonesia. Asbuton utilization rate was still low because the processed product of asbuton still have impracticable form in the term of use and also requiring high processing costs. This research aimed to obtain asphalt products from asbuton practical for be used through the extraction process and not requiring expensive processing cost. This research was done with experimental method in laboratory. The composition of emulsify asbuton were 5/20 grain, premium, texapon, HCl, and aquades. Solid phase was the mixture asbuton 5/20 grain and premium with 3 minutes mixing time. Liquid phase consisted texapon, HCl and aquades. The aging process was done after solid phase mixing process in order to reaction and tie of solid phase mixed become more optimal for high solubility level of asphalt production. Aging variable time were 30, 60, 90, 120, and 150 minutes. Solid and liquid phase was mixed for emulsify asbuton production, then extracted for 25 minutes. Solubility level of asphalt, water level, and asphalt characteristic was tested at extraction result of emulsify asbuton with most optimum ashphal level. The result of analysis tested data asphalt solubility level at extract asbuton resulted 94.77% on 120 minutes aging variable time. Water level test resulted water content reduction on emulsify asbuton more long time on occurring of aging solid phase. Examination of asphalt characteristic at extraction result of emulsify asbuton with optimum asphalt solubility level, obtain specimen that have rigid and strong texture in order that examination result have not sufficient ductility and penetration value.

Fluidics platform and method for sample preparation

DOEpatents

Benner, Henry W.; Dzenitis, John M.

2016-06-21

Provided herein are fluidics platforms and related methods for performing integrated sample collection and solid-phase extraction of a target component of the sample all in one tube. The fluidics platform comprises a pump, particles for solid-phase extraction and a particle-holding means. The method comprises contacting the sample with one or more reagents in a pump, coupling a particle-holding means to the pump and expelling the waste out of the pump while the particle-holding means retains the particles inside the pump. The fluidics platform and methods herein described allow solid-phase extraction without pipetting and centrifugation.

Efficient removal of recalcitrant deep-ocean dissolved organic matter during hydrothermal circulation

NASA Astrophysics Data System (ADS)

Hawkes, Jeffrey A.; Rossel, Pamela E.; Stubbins, Aron; Butterfield, David; Connelly, Douglas P.; Achterberg, Eric P.; Koschinsky, Andrea; Chavagnac, Valérie; Hansen, Christian T.; Bach, Wolfgang; Dittmar, Thorsten

2015-11-01

Oceanic dissolved organic carbon (DOC) is an important carbon pool, similar in magnitude to atmospheric CO2, but the fate of its oldest forms is not well understood. Hot hydrothermal circulation may facilitate the degradation of otherwise un-reactive dissolved organic matter, playing an important role in the long-term global carbon cycle. The oldest, most recalcitrant forms of DOC, which make up most of oceanic DOC, can be recovered by solid-phase extraction. Here we present measurements of solid-phase extractable DOC from samples collected between 2009 and 2013 at seven vent sites in the Atlantic, Pacific and Southern oceans, along with magnesium concentrations, a conservative tracer of water circulation through hydrothermal systems. We find that magnesium and solid-phase extractable DOC concentrations are correlated, suggesting that solid-phase extractable DOC is almost entirely lost from solution through mineralization or deposition during circulation through hydrothermal vents with fluid temperatures of 212-401 °C. In laboratory experiments, where we heated samples to 380 °C for four days, we found a similar removal efficiency. We conclude that thermal degradation alone can account for the loss of solid-phase extractable DOC in natural hydrothermal systems, and that its maximum lifetime is constrained by the timescale of hydrothermal cycling, at about 40 million years.

Recent developments and future trends in solid phase microextraction techniques towards green analytical chemistry.

PubMed

Spietelun, Agata; Marcinkowski, Łukasz; de la Guardia, Miguel; Namieśnik, Jacek

2013-12-20

Solid phase microextraction find increasing applications in the sample preparation step before chromatographic determination of analytes in samples with a complex composition. These techniques allow for integrating several operations, such as sample collection, extraction, analyte enrichment above the detection limit of a given measuring instrument and the isolation of analytes from sample matrix. In this work the information about novel methodological and instrumental solutions in relation to different variants of solid phase extraction techniques, solid-phase microextraction (SPME), stir bar sorptive extraction (SBSE) and magnetic solid phase extraction (MSPE) is presented, including practical applications of these techniques and a critical discussion about their advantages and disadvantages. The proposed solutions fulfill the requirements resulting from the concept of sustainable development, and specifically from the implementation of green chemistry principles in analytical laboratories. Therefore, particular attention was paid to the description of possible uses of novel, selective stationary phases in extraction techniques, inter alia, polymeric ionic liquids, carbon nanotubes, and silica- and carbon-based sorbents. The methodological solutions, together with properly matched sampling devices for collecting analytes from samples with varying matrix composition, enable us to reduce the number of errors during the sample preparation prior to chromatographic analysis as well as to limit the negative impact of this analytical step on the natural environment and the health of laboratory employees. Copyright © 2013 Elsevier B.V. All rights reserved.

Determination of ultraviolet filters in bathing waters by stir bar sorptive-dispersive microextraction coupled to thermal desorption-gas chromatography-mass spectrometry.

PubMed

Benedé, Juan L; Chisvert, Alberto; Giokas, Dimosthenis L; Salvador, Amparo

2016-01-15

In this work, a new approach that combines the advantages of stir bar sorptive extraction (SBSE) and dispersive solid phase extraction (DSPE), i.e. stir bar sorptive-dispersive microextraction (SBSDµE), is employed as enrichment and clean-up technique for the sensitive determination of eight lipophilic UV filters in water samples. The extraction is accomplished using a neodymium stir bar magnetically coated with oleic acid-coated cobalt ferrite magnetic nanoparticles (MNPs) as sorbent material, which are detached and dispersed into the solution at high stirring rate. When stirring is stopped, MNPs are magnetically retrieved onto the stir bar, which is subjected to thermal desorption (TD) to release the analytes into the gas chromatography-mass spectrometry (GC-MS) system. The SBSDµE approach allows for lower extraction time than SBSE and easier post-extraction treatment than DSPE, while TD allows for an effective and solvent-free injection of the entire quantity of desorbed analytes into GC-MS, and thus achieving a high sensitivity. The main parameters involved in TD, as well as the extraction time, were evaluated. Under the optimized conditions, the method was successfully validated showing good linearity, limits of detection and quantification in the low ngL(-1) range and good intra- and inter-day repeatability (RSD<12%). This accurate and sensitive analytical method was applied to the determination of trace amounts of UV filters in three bathing water samples (river, sea and swimming pool) with satisfactory relative recovery values (80-116%). Copyright © 2015 Elsevier B.V. All rights reserved.

Optimisation and validation of the analytical procedure for the determination of acrylamide in coffee by LC-MS/MS with SPE clean up.

PubMed

Gielecińska, Iwona; Mojska, Hanna

2013-01-01

Numerous studies have demonstrated acrylamide to be both neurotoxic and carcinogenic. At present it is widely recognised that acrylamide is mainly formed through the Maillard reaction from free asparagine and reducing sugars. The major sources of dietary acrylamide are potato products, processed cereals and coffee. To optimise and validate an analytical method for determining acrylamide in coffee by liquid chromatography and tandem mass spectrometry analysis (LC/MS/MS) using SPE clean-up. Analytical separation of acrylamide from roasted coffee was performed by liquid chromatography using a Hypercarb column followed by LC/MS/MS analysis, with 2,3,3-d3 acrylamide as an internal standard. The method was based on two purification steps: the first with hexane and Carrez solutions in order to remove of fat and to precipitate proteins, respectively; and the second with a solid-phase extraction (SPE) column which proved to be efficient in the elimination of the main chromatographic interferences. Limit of quantification (LOQ) for measuring acrylamide in coffee was 50 microg/kg. The described method demonstrates satisfactory precision (RSD = 2.5%), repeatability (RSD = 9.2%) and accuracy (mean recovery - 97.4%). Our results confirm that LC-MS/MS with SPE clean-up is selective and suitable for determination of acrylamide in coffee. Indeed, this method meets the criteria of EU Commission Recommendations (No. 2007/331/EC and No. 2010/307/EU), on the monitoring of acrylamide levels in food.

Polypyrrole-magnetite dispersive micro-solid-phase extraction combined with ultraviolet-visible spectrophotometry for the determination of rhodamine 6G and crystal violet in textile wastewater.

PubMed

Kamaruddin, Amirah Farhan; Sanagi, Mohd Marsin; Wan Ibrahim, Wan Aini; Md Shukri, Dyia S; Abdul Keyon, Aemi S

2017-11-01

Polypyrrole-magnetite dispersive micro-solid-phase extraction method combined with ultraviolet-visible spectrophotometry was developed for the determination of selected cationic dyes in textile wastewater. Polypyrrole-magnetite was used as adsorbent due to its thermal stability, magnetic properties, and ability to adsorb Rhodamine 6G and crystal violet. Dispersive micro-solid-phase extraction parameters were optimized, including sample pH, adsorbent amount, extraction time, and desorption solvent. The optimum polypyrrole-magnetite dispersive micro-solid phase-extraction conditions were sample pH 8, 60 mg polypyrrole-magnetite adsorbent, 5 min of extraction time, and acetonitrile as the desorption solvent. Under the optimized conditions, the polypyrrole-magnetite dispersive micro-solid-phase extraction with ultraviolet-visible method showed good linearity in the range of 0.05-7 mg/L (R 2  > 0.9980). The method also showed a good limit of detection for the dyes (0.05 mg/L) and good analyte recoveries (97.4-111.3%) with relative standard deviations < 10%. The method was successfully applied to the analysis of dyes in textile wastewater samples where the concentration found was 1.03 mg (RSD ±7.9%) and 1.13 mg/L (RSD ± 4.6%) for Rhodamine 6G and crystal violet, respectively. It can be concluded that this method can be adopted for the rapid extraction and determination of dyes at trace concentration levels. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Application of mercapto-silica polymerized high internal phase emulsions for the solid-phase extraction and preconcentration of trace lead(II).

PubMed

Su, Rihui; Ruan, Guihua; Chen, Zhengyi; Du, Fuyou; Li, Jianping

2015-12-01

A new class of solid-phase extraction column prepared with grafted mercapto-silica polymerized high internal phase emulsion particles was used for the preconcentration of trace lead. First, mercapto-silica polymerized high internal phase emulsion particles were synthesized by using high internal phase emulsion polymerization and carefully assembled in a polyethylene syringe column. The influences of various parameters including adsorption pH value, adsorption and desorption solvents, flow rate of the adsorption and desorption procedure were optimized, respectively, and the suitable uploading sample volumes, adsorption capacity, and reusability of solid phase extraction column were also investigated. Under the optimum conditions, Pb(2+) could be preconcentrated quantitatively over a wide pH range (2.0-5.0). In the presence of foreign ions, such as Na(+) , K(+) , Ca(2+) , Zn(2+) , Mg(2+) , Cu(2+) , Fe(2+) , Cd(2+) , Cl(-) and NO3 (-) , Pb(2+) could be recovered successfully. The prepared solid-phase extraction column performed with high stability and desirable durability, which allowed more than 100 replicate extractions without measurable changes of performance. The feasibility of the developed method was further validated by the extraction of Pb(2+) in rice samples. At three spiked levels of 40.0, 200 and 800 μg/kg, the average recoveries for Pb(2+) in rice samples ranged from 87.3 to 105.2%. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Molecularly imprinted polymer online solid-phase extraction coupled with high-performance liquid chromatography-UV for the determination of three sulfonamides in pork and chicken.

PubMed

He, Jinxing; Wang, Shuo; Fang, Guozhen; Zhu, Huaping; Zhang, Yan

2008-05-14

A selective imprinted amino-functionalized silica gel sorbent was prepared by combining a surface molecular imprinting technique with a sol-gel process for online solid-phase extraction-HPLC determination of three trace sulfonamides in pork and chicken muscle. The imprinted functionalized silica gel sorbent exhibited selectivity and fast kinetics for the adsorption and desorption of sulfonamides. With a sample loading flow rate of 4 mL min (-1) for 12.5 min, enhancement factors and detection limits for three sulfonamides ( S/ N = 3) were achieved. The precision (RSD) for nine replicate online sorbent extractions of 5 microg L (-1) sulfonamides was less than 4.5%. The sorbent also offered good linearity ( r (2) > 0.99) for online solid-phase extraction of trace levels of sulfonamides. The method was applied to the determination of sulfonamides in pork and chicken muscle samples. The prepared polymer sorbent shows promise for online solid-phase extraction for HPLC determination of trace levels of sulfonamides in pork and chicken samples.

Study of acrylamide in coffee using an improved liquid chromatography mass spectrometry method: Investigation of colour changes and acrylamide formation in coffee during roasting.

PubMed

Senyuva, Hamide Z; Gökmen, Vural

2005-03-01

An improved analytical method for the determination of acrylamide in coffee is described using liquid chromatography coupled to mass spectrometric detection (LC-MS). A variety of instant, ground and laboratory roasted coffee samples were analysed using this method. The sample preparation entails extraction of acrylamide with methanol, purification with Carrez I and II solutions, evaporation and solvent change to water, and clean-up with an Oasis HLB solid-phase extraction (SPE) cartridge. The chromatographic conditions allowed separation of acrylamide and the remaining matrix co-extractives with accurate and precise quantification of acrylamide during MS detection in SIM mode. Recoveries for the spiking levels of 50, 100, 250 and 500?microg/kg ranged between 99 and 100% with relative standard deviations of less than 2%. The effects of roasting on the formation of acrylamide and colour development were also investigated at 150, 200 and 225 degrees C. Change in the CIE (Commission Internationale de l'Eclairage) a* colour value was found to show a good correlation with the change in acrylamide. CIE a* and acrylamide data was fitted to a non-linear logarithmic function for the estimation of acrylamide level in coffee. Measured acrylamide levels in commercial roasted coffees compared well with the predicted acrylamide levels from the CIE a* values.

Comparison of characteristic flavor and aroma volatiles in melons and standards using solid phase microextraction (SPME) and Stir Bar Sorptive Extraction (SBSE) with GC-MS.

USDA-ARS?s Scientific Manuscript database

Stir bar sorptive extraction (SBSE) is a technique for extraction and analysis of organic compounds in aqueous matrices, similar in theory to solid phase microextraction (SPME). SBSE has been successfully used to analyze several organic compounds, including food matrices. When compared with SPME, ...

QUANTITATION OF ESTROGENS IN GROUND WATER AND SWINE LAGOON SAMPLE USING SOLID PHASE EXTRACTION, PENTAFLUROBENZYL/TRIMETHYLSILYL DERIVATIZATIONS AND GAS CHROMATOGRAPHY NEGATIVE ION CHEMICAL IONIZATION/MASS SPECTROMETRY/MASS SPECTROMETRY

EPA Science Inventory

A method was developed for the confirmed identification and quantitation of 17B-estradiol, estrone, 17B-ethynylestrodial and 16a-hydroxy-17B-estradiol (estriol) in ground water and swine lagoon samples. Centrifuged and filtered samples were extracted using solid phase extraction...

Semiautomated solid-phase extraction manifold with a solvent-level sensor.

PubMed

Orlando, R M; Rath, S; Rohwedder, J J R

2013-11-15

A semiautomated solid-phase extraction manifold for multiple extractions is presented. The manifold utilizes commercial solid-phase syringe cartridges and automatically introduces and elutes all the solvents during the extraction, reducing the typical workload and stress of the analyst. The manifold consists of a peristaltic pump with solenoid valves in a flow circuit that contains transmissive photomicrosensors. The photomicrosensors were used to control the solvent dispenser and the solvent level inside the cartridge. As solvent-level sensors, the photomicrosensors determined the exact time the solvent reached the top frit to avoid sorbent drying and accurately perform the solvent exchange. The repeatability of the manifold to introduce a particular volume of solvent into the cartridges was measured, and the precisions were between 0.05 and 2.89% (RSD). To evaluate the manifold, the amount of two fluoroquinolones in a fortified blank milk sample was determined. The results of the intra- and inter-day precision of multiple extractions from the fortified milk samples resulted in precisions better than 9.0% (RSD) and confirmed that the arrangement of the semiautomated manifold could adequately be used in solid-phase extraction with commercial cartridges. Copyright © 2013 Elsevier B.V. All rights reserved.

Selective trace enrichment of chlorotriazine pesticides from natural waters and sediment samples using terbuthylazine molecularly imprinted polymers

USGS Publications Warehouse

Ferrer, I.; Lanza, F.; Tolokan, A.; Horvath, V.; Sellergren, B.; Horvai, G.; Barcelo, D.

2000-01-01

Two molecularly imprinted polymers were synthesized using either dichloromethane or toluene as the porogen and terbuthylazine as the template and were used as solid-phase extraction cartridges for the enrichment of six chlorotriazines (deisopropylatrazine, deethylatrazine, simazine, atrazine, propazine, and terbuthylazine) in natural water and sediment samples. The extracted samples were analyzed by liquid chromatography/diode array detection (LC/DAD). Several washing solvents, as well as different volumes, were tested for their ability to remove the matrix components nonspecifically adsorbed on the sorbents. This cleanup step was shown to be of prime importance to the successful extraction of the pesticides from the aqueous samples. The optimal analytical conditions were obtained when the MIP imprinted using dichloromethane was the sorbent, 2 mL of dichloromethane was used in the washing step, and the preconcentrated analytes were eluted with 8 mL of methanol. The recoveries were higher than 80% for all the chlorotriazines except for propazine (53%) when 50- or 100-mL groundwater samples, spiked at 1 ??g/L level, were analyzed. The limits of detection varied from 0.05 to 0.2 ??g/L when preconcentrating a 100-mL groundwater sample. Natural sediment samples from the Ebre Delta area (Tarragona, Spain) containing atrazine and deethylatrazine were Soxhlet extracted and analyzed by the methodology developed in this work. No significant interferences from the sample matrix were noticed, thus indicating good selectivity of the MIP sorbents used.

Development and validation of an improved method for the determination of chloropropanols in paperboard food packaging by GC-MS.

PubMed

Mezouari, S; Liu, W Yun; Pace, G; Hartman, T G

2015-01-01

The objective of this study was to develop an improved analytical method for the determination of 3-chloro-1,2-propanediol (3-MCPD) and 1,3-dichloropropanol (1,3-DCP) in paper-type food packaging. The established method includes aqueous extraction, matrix spiking of a deuterated surrogate internal standard (3-MCPD-d₅), clean-up using Extrelut solid-phase extraction, derivatisation using a silylation reagent, and GC-MS analysis of the chloropropanols as their corresponding trimethyl silyl ethers. The new method is applicable to food-grade packaging samples using European Commission standard aqueous extraction and aqueous food stimulant migration tests. In this improved method, the derivatisation procedure was optimised; the cost and time of the analysis were reduced by using 10 times less sample, solvents and reagents than in previously described methods. Overall the validation data demonstrate that the method is precise and reliable. The limit of detection (LOD) of the aqueous extract was 0.010 mg kg(-1) (w/w) for both 3-MCPD and 1,3-DCP. Analytical precision had a relative standard deviation (RSD) of 3.36% for 3-MCPD and an RSD of 7.65% for 1,3-DCP. The new method was satisfactorily applied to the analysis of over 100 commercial paperboard packaging samples. The data are being used to guide the product development of a next generation of wet-strength resins with reduced chloropropanol content, and also for risk assessments to calculate the virtual safe dose (VSD).

Separation and purification of thymopentin with molecular imprinting membrane by solid phase extraction disks.

PubMed

Wang, Chaoli; Hu, Xiaoling; Guan, Ping; Wu, Danfeng; Qian, Liwei; Li, Ji; Song, Renyuan

2015-01-01

The synthesis and performance of molecularly imprinted membranes (MIMs) as a solid phase extraction packing materials for the separation and purification of thymopentin from crude samples was described. In order to increase structural selectivity and imprinting efficiency, surface-initiated ATRP and ionic liquid (1-vinyl-3-ethyl acetate imidazolium chloride) were used to prepare molecularly imprinting membranes. The results demonstrated that solid phase extraction disks stuffed by MIMs with ionic liquids as functional monomer demonstrated high isolation and purification of performance to the thymopentin. The molecular recognition of thymopentin was analyzed by using molecular modeling software. Copyright © 2014 Elsevier B.V. All rights reserved.

Determination of the Antibiotic Oxytetracycline in Commercial Milk by Solid-Phase Extraction: A High-Performance Liquid Chromatography (HPLC) Experiment for Quantitative Instrumental Analysis

ERIC Educational Resources Information Center

Mei-Ratliff, Yuan

2012-01-01

Trace levels of oxytetracylcine spiked into commercial milk samples are extracted, cleaned up, and preconcentrated using a C[subscript 18] solid-phase extraction column. The extract is then analyzed by a high-performance liquid chromatography (HPLC) instrument equipped with a UV detector and a C[subscript 18] column (150 mm x 4.6 mm x 3.5 [mu]m).…

Selective extraction and separation of oxymatrine from Sophora flavescens Ait. extract by silica-confined ionic liquid.

PubMed

Bi, Wentao; Tian, Minglei; Row, Kyung Ho

2012-01-01

This study highlighted the application of a two-stepped extraction method for extraction and separation of oxymatrine from Sophora flavescens Ait. extract by utilizing silica-confined ionic liquids as sorbent. The optimized silica-confined ionic liquid was firstly mixed with plant extract to adsorb oxymatrine. Simultaneously, some interference, such as matrine, was removed. The obtained suspension was then added to a cartridge for solid phase extraction. Through these two steps, target compound was adequately separated from interferences with 93.4% recovery. In comparison with traditional solid phase extraction, this method accelerates loading and reduces the use of organic solvents during washing. Moreover, the optimization of loading volume was simplified as optimization of solid/liquid ratio. Copyright © 2011 Elsevier B.V. All rights reserved.

Platform construction and extraction mechanism study of magnetic mixed hemimicelles solid-phase extraction

NASA Astrophysics Data System (ADS)

Xiao, Deli; Zhang, Chan; He, Jia; Zeng, Rong; Chen, Rong; He, Hua

2016-12-01

Simple, accurate and high-throughput pretreatment method would facilitate large-scale studies of trace analysis in complex samples. Magnetic mixed hemimicelles solid-phase extraction has the power to become a key pretreatment method in biological, environmental and clinical research. However, lacking of experimental predictability and unsharpness of extraction mechanism limit the development of this promising method. Herein, this work tries to establish theoretical-based experimental designs for extraction of trace analytes from complex samples using magnetic mixed hemimicelles solid-phase extraction. We selected three categories and six sub-types of compounds for systematic comparative study of extraction mechanism, and comprehensively illustrated the roles of different force (hydrophobic interaction, π-π stacking interactions, hydrogen-bonding interaction, electrostatic interaction) for the first time. What’s more, the application guidelines for supporting materials, surfactants and sample matrix were also summarized. The extraction mechanism and platform established in the study render its future promising for foreseeable and efficient pretreatment under theoretical based experimental design for trace analytes from environmental, biological and clinical samples.

Cleanup Verification Package for the 618-8 Burial Ground

DOE Office of Scientific and Technical Information (OSTI.GOV)

M. J. Appel

2006-08-10

This cleanup verification package documents completion of remedial action for the 618-8 Burial Ground, also referred to as the Solid Waste Burial Ground No. 8, 318-8, and the Early Solid Waste Burial Ground. During its period of operation, the 618-8 site is speculated to have been used to bury uranium-contaminated waste derived from fuel manufacturing, and construction debris from the remodeling of the 313 Building.

Multiresidue method for N-methyl carbamates and metabolite pesticide residues at the parts-per-billion level in selected representative commodities of fruit and vegetable crop groups.

PubMed

Podhorniak, Lynda V; Schenck, Frank J; Krynitsky, Alexander; Griffith, Francis

2004-01-01

A reversed-phase liquid chromatographic method with both fluorescence and mass spectrometric detection is presented for the determination of 13 parent N-methyl carbamate pesticides and their metabolites, as well as piperonyl butoxide, for a total of 24 compounds in selected fruits and vegetables. The commodities chosen were of special concern to the U.S. Environmental Protection Agency (EPA) because they had the least amount of monitoring data for dietary exposure estimates used in risk assessment. The method is based on a judicious selection of procedures from U.S. Food and Drug Administration sources such as the Pesticide Analytical Manual (Volume I), and Laboratory Information Bulletins, plus additional material from the chemical literature combined in a manner to recover the N-methyl carbamates and their metabolites at the 1 microg/kg or 1 part-per-billion level. The method uses an acetone extraction, followed by an aminopropyl solid-phase extraction cleanup. Determination of residues is by RP-LC, in which the liquid chromatograph is interfaced with either a fluorescence or a mass spectrometric detector. The method is designed so that a set of 6 samples can be prepared in 1 working day for overnight instrumental analysis. Recovery data are presented from analyses of selected commodities in some of EPA's fruit and vegetable crop groupings. A table listing relative retention times is presented for the N-methyl carbamates and their metabolites.

Qualitative screening of veterinary anti-microbial agents in tissues, milk, and eggs of food-producing animals using liquid chromatography coupled with tandem mass spectrometry.

PubMed

Chen, Dongmei; Yu, Jie; Tao, Yanfei; Pan, Yuanhu; Xie, Shuyu; Huang, Lingli; Peng, Dapeng; Wang, Xu; Wang, Yulian; Liu, Zhenli; Yuan, Zonghui

2016-04-01

A method for the analysis of 120 drugs in animal derived food was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). These analytes belong to 12 families of veterinary anti-microbial agents (quinolones, macrolides, β-lactams, nitroimidazoles, sulfonamides, lincomycines, chloramphenicols, quinoxalines, tetracyclines, polypeptides, and antibacterial synergists) as well as other compounds not assigned to a particular drug family. The animal derived food samples include muscle and liver of swine, bovine, sheep, and chicken, as well as hen eggs and dairy milk. The sample preparation included ultrasound-assisted extraction (UAE) with acetonitrile-water and a final clean-up with auto solid-phase extraction (SPE) on HLB cartridges. The detection and quantification of 120 anti-microbial agents was performed using LC-MS/MS in positive and negative ion mode. The chromatographic separation was performed on a C18 column using acetonitrile and 0.1% formic acid as the mobile phase. The limit of detection (LOD) and limit of quantification (LOQ) of all drugs in food-producing animals were 0.5-3.0μg/kg and 1.5-10.0μg/kg, respectively. The developed method was successfully utilized to monitor real samples, which demonstrated that it is a simple, fast, and robust method, and could be used as a regulatory to screen for the presence of residues from veterinary anti-microbial drugs in animal-derived foods. Copyright © 2016 Elsevier B.V. All rights reserved.

Magnetic dispersive solid-phase extraction based on modified magnetic nanoparticles for the detection of cocaine and cocaine metabolites in human urine by high-performance liquid chromatography-mass spectrometry.

PubMed

Yang, Feiyu; Zou, Yun; Ni, Chunfang; Wang, Rong; Wu, Min; Liang, Chen; Zhang, Jiabin; Yuan, Xiaoliang; Liu, Wenbin

2017-11-01

An easy-to-handle magnetic dispersive solid-phase extraction procedure was developed for preconcentration and extraction of cocaine and cocaine metabolites in human urine. Divinyl benzene and vinyl pyrrolidone functionalized silanized Fe 3 O 4 nanoparticles were synthesized and used as adsorbents in this procedure. Scanning electron microscopy, vibrating sample magnetometry, and infrared spectroscopy were employed to characterize the modified adsorbents. A high-performance liquid chromatography with mass spectrometry method for determination of cocaine and its metabolites in human urine sample has been developed with pretreatment of the samples by magnetic dispersive solid-phase extraction. The obtained results demonstrated the higher extraction capacity of the prepared nanoparticles with recoveries between 75.1 to 105.7% and correlation coefficients higher than 0.9971. The limits of detection for the cocaine and cocaine metabolites were 0.09-1.10 ng/mL. The proposed magnetic dispersive solid-phase extraction method provided a rapid, environmentally friendly and magnetic stuff recyclable approach and it was confirmed that the prepared adsorbents material was a kind of highly effective extraction materials for the trace cocaine and cocaine metabolites analyses in human urine. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of haloacetic acids in water using layered double hydroxides as a sorbent in dispersive solid-phase extraction followed by liquid chromatography with tandem mass spectrometry.

PubMed

Alsharaa, Abdulnaser; Sajid, Muhammad; Basheer, Chanbasha; Alhooshani, Khalid; Lee, Hian Kee

2016-09-01

In the present study, highly efficient and simple dispersive solid-phase extraction procedure for the determination of haloacetic acids in water samples has been established. Three different types of layered double hydroxides were synthesized and used as a sorbent in dispersive solid-phase extraction. Due to the interesting behavior of layered double hydroxides in an acidic medium (pH˂4), the analyte elution step was not needed; the layered double hydroxides are simply dissolved in acid immediately after extraction to release the analytes which are then directly introduced into a liquid chromatography with tandem mass spectrometry system for analysis. Several dispersive solid-phase extraction parameters were optimized to increase the extraction efficiency of haloacetic acids such as temperature, extraction time and pH. Under optimum conditions, good linearity was achieved over the concentration range of 0.05-100 μg/L with detection limits in the range of 0.006-0.05 μg/L. The relative standard deviations were 0.33-3.64% (n = 6). The proposed method was applied to different water samples collected from a drinking water plant to determine the concentrations of haloacetic acids. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mycoestrogen determination in cow milk: Magnetic solid-phase extraction followed by liquid chromatography and tandem mass spectrometry analysis.

PubMed

Capriotti, Anna Laura; Cavaliere, Chiara; Foglia, Patrizia; La Barbera, Giorgia; Samperi, Roberto; Ventura, Salvatore; Laganà, Aldo

2016-12-01

Recently, magnetic solid-phase extraction has gained interest because it presents various operational advantages over classical solid-phase extraction. Furthermore, magnetic nanoparticles are easy to prepare, and various materials can be used in their synthesis. In the literature, there are only few studies on the determination of mycoestrogens in milk, although their carryover in milk has occurred. In this work, we wanted to develop the first (to the best of our knowledge) magnetic solid-phase extraction protocol for six mycoestrogens from milk, followed by liquid chromatography and tandem mass spectrometry analysis. Magnetic graphitized carbon black was chosen as the adsorbent, as this carbonaceous material, which is very different from the most diffuse graphene and carbon nanotubes, had already shown selectivity towards estrogenic compounds in milk. The graphitized carbon black was decorated with Fe 3 O 4 , which was confirmed by the characterization analyses. A milk deproteinization step was avoided, using only a suitable dilution in phosphate buffer as sample pretreatment. The overall process efficiency ranged between 52 and 102%, whereas the matrix effect considered as signal suppression was below 33% for all the analytes even at the lowest spiking level. The obtained method limits of quantification were below those of other published methods that employ classical solid-phase extraction protocols. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reactor water cleanup system

DOEpatents

Gluntz, Douglas M.; Taft, William E.

1994-01-01

A reactor water cleanup system includes a reactor pressure vessel containing a reactor core submerged in reactor water. First and second parallel cleanup trains are provided for extracting portions of the reactor water from the pressure vessel, cleaning the extracted water, and returning the cleaned water to the pressure vessel. Each of the cleanup trains includes a heat exchanger for cooling the reactor water, and a cleaner for cleaning the cooled reactor water. A return line is disposed between the cleaner and the pressure vessel for channeling the cleaned water thereto in a first mode of operation. A portion of the cooled water is bypassed around the cleaner during a second mode of operation and returned through the pressure vessel for shutdown cooling.

A sensitive and accurate method for the determination of perfluoroalkyl and polyfluoroalkyl substances in human serum using a high performance liquid chromatography-online solid phase extraction-tandem mass spectrometry.

PubMed

Yu, Chang Ho; Patel, Bhupendra; Palencia, Marilou; Fan, Zhihua Tina

2017-01-13

A selective, sensitive, and accurate analytical method for the measurement of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in human serum, utilizing LC-MS/MS (liquid chromatography-tandem mass spectrometry), was developed and validated according to the Centers for Disease Control and Prevention (CDC) guidelines for biological sample analysis. Tests were conducted to determine the optimal analytical column, mobile phase composition and pH, gradient program, and cleaning procedure. The final analytical column selected for analysis was an extra densely bonded silica-packed reverse-phase column (Agilent XDB-C 8 , 3.0×100mm, 3.5μm). Mobile phase A was an aqueous buffer solution containing 10mM ammonium acetate (pH=4.3). Mobile phase B was a mixture of methanol and acetonitrile (1:1, v/v). The gradient program was programmed by initiating a fast elution (%B, from 40 to 65%) between 1.0 and 1.5min, followed by a slow elution (%B: 65-80%) in the period of 1.5-7.5min. The cleanup procedures were augmented by cleaning with (1) various solvents (isopropyl alcohol, methanol, acetonitrile, and reverse osmosis-purified water); (2) extensive washing steps for the autosampler and solid phase extraction (SPE) cartridge; and (3) a post-analysis cleaning step for the whole system. Under the above conditions, the resolution and sensitivity were significantly improved. Twelve target PFASs were baseline-separated (2.5-7.0min) within a 10-min of acquisition time. The limits of detection (LODs) were 0.01ng/mL or lower for all of the target compounds, making this method 5 times more sensitive than previously published methods. The newly developed method was validated in the linear range of 0.01-50ng/mL, and the accuracy (recovery between 80 and 120%) and precision (RSD<20%) were acceptable at three spiked levels (0.25, 2.5, and 25ng/mL). The method development and validation results demonstrated that this method was precise, accurate, and robust, with high-throughput (∼10min per sample); thus suitable for large-scale epidemiological studies. Published by Elsevier B.V.

COMPARISON OF TWO DIFFERENT SOLID PHASE EXTRACTION/LARGE VOLUME INJECTION PROCEDURES FOR METHOD 8270

EPA Science Inventory

Two solid phase (SPE) and one traditional continuous liquid-liquid extraction method are compared for analysis of Method 8270 SVOCs. Productivity parameters include data quality, sample volume, analysis time and solvent waste.

One SPE system, unique in the U.S., uses aut...

Analysis of ecologically relevant pharmaceuticals in wastewater and surface water using selective solid phase extraction and UPLC/MS/MS

EPA Science Inventory

A rapid and sensitive method has been developed for the analysis of 48 human prescription active pharmaceutical ingredients (APIs) and 6 metabolites of interest, utilizing selective solid-phase extraction (SPE) and ultra performance liquid chromatography in combination with tripl...

40 CFR 141.40 - Monitoring requirements for unregulated contaminants.

Code of Federal Regulations, 2011 CFR

2011-07-01

... monitoring to be completed Reserved i Reserved i Reserved i Reserved i Reserved i Reserved i Column headings... Pesticides and Flame Retardants in Drinking Water by Solid Phase Extraction and Capillary Column Gas... Water by Solid Phase Extraction and Capillary Column Gas Chromatography/Mass Spectrometry (GC/MS...

Development of a Solid Phase Extraction Method for Agricultural Pesticides in Large-Volume Water Samples

EPA Science Inventory

An analytical method using solid phase extraction (SPE) and analysis by gas chromatography/mass spectrometry (GC/MS) was developed for the trace determination of a variety of agricultural pesticides and selected transformation products in large-volume high-elevation lake water sa...

AUTOMATED SOLID PHASE EXTRACTION GC/MS FOR ANALYSIS OF SEMIVOLATILES IN WATER AND SEDIMENTS

EPA Science Inventory

Data is presented on the development of a new automated system combining solid phase extraction (SPE) with GC/MS spectrometry for the single-run analysis of water samples containing a broad range of organic compounds. The system uses commercially available automated in-line sampl...

Impact of pH on the Stability and the Cross-Reactivity of Ochratoxin A and Citrinin

PubMed Central

Bazin, Ingrid; Faucet-Marquis, Virginie; Monje, Marie-Carmen; El Khoury, Micheline; Marty, Jean-Louis; Pfohl-Leszkowicz, Annie

2013-01-01

Mycotoxins are secondary metabolites produced by several fungi contaminating crops. In several countries, the maximum permitted levels of mycotoxins are found in foodstuffs and feedstuffs. The common strategy of mycotoxin analysis involves extraction, clean-up and quantification by chromatography. In this paper, we analyzed the reasons of underestimation of ochratoxin A (OTA) content in wine, and overestimation of OTA in wheat, depending on the pH of the clean-up step and the simultaneous presence of citrinin (CIT). We demonstrated that the increase of pH by adding polyethylene glycol (PEG) to wine led to an underestimation of OTA by conversion of OTA into open ring ochratoxin A OP-OA. In comparing three methods of extraction and clean-up for the determination of OTA and CIT in wheat—(i) an inter-laboratory validated method for OTA in cereals using immunoaffinity column clean-up (IAC) and extraction by acetonitrile/water; (ii) a validated method using IAC and extraction with 1% bicarbonate Na; and (iii) an in-house validated method based on acid liquid/liquid extraction—we observed an overestimation of OTA after immunoaffinity clean-up when CIT is also present in the sample, whereas an underestimation was observed when OTA was alone. Under neutral and alkaline conditions, CIT was partially recognized by OTA antibodies. PMID:24287570

Development and validation of a magnetic solid-phase extraction with high-performance liquid chromatography method for the simultaneous determination of amphetamine and methadone in urine.

PubMed

Taghvimi, Arezou; Hamishehkar, Hamed; Ebrahimi, Mahmoud

2016-06-01

The simultaneous determination of amphetamine and methadone was carried out by magnetic graphene oxide nanoparticles, a magnetic solid-phase extraction adsorbent, as a new sample treatment technique. The main factors (the amounts of sample volume, amount of adsorbent, type and amount of extraction organic solvent, time of extraction and desorption, pH, the ionic strength of extraction medium, and agitation rate) influencing the extraction efficiency were investigated and optimized. Under the optimized conditions, good linearity was observed in the range of 100-1500 ng/mL for amphetamine and 100-1000 ng/mL for methadone. The method was evaluated for determination of AM and methadone in positive urine samples, satisfactory results were obtained, therefore magnetic solid-phase extraction can be applied as a novel method for the determination of drugs of abuse in forensic laboratories. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Towards an automatic lab-on-valve-ion mobility spectrometric system for detection of cocaine abuse.

PubMed

Cocovi-Solberg, David J; Esteve-Turrillas, Francesc A; Armenta, Sergio; de la Guardia, Miguel; Miró, Manuel

2017-08-25

A lab-on-valve miniaturized system integrating on-line disposable micro-solid phase extraction has been interfaced with ion mobility spectrometry for the accurate and sensitive determination of cocaine and ecgonine methyl ester in oral fluids. The method is based on the automatic loading of 500μL of oral fluid along with the retention of target analytes and matrix clean-up by mixed-mode cationic/reversed-phase solid phase beads, followed by elution with 100μL of 2-propanol containing (3% v/v) ammonia, which are online injected into the IMS. The sorptive particles are automatically discarded after every individual assay inasmuch as the sorptive capacity of the sorbent material is proven to be dramatically deteriorated with reuse. The method provided a limit of detection of 0.3 and 0.14μgL -1 for cocaine and ecgonine methyl ester, respectively, with relative standard deviation values from 8 till 14% with a total analysis time per sample of 7.5min. Method trueness was evaluated by analyzing oral fluid samples spiked with cocaine at different concentration levels (1, 5 and 25μgL -1 ) affording relative recoveries within the range of 85±24%. Fifteen saliva samples were collected from volunteers and analysed following the proposed automatic procedure, showing a 40% cocaine occurrence with concentrations ranging from 1.3 to 97μgL -1 . Field saliva samples were also analysed by reference methods based on lateral flow immunoassay and gas chromatography-mass spectrometry. The application of this procedure to the control of oral fluids of cocaine consumers represents a step forward towards the development of a point-of-care cocaine abuse sensing system. Copyright © 2017 Elsevier B.V. All rights reserved.

Screening method for the determination of tetracyclines and fluoroquinolones in animal drinking water by liquid chromatography with diode array detector.

PubMed

Patyra, E; Kowalczyk, E; Grelik, A; Przeniosło-Siwczyńska, M; Kwiatek, K

2015-01-01

A liquid chromatography - diode array detector (HPLC-DAD) procedure has been developed for the determination of oxytetracycline (OTC), tetracycline (TC), chlorotetracycline (CTC), doxycycline (DC), enrofloxacin (ENR), ciprofloxacin (CIP), sarafloxacin (SAR) and flumequine (FLU) residues in animal drinking water. This method was applied to animal drinking water. Solid-phase extraction (SPE) clean-up on an Oasis HLB cartridge allowed an extract suitable for liquid chromatographic analysis to be obtained. Chromatographic separation was carried out on a C18 analytical column, using gradient elution with 0.1% trifluoroacetic acid - acetonitrile - methanol at 30°C. The flow-rate was 0.7 mL/min and the eluate was analysed at 330 nm. The whole procedure was evaluated according to the requirements of the Commission Decision 2002/657/EC, determining specificity, decision limit (CCα), detection capacity (CCβ), limit of detection (LOD), limit of quantification (LOQ), precision and accuracy during validation of the method. The recoveries of TCs and FQs from spiked samples at the levels of 10, 100 and 1000 μg/L were higher than 82%. The developed method based on HPLC-DAD has been applied for the determination of four tetracyclines and four fluoroquinolones in animal drinking water samples.

Quinolines in clothing textiles--a source of human exposure and wastewater pollution?

PubMed

Luongo, Giovanna; Thorsén, Gunnar; Ostman, Conny

2014-05-01

A production process in which the use of various types of chemicals seems to be ubiquitous makes the textile industry a growing problem regarding both public health as well as the environment. Among several substances used at each stage, the present study focuses on the quinolines, a class of compounds involved in the manufacture of dyes, some of which are skin irritants and/or classified as probable human carcinogens. A method was developed for the determination of quinoline derivatives in textile materials comprising ultrasound-assisted solvent extraction, solid phase extraction cleanup, and final analysis by gas chromatography/mass spectrometry. Quinoline and ten quinoline derivatives were determined in 31 textile samples. The clothing samples, diverse in color, material, brand, country of manufacture, and price, and intended for a broad market, were purchased from different shops in Stockholm, Sweden. Quinoline, a possible human carcinogen, was found to be the most abundant compound present in almost all of the samples investigated, reaching a level of 1.9 mg in a single garment, and it was found that quinoline and its derivatives were mainly correlated to polyester material. This study points out the importance of screening textiles with nontarget analysis to investigate the presence of chemicals in an unbiased manner. Focus should be primarily on clothing worn close to the body.

Analytical method for the evaluation of the outdoor air contamination by emerging pollutants using tree leaves as bioindicators.

PubMed

Barroso, Pedro José; Martín, Julia; Santos, Juan Luis; Aparicio, Irene; Alonso, Esteban

2018-01-01

In this work, an analytical method, based on sonication-assisted extraction, clean-up by dispersive solid-phase extraction and determination by liquid chromatography-tandem mass spectrometry, has been developed and validated for the simultaneous determination of 15 emerging pollutants in leaves from four ornamental tree species. Target compounds include perfluorinated organic compounds, plasticizers, surfactants, brominated flame retardant, and preservatives. The method was optimized using Box-Behnken statistical experimental design with response surface methodology and validated in terms of recovery, accuracy, precision, and method detection and quantification limits. Quantification of target compounds was carried out using matrix-matched calibration curves. The highest recoveries were achieved for the perfluorinated organic compounds (mean values up to 87%) and preservatives (up to 88%). The lowest recoveries were achieved for plasticizers (51%) and brominated flame retardant (63%). Method detection and quantification limits were in the ranges 0.01-0.09 ng/g dry matter (dm) and 0.02-0.30 ng/g dm, respectively, for most of the target compounds. The method was successfully applied to the determination of the target compounds on leaves from four tree species used as urban ornamental trees (Citrus aurantium, Celtis australis, Platanus hispanica, and Jacaranda mimosifolia). Graphical abstract Analytical method for the biomonitorization of emerging pollutants in outdoor air.

Determination of cyflumetofen residue in water, soil, and fruits by modified quick, easy, cheap, effective, rugged, and safe method coupled to gas chromatography/tandem mass spectrometry.

PubMed

Li, Minmin; Liu, Xingang; Dong, Fengshou; Xu, Jun; Qin, Dongmei; Zheng, Yongquan

2012-10-01

A new, highly sensitive, and selective method was developed for the determination of the cyflumetofen residue in water, soil, and fruits by using gas chromatography quadruple mass spectrometry. The target compound was extracted using acetonitrile and then cleaned up using dispersive solid-phase extraction with primary and secondary amine and graphitized carbon black, and optionally by a freezing-out cleanup step. The matrix-matched standards gave satisfactory recoveries and relative standard deviation values in different matrices at three fortified levels (0.05, 0.5, and 1.0 mg kg(-1) ). The overall average recoveries for this method in water, soil, and all fruits matrix at three fortified levels ranged from 76.3 to 101.5% with relative standard deviations in the range of 1.2-11.8% (n = 5). The calculated limits of detection and quantification were typically below 0.005 and 0.015 μg kg(-1), which were much lower than the maximum residue levels established by Japanese Positive List. This study provides a theoretical basis for China to draw up maximum residue level and analytical method for cyflumetofen acaricide in different fruits. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simple and sensitive monitoring of β2-agonist residues in meat by liquid chromatography-tandem mass spectrometry using a QuEChERS with preconcentration as the sample treatment.

PubMed

Xiong, Lin; Gao, Ya-Qin; Li, Wei-Hong; Yang, Xiao-Lin; Shimo, Shimo Peter

2015-07-01

A liquid chromatography with tandem mass spectrometric detection (LC-MS/MS) method was established for the simultaneous determination of the levels of 10 β2-agonists in meat. The samples were extracted using an aqueous acidic solution and cleaned up using a Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) technique utilising a DVB-NVP-SO3Na sorbent synthesised in-house. First, the β2-agonist residues were extracted in an aqueous acidic solution, followed by matrix solid-phase dispersion for clean-up. The linearities of the method were R(2)=0.9925-0.9998, with RSDs of 2.7-15.3% and 73.7-103.5% recoveries. Very low limits of detection (LOD) and quantitation (LOQ) of 0.2-0.9 μg/kg and 0.8-3.2 μg/kg, respectively, were achieved for spiked meat. The values obtained were lower than the maximum residue limits (MRLs) established by the EU and China. These results clearly demonstrate the feasibility of the proposed approach. The evaluated method provided reliable screening, quantification and identification of 10 β2-agonists in meat. Copyright © 2015 Elsevier Ltd. All rights reserved.

Development of a new multi-residue laser diode thermal desorption atmospheric pressure chemical ionization tandem mass spectrometry method for the detection and quantification of pesticides and pharmaceuticals in wastewater samples.

PubMed

Boisvert, Michel; Fayad, Paul B; Sauvé, Sébastien

2012-11-19

A new solid phase extraction (SPE) method coupled to a high throughput sample analysis technique was developed for the simultaneous determination of nine selected emerging contaminants in wastewater (atrazine, desethylatrazine, 17β-estradiol, ethynylestradiol, norethindrone, caffeine, carbamazepine, diclofenac and sulfamethoxazole). We specifically included pharmaceutical compounds from multiple therapeutic classes, as well as pesticides. Sample pre-concentration and clean-up was performed using a mixed-mode SPE cartridge (Strata ABW) having both cation and anion exchange properties, followed by analysis by laser diode thermal desorption atmospheric pressure chemical ionization coupled to tandem mass spectrometry (LDTD-APCI-MS/MS). The LDTD interface is a new high-throughput sample introduction method, which reduces total analysis time to less than 15s per sample as compared to minutes with traditional liquid-chromatography coupled to tandem mass spectrometry (LC-MS/MS). Several SPE parameters were evaluated in order to optimize recovery efficiencies when extracting analytes from wastewater, such as the nature of the stationary phase, the loading flow rate, the extraction pH, the volume and composition of the washing solution and the initial sample volume. The method was successfully applied to real wastewater samples from the primary sedimentation tank of a municipal wastewater treatment plant. Recoveries of target compounds from wastewater ranged from 78% to 106%, the limit of detection ranged from 30 to 122ng L(-1) while the limit of quantification ranged from 90 to 370ng L(-1). Calibration curves in the wastewater matrix showed good linearity (R(2)≥0.991) for all target analytes and the intraday and interday coefficient of variation was below 15%, reflecting a good precision. Copyright © 2012 Elsevier B.V. All rights reserved.

Use of ammonium formate in QuEChERS for high-throughput analysis of pesticides in food by fast, low-pressure gas chromatography and liquid chromatography tandem mass spectrometry.

PubMed

González-Curbelo, Miguel Ángel; Lehotay, Steven J; Hernández-Borges, Javier; Rodríguez-Delgado, Miguel Ángel

2014-09-05

The "quick, easy, cheap, effective, rugged, and safe" (QuEChERS) approach to sample preparation is widely applied in pesticide residue analysis, but the use of magnesium sulfate and other nonvolatile compounds for salting out in the method is not ideal for mass spectrometry. In this study, we developed and evaluated three new different versions of the QuEChERS method using more volatile salts (ammonium chloride and ammonium formate and acetate buffers) to induce phase separation and extraction of 43 representative pesticide analytes of different classes. Fast low-pressure gas chromatography tandem mass spectrometry (LPGC-MS/MS) and liquid chromatography (LC)-MS/MS were used for analysis. The QuEChERS AOAC Official Method 2007.01 was also tested for comparison purposes. Of the studied methods, formate buffering using 7.5g of ammonium formate and 15mL of 5% (v/v) formic acid in acetonitrile for the extraction of 15g of sample (5g for wheat grain) provided the best performance and practical considerations. Method validation was carried out with and without the use of dispersive solid-phase extraction for cleanup, and no significant differences were observed for the majority of pesticides. The method was demonstrated in quantitative analysis for GC- and LC-amenable pesticides in 4 representative food matrices (apple, lemon, lettuce, and wheat grain). With the typical exceptions of certain pH-dependent and labile pesticides, 90-110% recoveries and <10% RSD were obtained. Detection limits were mostly <5ng/g, which met the general need to determine pesticide concentrations as low as 10ng/g for monitoring purposes in food applications. Published by Elsevier B.V.

An updated ciguatoxin extraction method and silica cleanup for use with HPLC-MS/MS for the analysis of P-CTX-1, PCTX-2 and P-CTX-3.

PubMed

Meyer, Lauren; Carter, Steve; Capper, Angela

2015-12-15

Ciguatera fish poisoning is a debilitating human neuro-intoxication caused by consumption of tropical marine organisms, contaminated with bioaccumulated ciguatoxins (CTXs). The growing number of cases coupled with the high toxicity of CTXs makes their reliable detection and quantification of paramount importance. Three commonly occurring ciguatoxins, P-CTX-1, 2 and 3 from five different ciguatoxic Spanish mackerel (Scomberomorus commerson), were used to assess the effectiveness of different extraction techniques: homogenization (high powered blending vs. ultrasonication); C-18 column sizes (500 mg vs. 900 mg); and a novel HILIC SPE cleanup. Despite minor differences, blending and sonication proved equally effective. Larger 900 mg columns offered a greater extraction efficiency, increasing detected P-CTX-1 by 37% (P < 0.001). The newly adapted cleanup was highly effective at reducing co-eluting phospholipids thereby reducing matrix effects and increasing detectable CTXs by HPLC-MS/MS. Silica cleanup extraction efficiencies were also compared between the highly effective and validated ciguatoxin rapid extraction method (CREM) and current best practice extraction method employed by Queensland Health (QH). Overall, the QH protocol proved more effective, especially when paired with the newly adapted cleanup, as this increased the amount of extracted P-CTX-1 by 46% (P < 0.01), P-CTX-2 by 10% and P-CTX-3 by 71% (P = 0.001). This study suggests the QH protocol utilizing a 900 mg C-18 column and newly adapted HILIC SPE cleanup was most effective at extracting P-CTX-1, -2, -3. Specifically P-CTX-1, the primary ciguatoxin congener of concern due to its extremely high potency and an ability to cause CFP at 0.1 μg/kg following consumption of carnivorous fish flesh. Despite being more time intensive (an additional 85 min per batch of 12 samples), this will be especially effective for assessing lower toxin burdens, which may be near the limit of detection. Copyright © 2015 Elsevier Ltd. All rights reserved.

Optimization of cloud point extraction and solid phase extraction methods for speciation of arsenic in natural water using multivariate technique.

PubMed

Baig, Jameel A; Kazi, Tasneem G; Shah, Abdul Q; Arain, Mohammad B; Afridi, Hassan I; Kandhro, Ghulam A; Khan, Sumaira

2009-09-28

The simple and rapid pre-concentration techniques viz. cloud point extraction (CPE) and solid phase extraction (SPE) were applied for the determination of As(3+) and total inorganic arsenic (iAs) in surface and ground water samples. The As(3+) was formed complex with ammonium pyrrolidinedithiocarbamate (APDC) and extracted by surfactant-rich phases in the non-ionic surfactant Triton X-114, after centrifugation the surfactant-rich phase was diluted with 0.1 mol L(-1) HNO(3) in methanol. While total iAs in water samples was adsorbed on titanium dioxide (TiO(2)); after centrifugation, the solid phase was prepared to be slurry for determination. The extracted As species were determined by electrothermal atomic absorption spectrometry. The multivariate strategy was applied to estimate the optimum values of experimental factors for the recovery of As(3+) and total iAs by CPE and SPE. The standard addition method was used to validate the optimized methods. The obtained result showed sufficient recoveries for As(3+) and iAs (>98.0%). The concentration factor in both cases was found to be 40.

Reactor water cleanup system

DOEpatents

Gluntz, D.M.; Taft, W.E.

1994-12-20

A reactor water cleanup system includes a reactor pressure vessel containing a reactor core submerged in reactor water. First and second parallel cleanup trains are provided for extracting portions of the reactor water from the pressure vessel, cleaning the extracted water, and returning the cleaned water to the pressure vessel. Each of the cleanup trains includes a heat exchanger for cooling the reactor water, and a cleaner for cleaning the cooled reactor water. A return line is disposed between the cleaner and the pressure vessel for channeling the cleaned water thereto in a first mode of operation. A portion of the cooled water is bypassed around the cleaner during a second mode of operation and returned through the pressure vessel for shutdown cooling. 1 figure.

SIMPLE METHOD FOR ESTIMATING POLYCHLORINATED BIPHENYL CONCENTRATIONS ON SOILS AND SEDIMENTS USING SUBCRITICAL WATER EXTRACTION COUPLED WITH SOLID-PHASE MICROEXTRACTION. (R825368)

EPA Science Inventory

A rapid method for estimating polychlorinated biphenyl (PCB) concentrations in contaminated soils and sediments has been developed by coupling static subcritical water extraction with solid-phase microextraction (SPME). Soil, water, and internal standards are placed in a seale...

EPA Method 525.3 - Determination of Semivolatile Organic Chemicals in Drinking Water by Solid Phase Extraction and Capillary Column Gas Chromatography/Mass Spectrometry (GC/MS)

EPA Science Inventory

Method 525.3 is an analytical method that uses solid phase extraction (SPE) and gas chromatography/mass spectrometry (GC/MS) for the identification and quantitation of 125 selected semi-volatile organic chemicals in drinking water.

QUANTIFICATION OF 2,4-D ON SOLID-PHASE EXPOSURE SAMPLING MEDIA BY LC/MS/MS

EPA Science Inventory

Three types of solid phase chemical exposure sampling media: cellulose, polyurethane foam (PUF) and XAD-2, were analyzed for 2,4-D and the amine salts of 2,4-D. Individual samples were extracted into acidified methanol and the extracts were analyzed via LC/MS/MS using electrospra...

Solid phase extraction for the speciation and preconcentration of inorganic selenium in water samples: a review.

PubMed

Herrero Latorre, C; Barciela García, J; García Martín, S; Peña Crecente, R M

2013-12-04

Selenium is an essential element for the normal cellular function of living organisms. However, selenium is toxic at concentrations of only three to five times higher than the essential concentration. The inorganic forms (mainly selenite and selenate) present in environmental water generally exhibit higher toxicity (up to 40 times) than organic forms. Therefore, the determination of low levels of different inorganic selenium species in water is an analytical challenge. Solid-phase extraction has been used as a separation and/or preconcentration technique prior to the determination of selenium species due to the need for accurate measurements for Se species in water at extremely low levels. The present paper provides a critical review of the published methods for inorganic selenium speciation in water samples using solid phase extraction as a preconcentration procedure. On the basis of more than 75 references, the different speciation strategies used for this task have been highlighted and classified. The solid-phase extraction sorbents and the performance and analytical characteristics of the developed methods for Se speciation are also discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

Split Flow Online Solid-Phase Extraction Coupled with Inductively Coupled Plasma Mass Spectrometry System for One-Shot Data Acquisition of Quantification and Recovery Efficiency.

PubMed

Furukawa, Makoto; Takagai, Yoshitaka

2016-10-04

Online solid-phase extraction (SPE) coupled with inductively coupled plasma mass spectrometry (ICPMS) is a useful tool in automatic sequential analysis. However, it cannot simultaneously quantify the analytical targets and their recovery percentages (R%) in one-shot samples. We propose a system that simultaneously acquires both data in a single sample injection. The main flowline of the online solid-phase extraction is divided into main and split flows. The split flow line (i.e., bypass line), which circumvents the SPE column, was placed on the main flow line. Under program-controlled switching of the automatic valve, the ICPMS sequentially measures the targets in a sample before and after column preconcentration and determines the target concentrations and the R% on the SPE column. This paper describes the system development and two demonstrations to exhibit the analytical significance, i.e., the ultratrace amounts of radioactive strontium ( 90 Sr) using commercial Sr-trap resin and multielement adsorbability on the SPE column. This system is applicable to other flow analyses and detectors in online solid phase extraction.

A simplified radiometabolite analysis procedure for PET radioligands using a solid phase extraction with micellar medium.

PubMed

Nakao, Ryuji; Halldin, Christer

2013-07-01

A solid phase extraction method has been developed for simple and high-speed direct determination of PET radioligands in plasma. This methodology makes use of a micellar medium and a solid-phase extraction cartridge for displacement of plasma protein bound radioligand and separation of PET radioligands from their radiometabolites without significant preparation. The plasma samples taken from monkey or human during PET measurements were mixed with a micellar eluent containing an anionic surfactant sodium dodecyl sulphate and loaded onto SPE cartridges. The amount of radioactivity corresponding to parent radioligand (retained on the cartridge) and its radioactive metabolites (eluted with micellar eluent) was measured. Under the optimized conditions, excellent separation of target PET radioligands from their radiometabolites was achieved with a single elution and short run-time of 1 min. This method was successfully applied to study the metabolism for (11)C-labelled radioligands in human or monkey plasma. The amount of parent PET radioligands estimated by micellar solid phase extraction strongly corresponded with that determined by radio-LC. The improved throughput permitted the analysis of a large number of plasma samples (up to 13 samples per one PET study) for accurate estimation of metabolite-corrected input function during quantitative PET imaging studies. Solid phase extraction together with micellar medium is fast, sensitive and easy to use, and therefore it is an attractive alternative method to determine relative composition of PET radioligands in plasma. Copyright © 2013 Elsevier Inc. All rights reserved.

Fully automatic method for the determination of fat soluble vitamins and vitamin D metabolites in serum.

PubMed

Mata-Granados, J M; Quesada Gómez, J M; Luque de Castro, M D

2009-05-01

Fat soluble vitamins and vitamin D metabolites are key compounds in bone metabolism. Unfortunately, variability among 25(OH)D assays limits clinician ability to monitor vitamin D status, supplementation, and toxicity. 0.5 ml serum was mixed with 0.5 ml 60% acetonitrile 150 mM sodium dodecyl sulfate, vortexed for 30 s and injected into an automatic solid-phase extraction (SPE) system for cleanup-preconcentration, then on-line transferred to a reversed-phase analytical column by a 15% methanol-acetonitrile mobile phase at 1.0 ml/min for individual separation of the target analytes. Ultraviolet detection was performed at 265 nm, 325 nm and 292 for vitamin D metabolites, vitamin A and alpha- and delta-tocopherols, respectively. Detection limits were between 0.0015 and 0.26 microg/ml for the target compounds, the precision (expressed as relative standard deviation) between 0.83 and 3.6% for repeatability and between 1.8 and 4.62% for within laboratory reproducibility. Recoveries between 97-100.2% and 95-99% were obtained for low and high concentrations of the target analytes in serum. The total analysis time was 20 min. The on-line coupling of SPE-HPLC endows the proposed method with reliability, robustness, and user unattendance, making it a useful tool for high-throughput analysis in clinical and research laboratories.

New Approaches in Soil Organic Matter Fluorescence; A Solid Phase Fluorescence Approach

NASA Astrophysics Data System (ADS)

Bowman, M. M.; Sanclements, M.; McKnight, D. M.

2017-12-01

Fluorescence spectroscopy is a well-established technique to investigate the composition of organic matter in aquatic systems and is increasingly applied to soil organic matter (SOM). Current methods require that SOM be extracted into a liquid prior to analysis by fluorescence spectroscopy. Soil extractions introduce an additional layer of complexity as the composition of the organic matter dissolved into solution varies based upon the selected extractant. Water is one of the most commonly used extractant, but only extracts the water-soluble fraction of the SOM with the insoluble soil organic matter fluorescence remaining in the soil matrix. We propose the use of solid phase fluorescence on whole soils as a potential tool to look at the composition of organic matter without the extraction bias and gain a more complete understand of the potential for fluorescence as a tool in terrestrial studies. To date, the limited applications of solid phase fluorescence have ranged from food and agriculture to pharmaceutical with no clearly defined methods and limitations available. We are aware of no other studies that use solid phase fluorescence and thus no clear methods to look at SOM across a diverse set of soil types and ecosystems. With this new approach to fluorescence spectroscopy there are new challenges, such as blank correction, inner filter effect corrections, and sample preparation. This work outlines a novel method for analyzing soil organic matter using solid phase fluorescence across a wide range of soils collected from the National Ecological Observatory Network (NEON) eco-domains. This method has shown that organic matter content in soils must be diluted to 2% to reduce backscattering and oversaturation of the detector in forested soils. In mineral horizons (A) there is observed quenching of the humic-like organic matter, which is likely a result of organo-mineral complexation. Finally, we present preliminary comparisons between solid and liquid phase fluorescence, which provide new insights into fluorescence studies in terrestrial systems.

Improvements in the analytical methodology for the residue determination of the herbicide glyphosate in soils by liquid chromatography coupled to mass spectrometry.

PubMed

Botero-Coy, A M; Ibáñez, M; Sancho, J V; Hernández, F

2013-05-31

The determination of glyphosate (GLY) in soils is of great interest due to the widespread use of this herbicide and the need of assessing its impact on the soil/water environment. However, its residue determination is very problematic especially in soils with high organic matter content, where strong interferences are normally observed, and because of the particular physico-chemical characteristics of this polar/ionic herbicide. In the present work, we have improved previous LC-MS/MS analytical methodology reported for GLY and its main metabolite AMPA in order to be applied to "difficult" soils, like those commonly found in South-America, where this herbicide is extensively used in large areas devoted to soya or maize, among other crops. The method is based on derivatization with FMOC followed by LC-MS/MS analysis, using triple quadrupole. After extraction with potassium hydroxide, a combination of extract dilution, adjustment to appropriate pH, and solid phase extraction (SPE) clean-up was applied to minimize the strong interferences observed. Despite the clean-up performed, the use of isotope labelled glyphosate as internal standard (ILIS) was necessary for the correction of matrix effects and to compensate for any error occurring during sample processing. The analytical methodology was satisfactorily validated in four soils from Colombia and Argentina fortified at 0.5 and 5mg/kg. In contrast to most LC-MS/MS methods, where the acquisition of two transitions is recommended, monitoring all available transitions was required for confirmation of positive samples, as some of them were interfered by unknown soil components. This was observed not only for GLY and AMPA but also for the ILIS. Analysis by QTOF MS was useful to confirm the presence of interferent compounds that shared the same nominal mass of analytes as well as some of their main product ions. Therefore, the selection of specific transitions was crucial to avoid interferences. The methodology developed was applied to the analysis of 26 soils from different areas of Colombia and Argentina, and the method robustness was demonstrated by analysis of quality control samples along 4 months. Copyright © 2012 Elsevier B.V. All rights reserved.

Laboratory study of the response of select insecticides to toxicity identification evaluation procedures

USGS Publications Warehouse

Kuivila, Kathryn; Crepeau, Kathryn L.

1999-01-01

A laboratory study was used to evaluate the response of select insecticides to toxicity identification evaluation procedures. Fourteen insecticides, one degradation product, and one synergist were spiked into organic-grade water and carried through toxicity identification evaluation procedures. Concentrations of each compound were analyzed by gas chromatography/mass spectrometry. During Phase I, the water sample was pumped through a C-8 solid-phase extraction cartridge and then eluted with methanol. Dimethoate was not removed by the extraction, but remained in the rinsate. In contrast, permethrin was removed by the extraction, but was not recovered by the methanol elution, and 80 percent of the permethrin remained on the cartridge, teflon tubing, and glassware. Chlorpyrifos also was not recovered completely with the methanol elution (only 62 percent was recovered). The other insecticides were extracted by C-8 solid-phase extraction cartridge and recovered by elution with methanol (80 percent or greater). During Phase II, a new spiked water sample was extracted by C-8 solid-phase extraction cartridge and then eluted with varying concentrations of methanol and water into different fractions. Each methanol:water fraction was analyzed for the added compounds. Most of the insecticides eluted in two fractions, with concentrations of 10 percent or greater. The largest number of insecticides eluted in the 75 percent methanol:water fraction.

Determination of fatty acid ethyl esters (FAEE) and ethyl glucuronide (EtG) in hair: a promising way for retrospective detection of alcohol abuse during pregnancy?

PubMed

Pragst, Fritz; Yegles, Michel

2008-04-01

The retrospective detection of alcohol consumption during pregnancy is an important part of the diagnosis of the fetal alcohol syndrome. A promising way to solve this problem can be the determination of fatty acid ethyl esters (FAEE) or/and ethyl glucuronide (EtG) in hair of the mothers. In this article, the present state in analytical determination and interpretation of FAEE and EtG concentrations in hair are reviewed. Both FAEE and EtG are minor metabolites of ethanol and as direct alcohol markers very specific for alcohol. They are durably deposited in hair, which enables taking advantage of the long diagnostic time window of this sample material. In the last years, specific and sensitive methods for determination of both alcohol markers in hair were developed. Headspace solid phase microextraction in combination with gas chromatography-mass spectroscopy after hair extraction with an n-heptane/dimethylsulfoxide mixture proved to be a favorable technique for determination of four characteristic FAEE (ethyl myristate, ethyl palmitate, ethyl oleate, and ethyl stearate). EtG is extracted from hair by water and analyzed either by gas chromatography-mass spectroscopy with negative chemical ionization after cleanup with solid phase extraction and derivatization with pentafluoropropionic anhydride or by liquid chromatography-mass spectroscopy-mass spectroscopy. The detection limits of the single FAEE as well as of EtG are in the range of 1 to 10 pg/mg. FAEE as well as EtG were determined in a larger number of hair samples of teetotalers, social drinkers, patients in alcohol withdrawal treatment, and death cases with previous known heavy drinking. From the results, the following criteria were derived: strict abstinence is excluded or improbable at C FAEE >0.2 ng/mg or C EtG >7 pg/mg. Moderate social drinkers should have C FAEE <0.5 ng/mg and C EtG <25 pg/mg; above these values, alcohol abuse is probable. Until now, there has been no evaluation in context of FAS diagnosis; however, a successful application for this purpose can be expected from the good experience in driving ability examination.

Platform construction and extraction mechanism study of magnetic mixed hemimicelles solid-phase extraction

PubMed Central

Xiao, Deli; Zhang, Chan; He, Jia; Zeng, Rong; Chen, Rong; He, Hua

2016-01-01

Simple, accurate and high-throughput pretreatment method would facilitate large-scale studies of trace analysis in complex samples. Magnetic mixed hemimicelles solid-phase extraction has the power to become a key pretreatment method in biological, environmental and clinical research. However, lacking of experimental predictability and unsharpness of extraction mechanism limit the development of this promising method. Herein, this work tries to establish theoretical-based experimental designs for extraction of trace analytes from complex samples using magnetic mixed hemimicelles solid-phase extraction. We selected three categories and six sub-types of compounds for systematic comparative study of extraction mechanism, and comprehensively illustrated the roles of different force (hydrophobic interaction, π-π stacking interactions, hydrogen-bonding interaction, electrostatic interaction) for the first time. What’s more, the application guidelines for supporting materials, surfactants and sample matrix were also summarized. The extraction mechanism and platform established in the study render its future promising for foreseeable and efficient pretreatment under theoretical based experimental design for trace analytes from environmental, biological and clinical samples. PMID:27924944

Solid-phase extraction versus matrix solid-phase dispersion: Application to white grapes.

PubMed

Dopico-García, M S; Valentão, P; Jagodziñska, A; Klepczyñska, J; Guerra, L; Andrade, P B; Seabra, R M

2007-11-15

The use of matrix solid-phase dispersion (MSPD) was tested to, separately, extract phenolic compounds and organic acids from white grapes. This method was compared with a more conventional analytical method previously developed that combines solid liquid extraction (SL) to simultaneously extract phenolic compounds and organic acids followed by a solid-phase extraction (SPE) to separate the two types of compounds. Although the results were qualitatively similar for both techniques, the levels of extracted compounds were in general quite lower on using MSPD, especially for organic acids. Therefore, SL-SPE method was preferred to analyse white "Vinho Verde" grapes. Twenty samples of 10 different varieties (Alvarinho, Avesso, Asal-Branco, Batoca, Douradinha, Esganoso de Castelo Paiva, Loureiro, Pedernã, Rabigato and Trajadura) from four different locations in Minho (Portugal) were analysed in order to study the effects of variety and origin on the profile of the above mentioned compounds. Principal component analysis (PCA) was applied separately to establish the main sources of variability present in the data sets for phenolic compounds, organic acids and for the global data. PCA of phenolic compounds accounted for the highest variability (77.9%) with two PCs, enabling characterization of the varieties of samples according to their higher content in flavonol derivatives or epicatechin. Additionally, a strong effect of sample origin was observed. Stepwise linear discriminant analysis (SLDA) was used for differentiation of grapes according to the origin and variety, resulting in a correct classification of 100 and 70%, respectively.

Preparation and characterization of molecularly imprinted polymer for di(2-ethylhexyl) phthalate: application to sample clean-up prior to gas chromatographic determination.

PubMed

Shaikh, Huma; Memon, Najma; Khan, Hamayun; Bhanger, M I; Nizamani, S M

2012-07-20

The molecularly imprinted polymer (MIP) selective for di(2-ethylhexyl) phthalate (DEHP) an environmental endocrine disruptor was prepared by suspension polymerization using methacrylamide as functional monomer and N,N'-methylene-bis-acrylamide as cross-linker. The imprinted polymer was employed for solid-phase extraction of DEHP from water samples of environmental importance and characterized by FT-IR and SEM. The adsorption properties of the imprinted polymer were demonstrated by equilibrium rebinding experiments, Pseudo-second-order kinetic model, Sips isotherm and Scatchard analysis. The reusability of MIP was checked for at least six repeated batch adsorption cycles and the results showed almost no deterioration in the adsorption capacity. The competitive recognition studies were performed with DEHP and structurally similar compounds; dimethyl phthalate (DMP), diethyl phthalate (DEP), and dibutyl phthalate (DBP). The imprinting factor (IF) of DEHP was found to be 12.86 which was much higher than the imprinting factors (IF) of other phthalates. A method constituted by molecularly imprinted solid-phase extraction (MISPE) with GC-FID was developed for DEHP analysis in water samples under very simple conditions. Sample loading and desorption conditions were also optimized. The MISPE method's linearity ranged from 0.035 to 3.0 μg ml⁻¹ with r² = 0.9998. Intra-assay, interassay precision and accuracy ranged from 0.0168% to 1.017%, 1.130% to 4.799% and 94.98% to 99.35%, respectively. The LOD and LOQ were found to be 0.011 and 0.035 μg ml⁻¹, respectively. Synthesized MIP was employed in MISPE for cleaning up the spiked river water samples prior to gas chromatographic analysis. The river samples were found to contain DEHP in the range of 1.4 × 10⁻³ to 0.349 μg ml⁻¹. Copyright © 2012 Elsevier B.V. All rights reserved.

Pressure-driven mesofluidic platform integrating automated on-chip renewable micro-solid-phase extraction for ultrasensitive determination of waterborne inorganic mercury.

PubMed

Portugal, Lindomar A; Laglera, Luis M; Anthemidis, Aristidis N; Ferreira, Sérgio L C; Miró, Manuel

2013-06-15

A dedicated pressure-driven mesofluidic platform incorporating on-chip sample clean-up and analyte preconcentration is herein reported for expedient determination of trace level concentrations of waterborne inorganic mercury. Capitalizing upon the Lab-on-a-Valve (LOV) concept, the mesofluidic device integrates on-chip micro-solid phase extraction (μSPE) in automatic disposable mode followed by chemical vapor generation and gas-liquid separation prior to in-line atomic fluorescence spectrometric detection. In contrast to prevailing chelating sorbents for Hg(II), bare poly(divinylbenzene-N-vinylpyrrolidone) copolymer sorptive beads were resorted to efficient uptake of Hg(II) in hydrochloric acid milieu (pH=2.3) without the need for metal derivatization nor pH adjustment of prior acidified water samples for preservation to near-neutral conditions. Experimental variables influencing the sorptive uptake and retrieval of target species and the evolvement of elemental mercury within the miniaturized integrated reaction chamber/gas-liquid separator were investigated in detail. Using merely <10 mg of sorbent, the limits of detection and quantification at the 3s(blank) and 10s(blank) levels, respectively, for a sample volume of 3 mL were 12 and 42 ng L(-1) Hg(II) with a dynamic range extending up to 5.0 μg L(-1). The proposed mesofluidic platform copes with the requirements of regulatory bodies (US-EPA, WHO, EU-Commission) for drinking water quality and surface waters that endorse maximum allowed concentrations of mercury spanning from 0.07 to 6.0 μg L(-1). Demonstrated with the analysis of aqueous samples of varying matrix complexity, the LOV approach afforded reliable results with relative recoveries of 86-107% and intermediate precision down to 9% in the renewable μSPE format. Copyright © 2013 Elsevier B.V. All rights reserved.

Graphene-encapsulated silica as matrix solid-phase dispersion extraction sorbents for the analysis of poly-methoxylated flavonoids in the leaves of Murraya panaculata (L.) Jack.

PubMed

Sun, Ting; Li, Xuwen; Yang, Jie; Li, Lanjie; Jin, Yongri; Shi, Xiaolei

2015-06-01

In this study, graphene-encapsulated silica was synthesized by a hydrothermal reduction strategy. The presence of silica in graphene was identified by Fourier-transform infrared spectrometry, X-ray diffraction and scanning electron microscopy. The graphene-encapsulated silica subsequently was used as adsorbent for matrix solid-phase dispersion extraction of poly-methoxylated flavonoids from the dried leaves of Murraya panaculata (L.) Jack. Compared with the other adsorbents (graphene, silica gel, C18 silica, neutral alumina, diatomaceous earth) and without any adsorbents, better results were obtained. Then a method for analysis of poly-methoxylated flavonoids was established by coupling matrix solid-phase dispersion extraction with ultra high performance liquid chromatography and UV detection. Compared with reflux extraction and ultrasonic extraction, the proposed method is quicker, more efficient and more environmental protection. Less than 10 min is needed from extraction to detection. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimized HPLC method for analysis of polar and nonpolar heterocyclic amines in cooked meat products.

PubMed

Gibis, Monika

2009-01-01

A simple, precise, and specific column high-performance liquid chromatographic (HPLC) method with UV absorption diode array and fluorescence detection has been developed by optimizing a previously described method for the simultaneous quantification of 15 polar and nonpolar heterocyclic amines (HAs) in fried meat products. The HPLC determination could be improved due to the application of a silica-based reversed-phase column with octadecyl groups (TSK-gel Super ODS) and a particle size of 2 microm. The separation of HAs in the complex meat matrix was performed with a 21 min mobile phase gradient. The method was validated for instrumental precision, repeatability, and selectivity and compared with a previously published method. After liquid adsorption of the basic sample mixture on diatomaceous earth, HAs were extracted with ethyl acetate. For cleanup, solid-phase extraction (silica propylsulfonic acid and octadecyl cartridges) and different washing steps were applied. Both nonpolar and polar HAs were determined in one fraction. The calibration curves of all HAs were linear for the applied detection system (correlation coefficient = 0.990-0.995). The recoveries, with the exception of 3-amino-1-methyl-5H-pyrido [4,3-b]indole (Trp-P-2), were between 42 and 98% from meat samples spiked in a range of 1.5 to 3.3 ng/g for fluorescence-active and 4.3 to 8 ng/g for UV-active HAs. For quantification of HAs, the standard addition method was used for adjustment of different characteristics of HAs in the extraction. In fried meat samples (chicken breast and beef patties), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MelQx), 2-amino-3,4,8-trimethylimidazo[4,5-f] quinoxaline(4,8-DiMelQx), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), norharmane, and harmane were found in a concentration range of 0.02 to 14.3 ng/g.

Analysis of glyphosate and aminomethylphosphonic acid in leaves from Coffea arabica using high performance liquid chromatography with quadrupole mass spectrometry detection.

PubMed

Schrübbers, Lars C; Masís-Mora, Mario; Rojas, Elizabeth Carazo; Valverde, Bernal E; Christensen, Jan H; Cedergreen, Nina

2016-01-01

Glyphosate is a commonly applied herbicide in coffee plantations. Because of its non-selective mode of action it can damage the crop exposed through spray drift. Therefore, it is of interest to study glyphosate fate in coffee plants. The aim of this study was to develop an analytical method for accurate and precise quantification of glyphosate and its main metabolite aminomethylphosphonic acid (AMPA) at trace levels in coffee leaves using liquid chromatography with single-quadrupole mass spectrometry detection. The method is based on a two-step solid phase extraction (SPE) with an intermediate derivatization reaction using 9-fluorenylmethylchloroformate (FMOC). An isotope dilution method was used to account for matrix effects and to enhance the confidence in analyte identification. The limit of quantification (LOQ) for glyphosate and AMPA in coffee leaves was 41 and 111 μg kg(-1) dry weight, respectively. For the method optimization a design of experiments (DOE) approach was used. The sample clean-up procedure can be simplified for the analysis of less challenging matrices, for laboratories having a tandem mass spectrometry detector and for cases in which quantification limits above 0.1 mg kg(-1) are acceptable, which is often the case for glyphosate. The method is robust, possesses high identification confidence, while being suitable for most commercial and academic laboratories. All leaf samples from five coffee fields analyzed (n=21) contained glyphosate, while AMPA was absent. The simplified clean-up procedure was successfully validated for coffee leaves, rice, black beans and river water. Copyright © 2015 Elsevier B.V. All rights reserved.

Occurrence of pharmaceutical compounds in wastewater process streams in Dublin, Ireland.

PubMed

Lacey, Clair; Basha, Shaik; Morrissey, Anne; Tobin, John M

2012-01-01

The aim of this work is to establish baseline levels of pharmaceuticals in three wastewater treatment plant (WWTP) streams in the greater Dublin region to assess the removal efficiency of the selected WWTPs and to investigate the existence of any seasonal variability. Twenty compounds including several classes of antibiotics, acidic and basic pharmaceuticals, and prescribed medications were selected for investigation using a combination of membrane filtration, solid phase extraction (SPE) cleanup, and liquid chromatography-electrospray ionization tandem mass spectrometry. Fourteen of the selected compounds were found in the samples. Increased effluent concentrations, compared to influent concentrations, for a number of compounds (carbamazepine, clotrimazole, propranolol, nimesulide, furosemide, mefenamic acid, diclofenac, metoprolol, and gemfibrozil) were observed. The detected concentrations were generally below toxicity levels and based on current knowledge are unlikely to pose any threat to aquatic species. Mefenamic acid concentrations detected in both Leixlip and Swords effluents may potentially exert ecotoxicological effects with maximum risk quotients (i.e., ratio of predicted exposure concentration to predicted no effect concentration) of 4.04 and 1.33, respectively.

Discovery and structural elucidation of the illegal azo dye Basic Red 46 in sumac spice.

PubMed

Ruf, J; Walter, P; Kandler, H; Kaufmann, A

2012-01-01

An unknown red dye was discovered in a sumac spice sample during routine analysis for Sudan dyes. LC-DAD and LC-MS/MS did not reveal the identity of the red substance. Nevertheless, using LC-high-resolution MS and isotope ratio comparisons the structure was identified as Basic Red 46. The identity of the dye was further confirmed by comparison with a commercial hair-staining product and two textile dye formulations containing Basic Red 46. Analogous to the Sudan dyes, Basic Red 46 is an azo dye. However, some of the sample clean-up methodology utilised for the analysis of Sudan dyes in food prevents its successful detection. In contrast to the Sudan dyes, Basic Red 46 is a cation. Its cationic properties make it bind strongly to gel permeation columns and silica solid-phase extraction cartridges and prevent elution with standard eluents. This is the first report of Basic Red 46 in food. The structure elucidation of this compound as well as the disadvantages of analytical methods focusing on a narrow group of targeted analytes are discussed.

Analytical study of azadirachtin and 3-tigloylazadirachtol residues in foliage and phloem of hardwood tree species by liquid chromatography-electrospray mass spectrometry.

PubMed

Grimalt, Susana; Thompson, Dean G; Coppens, Melanie; Chartrand, Derek T; Shorney, Thomas; Meating, Joe; Scarr, Taylor

2011-08-10

A rapid and sensitive LC-ESI-MS method has been developed and validated for the quantitation of azadirachtin and 3-tigloylazadirachtol in deciduous tree matrices. The method involves automated extraction and simultaneous cleanup using an accelerated solvent technique with the matrix dispersed in solid phase over a layer of primary-secondary amine silica. The limits of quantification were 0.02 mg/kg for all matrices with the exception of Norway maple foliage (0.05 mg/kg). Validation at three levels (0.02, 0.1, and 1 mg/kg), demonstrated satisfactory recoveries (71-103%) with relative standard deviation <20%. Two in-source fragment ions were used for confirmation at levels above 0.1 mg/kg. Over a period of several months, quality control analyses showed the technique to be robust and effective in tracking the fate of these natural botanical insecticides following systemic injection into various tree species for control of invasive insect pest species such as the emerald ash borer and Asian longhorned beetle.

Stability of catechins in green tea nutraceutical products: application of solid phase extraction-thin layer chromatography densitometry.

PubMed

Abd-Elsalam, Heba-Alla H; Al-Ghobashy, Medhat A; Zaazaa, Hala E; Ibrahim, Mohamed A

2014-08-01

Epigallocatechin gallate (EGCG) is a powerful antioxidant and commonly used nutraceutical. Accelerated stability of EGCG in tablet formulations was investigated. LLE and SPE were employed for sample clean-up and enrichment of EGCG over caffeine. Samples were analysed after spiking with fixed concentration of gallic acid (GA), in order to verify reproducibility of analysis. A TLC-densitometric assay was developed and validated for determination of % loss EGCG. EGCG, GA and caffeine were resolved with Rf values 0.54, 0.69 and 0.80, respectively. LC-MS/MS was used to verify identity and purity of the EGCG band. Determination was carried out over a concentration range of 0.50-5.00μg/band and 0.20-2.40μg/band for GA and caffeine, respectively. Results showed significant reduction in EGCG content after one, three and six months: 24.00%, 28.00% and 52.00% respectively. Results continue to demonstrate that stability of nutraceutical products should be investigated in-depth using industry-oriented protocols before granting marketing authorisation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Use of Solid Phase Extraction in the Biochemistry Laboratory to Separate Different Lipids

ERIC Educational Resources Information Center

Flurkey, William H.

2005-01-01

Solid-phase extraction (SPE) was used to demonstrate how various lipids and lipid classes could be separated in a biochemistry laboratory setting. Three different SPE methods were chosen on their ability to separate a lipid mixture, consisting of a combination of a either a fatty acid, a triacylglycerol, a mono- or diacylglycerol, phospholipid,…

Utilizing thin-film solid-phase extraction to assess the effect of organic carbon amendments on the bioavailability of DDT and dieldrin to earthworms

USDA-ARS?s Scientific Manuscript database

Improved approaches are needed to rapidly and accurately assess the bioavailability of persistent, hydrophobic organic compounds in soils at contaminated sites. The performance of a thin-film solid-phase extraction (TF-SPE) assay using vials coated with ethylene vinyl acetate polymer was compared to...

High speed real-time wavefront processing system for a solid-state laser system

NASA Astrophysics Data System (ADS)

Liu, Yuan; Yang, Ping; Chen, Shanqiu; Ma, Lifang; Xu, Bing

2008-03-01

A high speed real-time wavefront processing system for a solid-state laser beam cleanup system has been built. This system consists of a core2 Industrial PC (IPC) using Linux and real-time Linux (RT-Linux) operation system (OS), a PCI image grabber, a D/A card. More often than not, the phase aberrations of the output beam from solid-state lasers vary fast with intracavity thermal effects and environmental influence. To compensate the phase aberrations of solid-state lasers successfully, a high speed real-time wavefront processing system is presented. Compared to former systems, this system can improve the speed efficiently. In the new system, the acquisition of image data, the output of control voltage data and the implementation of reconstructor control algorithm are treated as real-time tasks in kernel-space, the display of wavefront information and man-machine conversation are treated as non real-time tasks in user-space. The parallel processing of real-time tasks in Symmetric Multi Processors (SMP) mode is the main strategy of improving the speed. In this paper, the performance and efficiency of this wavefront processing system are analyzed. The opened-loop experimental results show that the sampling frequency of this system is up to 3300Hz, and this system can well deal with phase aberrations from solid-state lasers.

Physically incorporated extraction phase of solid-phase microextraction by sol-gel technology.

PubMed

Liu, Wenmin; Hu, Yuan; Zhao, Jinghong; Xu, Yuan; Guan, Yafeng

2006-01-13

A sol-gel method for the preparation of solid-phase microextraction (SPME) fiber was described and evaluated. The extraction phase of poly(dimethysiloxane) (PDMS) containing 3% vinyl group was physically incorporated into the sol-gel network without chemical bonding. The extraction phase itself is then partly crosslinked at 320 degrees C, forming an independent polymer network and can withstand desorption temperature of 290 degrees C. The headspace extraction of BTX by the fiber SPME was evaluated and the detection limit of o-xylene was down to 0.26 ng/l. Extraction and determination of organophosphorus pesticides (OPPs) in water, orange juice and red wine by the SPME-GC thermionic specified detector (TSD) was validated. Limits of detection of the method for OPPs were below 10 ng/l except methidathion. Relative standard deviations (RSDs) were in the range of 1-20% for pesticides being tested.

Quantitative high-performance liquid chromatographic determination of retinoids in human serum using on-line solid-phase extraction and column switching. Determination of 9-cis-retinoic acid, 13-cis-retinoic acid, all-trans-retinoic acid, 4-oxo-all-trans-retinoicacid and 4-oxo-13-cis-retinoic acid.

PubMed

Gundersen, T E; Lundanes, E; Blomhoff, R

1997-03-28

A fully automated isocratic high-performance liquid chromatographic method for the determination of 9-cis-retinoic acid, 13-cis-retinoic acid, all-trans-retinoic acid, 4-oxo-13-cis-retinoic acid and 4-oxo-all-trans-retinoic acid, has been developed using on-line solid-phase extraction and a column switching technique allowing clean-up and pre-concentration in a single step. A 500-microliter sample of serum was diluted with 750 microliters of a solution containing 20% acetonitrile and the internal standard 9,10-dimethylanthracene. About 1000 microliters of this mixture was injected on a 20 x 4.6 mm I.D. poly ether ether ketone (PEEK) pre-column with titanium frits packed with Bondapak C18, 37-53 microns, 300 A particles. Proteins and very polar compounds were washed out to waste, from the pre-column, with 0.05% trifluoroacetic acid (TFA)-acetonitrile (8.5:1.5, v/v). More than 200 aliquots of diluted serum could be injected on this pre-column before elevated back-pressure enforces replacement. Components retained on the pre-column were backflushed to the analytical column for separation and detection at 360 nm. Baseline separation was achieved using a single 250 x 4.6 mm I.D. Suplex pKb-100 column and a mobile phase containing 69:10:2:16:3 (v/v) of acetonitrile-methanol-n-butanol-2% ammonium acetate-glacial acetic acid. A total time of analysis of less than 30 min, including sample preparation, was achieved. Recoveries were in the range of 79-86%. The limit of detection was 1-7 ng/ml serum and the precision, in the concentration range 20-1000 ng/ml, was between 1.3 and 4.5% for all five compounds. The method was applied for the analysis of human serum after oral administration of 60 mg Roaccutan. The method is well suited for pharmacological studies, while the endogenous levels of some retinoic acid isomers are below the limit of quantitation.

DNA extraction on bio-chip: history and preeminence over conventional and solid-phase extraction methods.

PubMed

Ayoib, Adilah; Hashim, Uda; Gopinath, Subash C B; Md Arshad, M K

2017-11-01

This review covers a developmental progression on early to modern taxonomy at cellular level following the advent of electron microscopy and the advancement in deoxyribonucleic acid (DNA) extraction for expatiation of biological classification at DNA level. Here, we discuss the fundamental values of conventional chemical methods of DNA extraction using liquid/liquid extraction (LLE) followed by development of solid-phase extraction (SPE) methods, as well as recent advances in microfluidics device-based system for DNA extraction on-chip. We also discuss the importance of DNA extraction as well as the advantages over conventional chemical methods, and how Lab-on-a-Chip (LOC) system plays a crucial role for the future achievements.

Application of solid phase extraction procedures for rare earth elements determination in environmental samples.

PubMed

Pyrzynska, Krystyna; Kubiak, Anna; Wysocka, Irena

2016-07-01

Determination of rare earth elements in environmental samples requires often pre-concentration and separation step due to a low metal content and high concentration of the interfering matrix components. A solid phase extraction technique with different kind of solid sorbents offers a high enrichment factor, rapid phase separation and the possibility of its combination with various detection techniques used either in on-line or off-line mode. The recent developments in this area published over the last five years are presented and discussed in this paper. Copyright © 2016 Elsevier B.V. All rights reserved.

CLOSED-LOOP STRIPPING ANALYSIS (CLSA) OF ...

EPA Pesticide Factsheets

Synthetic musk compounds are used as inexpensive fragrance materials for the production of perfumes and as additives to soap, detergent, and shampoo. They have been found in surface water, fish tissues, and human breast milk. The ubiquity of this class of compounds in the environment is attributable to high use and release into the environment. Current techniques for separating these compounds from fish tissues require tedious sample clean-up procedures. To obtain fat-free extracts, gel permeation chromatography (GPC), column chromatography using alumina, and silica gel, and thin layer chromatography (TLC clean-up procedures are frequently employed. Despite the considerable effort and resources devoted to these processes, a fraction of the lipids and lipid-like compounds frequently remains in the extracts. These low-level lipids foul injection liners, contaminate columns, and yield elevated baselines during gas chromatographic analysis of synthetic musk compounds. In this study, a simple method for the determination of synthetic musk compounds in fish tissues has been developed. Closed-loop stripping of saponified fish tissues in a I -L Wheaton purge- and-trap vessel, is used to strip compounds with high vapor pressures such as synthetic musks from the matrix onto a solid sorbent (Abselut Nexus). This technique is useful for screening biological tissues that contain lipids for musk compounds. Analytes are desorbed from the sorbent trap sequentially with polar an

[Simultaneous determination of 15 industrial synthetic dyes in condiment by solid phase extraction-high performance liquid chromatography].

PubMed

Liu, Min; Li, Xiaolin; Bie, Wei; Wang, Minglin; Feng, Qian

2011-02-01

A new method was established for the determination of 15 industrial synthetic dyes in condiment by solid phase extraction-high performance liquid chromatography (SPE-HPLC). The samples were extracted by methanol-water (1:1, v/v) and purified by a solid phase extraction column. Then, the chromatographic separation was achieved on a Luna C18 column by linear gradient elution. The mobile phase was 10 mmol/L ammonium acetate-acetonitrile (containing 1% acetic acid). The results showed that the 15 industrial synthetic dyes can be separated efficiently. The recoveries of the 15 industrial synthetic dyes spiked in condiment were between 84.6% and 114.2% with the relative standard deviations of 0.9% - 10.3%. The limits of detection of this method was 0.05 - 0.18 mg/kg for the 15 industrial synthetic dyes. The method is simple, sensitive, accurate, repeatable and can be used for simultaneous determination of the 15 illegally added industrial synthetic dyes.

Quantitation of acrylamide in food products by liquid chromatography/mass spectrometry.

PubMed

Eberhart, B Loye; Ewald, Deborah K; Sanders, Robert A; Tallmadge, Daniel H; Zyzak, David V; Strothers, Melissa A

2005-01-01

A simple and inexpensive liquid chromatography/mass spectrometry (LC/MS) method was developed for the quantitation of acrylamide in various food products. The method involved spiking the isotope-substituted internal standard (1-C13 acrylamide) onto 6.00 g of the food product, adding 40 mL distilled/deionized water, and heating at 65 degrees C for 30 min. Afterwards, 10 mL ethylene dichloride was added and the mixture was homogenized for 30 s and centrifuged at 2700 x g for 30 min, and then 8 g supernatant was extracted with 10, 5, and 5 mL portions of ethyl acetate. The extracts were combined, dried with sodium sulfate, and concentrated to 100-200 microL. Acrylamide was determined by analysis of the final extract on a single quadrupole, bench-top mass spectrometer with electrospray ionization, using a 2 mm id C18 column and monitoring m/z = 72 (acrylamide) and m/z = 73 (internal standard). For difficult food matrixes, such as coffee and cocoa, a solid-phase extraction cleanup step was incorporated to improve both chromatography and column lifetime. The method had a limit of quantitation of 10 ppb, and coefficients of determination (r2) for calibration curves were typically better than 0.998. Acceptable spike recovery results were achieved in 11 different food matrixes. Precision in potato chip analyses was 5-8% (relative standard deviation). This method provides an LC/MS alternative to the current LC/MS/MS methods and derivatization gas chromatography/mass spectrometry methods, and is applicable to difficult food products such as coffee, cocoa, and high-salt foods.

Simplified sample preparation method for triclosan and methyltriclosan determination in biota and foodstuff samples.

PubMed

Canosa, P; Rodríguez, I; Rubí, E; Ramil, M; Cela, R

2008-04-25

An improved method for the determination of triclosan (TCS) and methyltriclosan (MTCS) in fish and foodstuff samples is presented. Analytes were simultaneously extracted and purified using the matrix solid-phase dispersion (MSPD) technique, and then selectively determined by gas chromatography with tandem mass spectrometry (GC-MS/MS). Several combinations of dispersants, clean-up co-sorbents and extraction solvents were tested in order to obtain lipid-free extracts and quantitative recoveries for TCS and MTCS. Under optimised conditions, 0.5 g samples were dispersed using 1.5 g of neutral silica in a mortar with a pestle, and transferred to a polypropylene cartridge containing 3 g of silica impregnated with 10% of sulphuric acid (SiO2-H2SO4, 10%, w/w). Analytes were recovered with 10 mL of dichloromethane whereas lipids were oxidized in the layer of acidic silica. The extract was concentrated to dryness and re-constituted with 1 mL of ethyl acetate. Then, a fraction of 0.5 mL was mixed with 50 microL of N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA) and injected in the GC-MS/MS system. The developed method provided absolute recoveries between 77 and 120% for different samples spiked at the low ng g(-1) level, quantification limits in the range of 1-2 ng g(-1) and a considerable simplicity in comparison with previously developed sample preparation approaches. Experiments carried out placing sliced food samples in direct contact with TCS-treated kitchenware surfaces showed the capability of the biocide to migrate into foodstuffs.

Optimization for quick, easy, cheap, effective, rugged and safe extraction of mycotoxins and veterinary drugs by response surface methodology for application to egg and milk.

PubMed

Zhou, Jian; Xu, Jiao-Jiao; Cong, Jin-Mi; Cai, Zeng-Xuan; Zhang, Jing-Shun; Wang, Jun-Lin; Ren, Yi-Ping

2018-01-12

A multiclass method was proposed for the simultaneous determination of various classes of veterinary drugs (n = 65), mycotoxins and metabolites (n = 39) in egg and milk by ultra-high performance liquid chromatography-tandem mass spectrometry. The contaminants were extracted by QuEChERS-based strategy including salt-out partitioning and dispersive solid-phase extraction for cleanup further. With the aim of maximizing throughput and extraction efficiency, Plackett-Burman design was employed initially for screening significant variables. And response surface methodology based on central composite design was conducted to achieve optimal conditions in details: 3.35% (v/v) of formic acid in acetonitrile, 1.2 g of NaCl, 0.5 g of anhydrous NaAc, 300 mg of C18 and 140 mg of primary secondary amine. Satisfactory analytical characteristics in validation, in aspects of accuracy (70%-105% for mycotoxins and quinolones, 55%-80% for sulphonamides and 40%-105% for other veterinary drugs), precision (inter-day RSDs < 14%) and sensitivity (LOQs ranged from 0.01 μg/kg to 31 μg/kg), were achieved under the optimized conditions. The matrix effects were evaluated and compensated by the use of matrix-matched calibration curves (R 2  > 0.987). In practice, 45 eggs and 30 milk samples were investigated by the established method, of which positive finding aflatoxin in milk and sterigmatocystin in eggs. Copyright © 2017 Elsevier B.V. All rights reserved.

Analysis of the herbicide diuron, three diuron degradates, and six neonicotinoid insecticides in water-Method details and application to two Georgia streams

USGS Publications Warehouse

Hladik, Michelle; Calhoun, Daniel L.

2012-01-01

A method for the determination of the widely used herbicide diuron, three degradates of diuron, and six neonicotinoid insecticides in environmental water samples is described. Filtered water samples were extracted by using solid-phase extraction (SPE) with no additional cleanup steps. Quantification of the pesticides from the extracted water samples was done by using liquid chromatography with tandem mass spectrometry (LC/MS/MS). Recoveries in test water samples fortified at 20 nanograms per liter (ng/L) for each compound ranged from 75 to 97 percent; relative standard deviations ranged from 5 to 10 percent. Method detection limits (MDLs) in water ranged from 3.0 to 6.2 ng/L using LC/MS/MS. The method was applied to water samples from two streams in Georgia, Sope Creek and the Chattahoochee River. Diuron and 3,4-dichloroaniline (3,4-DCA) were detected in 100 and 80 percent, respectively, of the samples from the Chattahoochee River, whereas Sope creek had detection frequencies of 15 percent for diuron and 31 percent for 3,4-DCA. Detection frequencies for the neonicotinoid insecticide, imidacloprid, were 60 percent for the Chattahoochee River and 85 percent for Sope Creek. Field matrix-spike recoveries for each compound, when averaged over four water samples, ranged from 79 to 100 percent. The average percentage difference between replicate pairs for all compounds detected in the field samples was 10.1 (± 4.5) percent.

Sulfonated poly(styrene-divinylbenzene) modified with amines and the application for pipette-tip solid-phase extraction of carbendazim in apples.

PubMed

Ma, Yuxin; Liu, Lingling; Tang, Weiyang; Zhu, Tao

2017-10-01

Sulfonated poly(styrene-divinylbenzene) modified with five kinds of amine functional groups was applied to the determination of carbendazim in apple samples with a pipette-tip solid-phase extraction method. The structures of the polymers were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Five different modifications of the solid-phase extraction sorbent based on sulfonated poly(styrene-divinylbenzene) were tested under static and pipette-tip solid-phase extraction conditions. The polymer modified with p-methoxyaniline showed the best recognition capacity and adsorption amount for carbendazim. Under the optimum conditions, 3.00 mg of the adsorbent, 1.00 mL of ethyl acetate as washing solvent, and 1.00 mL of ammonia/acetonitrile (5:95, v/v) as elution solvent were used in the pretreatment procedure of apple samples. The calibration graphs of carbendazim in methanol were linear over 5.00-200.00 μg/mL, and the limits of detection and quantification were 0.01 and 0.03 μg/mL, respectively. The method recoveries of carbendazim were in the range of 91.31-98.13% with associated intraday relative standard deviations of 0.76-2.13% and interday relative standard deviations of 1.10-1.85%. Sulfonated poly(styrene-divinylbenzene) modified with p-methoxyaniline showed satisfactory results (recovery: 97.96%) and potential for the rapid purification of carbendazim in apple samples combined with the pipette-tip solid-phase extraction. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Metal-organic framework based in-syringe solid-phase extraction for the on-site sampling of polycyclic aromatic hydrocarbons from environmental water samples.

PubMed

Zhang, Xiaoqiong; Wang, Peiyi; Han, Qiang; Li, Hengzhen; Wang, Tong; Ding, Mingyu

2018-04-01

In-syringe solid-phase extraction is a promising sample pretreatment method for the on-site sampling of water samples because of its outstanding advantages of portability, simple operation, short extraction time, and low cost. In this work, a novel in-syringe solid-phase extraction device using metal-organic frameworks as the adsorbent was fabricated for the on-site sampling of polycyclic aromatic hydrocarbons from environmental waters. Trace polycyclic aromatic hydrocarbons were effectively extracted through the self-made device followed by gas chromatography with mass spectrometry analysis. Owing to the excellent adsorption performance of metal-organic frameworks, the analytes could be completely adsorbed during one adsorption cycle, thus effectively shortening the extraction time. Moreover, the adsorbed analytes could remain stable on the device for at least 7 days, revealing the potential of the self-made device for on-site sampling of degradable compounds in remote regions. The limit of detection ranged from 0.20 to 1.9 ng/L under the optimum conditions. Satisfactory recoveries varying from 84.4 to 104.5% and relative standard deviations below 9.7% were obtained in real samples analysis. The results of this study promote the application of metal-organic frameworks in sample preparation and demonstrate the great potential of in-syringe solid-phase extraction for the on-site sampling of trace contaminants in environmental waters. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of inorganic arsenic in algae using bromine halogenation and on-line nonpolar solid phase extraction followed by hydride generation atomic flourescence spectrometry

USDA-ARS?s Scientific Manuscript database

Accurate, stable and fast analysis of toxic inorganic arsenic (iAs) in complicated and arsenosugar-rich algae matrix is always a challenge. Herein, a novel analytical method for iAs in algae was reported, using bromine halogenation and on-line nonpolar solid phase extraction (SPE) followed by hydrid...

METHOD 544. DETERMINATION OF MICROCYSTINS AND NODULARIN IN DRINKING WATER BY SOLID PHASE EXTRACTION AND LIQUID CHROMATOGRAPHY/TANDEM MASS SPECTROMETRY (LC/MS/MS)

EPA Science Inventory

Method 544 is an accurate and precise analytical method to determine six microcystins (including MC-LR) and nodularin in drinking water using solid phase extraction and liquid chromatography tandem mass spectrometry (SPE-LC/MS/MS). The advantage of this SPE-LC/MS/MS is its sensi...

Application of pseudo-template molecularly imprinted polymers by atom transfer radical polymerization to the solid-phase extraction of pyrethroids.

PubMed

Zhang, Ming; He, Juan; Shen, Yanzheng; He, Weiye; Li, Yuanyuan; Zhao, Dongxin; Zhang, Shusheng

2018-02-01

A polymer-based adsorption medium with molecular recognition ability for homologs of pyrethroids was prepared by atom transfer radical polymer iration using a fragment imprinting technique. Phenyl ether-biphenyl eutectic was utilized as a pseudo-template molecule, and the adsorption medium prepared was evaluated by solid-phase extraction and gas chromatography. Selectivity of the medium for pyrethroids was evaluated using it as solid phase extraction packing by Gas Chromatography. The results demonstrated that the absorption amount of bifenthrin, fenpropathrin, permethrin, cypermethrin, fenvalerate, Dursban and pentachloronitrobenzene for molecularly imprinted polymers were 2.32, 2.12, 2.18, 2.20, 2.30, 1.30 and 1.40mgg -1 , respectively, while the non-imprinted polymers were 1.20, 1.13, 1.25, 1.05, 1.20, 1.23 and 1.32mgg -1 , respectively. The rebinding test based on the molecularly imprinted solid phase extraction column technique showed the recoveries of honey sample spiked with seven insecticides within 88.5-106.2%, with relative standard deviations of 2.38-5.63%. Finally, the method was successfully applied to the analysis of pyrethroids in a honey sample. Copyright © 2017 Elsevier B.V. All rights reserved.

Analysis of lignans in Magnoliae Flos by turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry.

PubMed

Zhou, Xuan; Chen, Cen; Ye, Xiaolan; Song, Fenyun; Fan, Guorong; Wu, Fuhai

2016-04-01

In this study, a method coupling turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry was developed for analyzing the lignans in Magnoliae Flos. By the online pretreatment of turbulent flow chromatography solid-phase extraction, the impurities removal and analytes concentration were automatically processed, and the lignans were separated rapidly and well. Seven lignans of Magnoliae Flos including epieudesmin, magnolin, 1-irioresinol-B-dimethyl ether, epi-magnolin, fargesin aschantin, and demethoxyaschantin were identified by comparing their retention behavior, UV spectra, and mass spectra with those of reference substances or literature data. The developed method was validated, and the good results showed that the method was not only automatic and rapid, but also accurate and reliable. The turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry method holds a high potential to become an effective method for the quality control of lignans in Magnoliae Flos and a useful tool for the analysis of other complex mixtures. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Advanced analytical techniques for the extraction and characterization of plant-derived essential oils by gas chromatography with mass spectrometry.

PubMed

Waseem, Rabia; Low, Kah Hin

2015-02-01

In recent years, essential oils have received a growing interest because of the positive health effects of their novel characteristics such as antibacterial, antifungal, and antioxidant activities. For the extraction of plant-derived essential oils, there is the need of advanced analytical techniques and innovative methodologies. An exhaustive study of hydrodistillation, supercritical fluid extraction, ultrasound- and microwave-assisted extraction, solid-phase microextraction, pressurized liquid extraction, pressurized hot water extraction, liquid-liquid extraction, liquid-phase microextraction, matrix solid-phase dispersion, and gas chromatography (one- and two-dimensional) hyphenated with mass spectrometry for the extraction through various plant species and analysis of essential oils has been provided in this review. Essential oils are composed of mainly terpenes and terpenoids with low-molecular-weight aromatic and aliphatic constituents that are particularly important for public health. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of Total Biotin by Liquid Chromatography Coupled with Immunoaffinity Column Cleanup Extraction: Multilaboratory Testing, Final Action 2016.02.

PubMed

Joseph, George; Devi, Ranjani; Marley, Elaine C; Leeman, David

2018-05-01

Single- and multilaboratory testing data have provided systematic scientific evidence that a simple, selective, accurate, and precise method can be used as a potential candidate reference method for dispute resolution in determining total biotin in all forms of infant, adult, and/or pediatric formula. Using LC coupled with immunoaffinity column cleanup extraction, the method fully meets the intended purpose and applicability statement in AOAC Standard Method Performance Requirement 2014.005. The method was applied to a cross-section of infant formula and adult nutritional matrixes, and acceptable precision and accuracy were established. The analytical platform is inexpensive, and the method can be used in almost any laboratory worldwide with basic facilities. The immunoaffinity column cleanup extraction is the key step to successful analysis.

Comprehensive determination of macrolide antibiotics, their synthesis intermediates and transformation products in wastewater effluents and ambient waters by liquid chromatography-tandem mass spectrometry.

PubMed

Senta, Ivan; Krizman-Matasic, Ivona; Terzic, Senka; Ahel, Marijan

2017-08-04

Macrolide antibiotics are a prominent group of emerging contaminants frequently found in wastewater effluents and wastewater-impacted aquatic environments. In this work, a novel analytical method for simultaneous determination of parent macrolide antibiotics (azithromycin, erythromycin, clarithromycin and roxithromycin), along with their synthesis intermediates, byproducts, metabolites and transformation products in wastewater and surface water was developed and validated. Samples were enriched using solid-phase extraction on Oasis HLB cartridges and analyzed by reversed-phase liquid chromatography coupled to electrospray ionization tandem mass spectrometry. The target macrolide compounds were separated on an ACE C18 PFP column and detected using multiple reaction monitoring in positive ionization polarity. The optimized method, which included an additional extract clean-up on strong anion-exchange cartridges (SAX), resulted in high recoveries and accuracies, low matrix effects and improved chromatographic separation of the target compounds, even in highly complex matrices, such as raw wastewater. The developed method was applied to the analysis of macrolide compounds in wastewater and river water samples from Croatia. In addition to parent antibiotics, several previously unreported macrolide transformation products and/or synthesis intermediates were detected in municipal wastewater, some of them reaching μg/L levels. Moreover, extremely high concentrations of macrolides up to mg/L level were found in pharmaceutical industry effluents, indicating possible importance of this source to the total loads into ambient waters. The results revealed a significant contribution of synthesis intermediates and transformation products to the overall mass balance of macrolides in the aquatic environment. Copyright © 2017. Published by Elsevier B.V.

UPLC-MS/MS determination of ptaquiloside and pterosin B in preserved natural water.

PubMed

Clauson-Kaas, Frederik; Hansen, Hans Christian Bruun; Strobel, Bjarne W

2016-11-01

The naturally occurring carcinogen ptaquiloside and its degradation product pterosin B are found in water leaching from bracken stands. The objective of this work is to present a new sample preservation method and a fast UPLC-MS/MS method for quantification of ptaquiloside and pterosin B in environmental water samples, employing a novel internal standard. A faster, reliable, and efficient method was developed for isolation of high purity ptaquiloside and pterosin B from plant material for use as analytical standards, with purity verified by 1 H-NMR. The chemical analysis was performed by cleanup and preconcentration of samples with solid phase extraction, before analyte quantification with UPLC-MS/MS. By including gradient elution and optimizing the liquid chromatography mobile phase buffer system, a total run cycle of 5 min was achieved, with method detection limits, including preconcentration, of 8 and 4 ng/L for ptaquiloside and pterosin B, respectively. The use of loganin as internal standard improved repeatability of the determination of both analytes, though it could not be employed for sample preparation. Buffering raw water samples in situ with ammonium acetate to pH ∼5.5 decisively increased sample integrity at realistic transportation and storing conditions prior to extraction. Groundwater samples collected in November 2015 at the shallow water table below a Danish bracken stand were preserved and analyzed using the above methods, and PTA concentrations of 3.8 ± 0.24 μg/L (±sd, n = 3) were found, much higher than previously reported. Graphical abstract Workflow overview of ptaquiloside determination.

Development and validation of a method for determination of corticosteroids in pig fat using liquid chromatography-tandem mass spectrometry.

PubMed

Tölgyesi, Adám; Sharma, Virender K; Fekete, Jeno

2011-02-15

A new method was developed to determine five corticosteroids (prednisolone, methylprednisone, flumethasone, dexamethasone, and methylprednisolone) in pig fat samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS) utilizing an optimized liquid-liquid extraction (LLE) and subsequent solid-phase extraction (SPE) for sample clean-up. In the sample preparation, a pig fat sample was dissolved in n-hexane and then extracted into the methanol-water (50/50, v/v) mixture that enabled extraction of only medium polar corticosteroids and not the non-polar components of matrices. This extract was cleaned-up and concentrated on polymeric Oasis HLB SPE cartridge. Separation involved isocratic solvent (methanol-acetate buffer, pH 5.4) and Ascentis Express Fused-Core type HLPC column; reduced the analysis time to 7.5 min, which is at least two times lower than time required for separation using conventional techniques. Other advantage of the developed method is the minimized ion suppression of LC-MS/MS analysis, which allowed detection of corticosteroids in sub μg/kg. Method was validated according to European Union (EU) Commission Decision 2002/657/EC. Measured parameters such as selectivity, linearity, recovery, within-laboratory reproducibility, decision limit, and detection capability satisfied the EU Directive. Ranges of mean recoveries and within-laboratory reproducibility were 81-100% and 8.0-20.5%, respectively. Decision limits were calculated in the range from 4.5 to 11.9 μg/kg for MRL compounds and varied from 0.1 to 0.2 μg/kg for banned substances. Limit of detections (LODs), calculated as three time signal-to-noise ratio, were in the range of 0.1-0.3 μg/kg. Copyright © 2010 Elsevier B.V. All rights reserved.

Rapid and sensitive determination of major polyphenolic components in Euphoria longana Lam. seeds using matrix solid-phase dispersion extraction and UHPLC with hybrid linear ion trap triple quadrupole mass spectrometry.

PubMed

Rathore, Atul S; Sathiyanarayanan, L; Deshpande, Shreekant; Mahadik, Kakasaheb R

2016-11-01

A rapid and sensitive method for the extraction and determination of four major polyphenolic components in Euphoria longana Lam. seeds is presented for the first time based on matrix solid-phase dispersion extraction followed by ultra high performance liquid chromatography with hybrid triple quadrupole linear ion trap mass spectrometry. Matrix solid-phase dispersion method was designed for the extraction of Euphoria longana seed constituents and compared with microwave-assisted extraction and ultrasonic-assisted extraction methods. An Ultra high performance liquid chromatography with hybrid triple quadrupole linear ion-trap mass spectrometry method was developed for quantitative analysis in multiple-reaction monitoring mode in negative electrospray ionization. The chromatographic separation was accomplished using an ACQUITY UPLC BEH C 18 (2.1 mm × 50 mm, 1.7 μm) column with gradient elution of 0.1% aqueous formic acid and 0.1% formic acid in acetonitrile. The developed method was validated with acceptable linearity (r 2 > 0.999), precision (RSD ≤ 2.22%) and recovery (RSD ≤ 2.35%). The results indicated that matrix solid-phase dispersion produced comparable extraction efficiency compared with other methods nevertheless was more convenient and time-saving with reduced requirements on sample and solvent volumes. The proposed method is rapid and sensitive in providing a promising alternative for extraction and comprehensive determination of active components for quality control of Euphoria longana products. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous determination of azathioprine and 6-mercaptopurine by high-performance liquid chromatography.

PubMed

Van Os, E C; McKinney, J A; Zins, B J; Mays, D C; Schriver, Z H; Sandborn, W J; Lipsky, J J

1996-04-26

A specific, sensitive, single-step solid-phase extraction and reversed-phase high-performance liquid chromatographic method for the simultaneous determination of plasma 6-mercaptopurine and azathioprine concentrations is reported. Following solid-phase extraction, analytes are separated on a C18 column with mobile phase consisting of 0.8% acetonitrile in 1 mM triethylamine, pH 3.2, run on a gradient system. Quantitation limits were 5 ng/ml and 2 ng/ml for azathioprine and 6-mercaptopurine, respectively. Peak heights correlated linearly to known extracted standards for 6-mercaptopurine and azathioprine (r = 0.999) over a range of 2-200 ng/ml. No chromatographic interferences were detected.

Measurement of thyroxine and its glucuronide in municipal wastewater and solids using weak anion exchange solid phase extraction and ultrahigh performance liquid chromatography-tandem mass spectrometry.

PubMed

Brown, Alistair K; Wong, Charles S

2017-11-24

A solids extraction method, using sonication in combination with weak anion exchange solid phase extraction, was created to extract thyroxine (T4) and thyroxine-O-β-d-glucuronide (T4-Glc) simultaneously from wastewaters and sludges, and to quantify these compounds via reversed-phase ultra-high performance liquid chromatography-tandem mass spectrometry. The method limits of quantification were all in the low ng/g (dry weight solids) range for both T4 and T4-Glc: 2.13 and 2.63ng/g respectively in primary wastewater, 4.3 and 28.3ng/g for primary suspended solids, for 1.1 and 3.7ng/g for return activated sludge. Precision for measurements of T4 and T4-Glc were 2.6 and 6.5% (intraday) and 9.6 and 5.7% (interday) respectively, while linearity was 0.9967 and 0.9943 respectively. Overall recoveries for T4 and T4-Glc in primary suspended solids were 94% and 95%, and 86 and 101% in primary wastewater, respectively. Extraction efficiency tests using primary sludge determined that one methanol aliquot was sufficient during the extraction process as opposed to 2 or 3 aliquots. Mass loadings at the North Main Wastewater Treatment Plant in Winnipeg, Canada showed 316%, 714%, and 714% greater T4-Glc than T4 associated with the suspended solids of the primary, secondary, and final effluent respectively, yet 765% more T4 than T4-Glc associated with the solids of the mixed liquor. Moreover, 26% of T4 and 49% of T4-Glc were associated with the suspended solids during the treatment process. This method demonstrates the need to assess accurately both metabolite conjugates of contaminants of emerging concern, as well as the sorbed levels of particle-reactive analytes such as T4 in the aquatic environment. Copyright © 2017 Elsevier B.V. All rights reserved.

High-throughput method based on quick, easy, cheap, effective, rugged and safe followed by liquid chromatography-multi-wavelength detection for the quantification of multiclass polyphenols in wines.

PubMed

Fontana, Ariel R; Bottini, Rubén

2014-05-16

In this work, a reliable, simple, fast, inexpensive and robust sample preparation approach for the determination of multiclass polyphenols in wine samples is proposed. The polyphenols selected for this work were gallic acid, (+)-catechin, (-)-epicatechin, caffeic acid, syringic acid, coumaric acid, ferulic acid, trans-resveratrol, quercetin and cinnamic acid. The method is based on QuEChERS (quick, easy, cheap, effective, rugged and safe) extraction technique coupled with dispersive solid-phase extraction (d-SPE) clean-up. Under optimized conditions, the analytes were extracted from 5mL wine samples (previously acidified with 1% formic acid) using 2.5mL acetonitrile. For phase separation, 1.5g NaCl and 4g anhydrous MgSO4 were added. Then, a 1mL aliquot of the partitioned supernatant was cleaned-up using d-SPE with a combination of 150mg CaCl2, 50mg primary-secondary amine (PSA) and 50mgC18 as sorbents. A 250μL aliquot of the obtained cleaned extract was concentrated to dryness and taken up with the initial mobile phase previous to liquid chromatography-multi-wavelength detection (LC-MWD). The proposed method provided limits of detection (LODs) ranging from 0.004 to 0.079μgmL(-1) and an inter-day variability below 12% RSD for all analytes in red and white wine samples. Considering external calibration (red wines) and matrix-matched calibration (white wines) as quantification techniques, the overall recoveries (accuracy) of the method ranged between 75.0% and 119.6% for red and white wine samples, respectively. The developed method was applied for the determination of polyphenols in 10 wines produced in Argentina. Nine phenolic compounds were determined, at concentrations above detectable levels in the method. The maximum concentrations corresponded to (-)-epicatechin in white wines, while gallic acid and (+)-catechin were the most abundant in red wines. Copyright © 2014 Elsevier B.V. All rights reserved.

ACCELERATED SOLVENT EXTRACTION COMBINED WITH ...

EPA Pesticide Factsheets

A research project was initiated to address a recurring problem of elevated detection limits above required risk-based concentrations for the determination of semivolatile organic compounds in high moisture content solid samples. This project was initiated, in cooperation with the EPA Region 1 Laboratory, under the Regional Methods Program administered through the ORD Office of Science Policy. The aim of the project was to develop an approach for the rapid removal of water in high moisture content solids (e.g., wetland sediments) in preparation for analysis via Method 8270. Alternative methods for water removal have been investigated to enhance compound solid concentrations and improve extraction efficiency, with the use of pressure filtration providing a high-throughput alternative for removal of the majority of free water in sediments and sludges. In order to eliminate problems with phase separation during extraction of solids using Accelerated Solvent Extraction, a variation of a water-isopropanol extraction method developed at the USGS National Water Quality Laboratory in Denver, CO is being employed. The concentrations of target compounds in water-isopropanol extraction fluids are subsequently analyzed using an automated Solid Phase Extraction (SPE)-GC/MS method developed in our laboratory. The coupled approaches for dewatering, extraction, and target compound identification-quantitation provide a useful alternative to enhance sample throughput for Me

Fast determination of four polar contaminants in soy nutraceutical products by liquid chromatography coupled to tandem mass spectrometry.

PubMed

Domingos Alves, Renata; Romero-González, Roberto; López-Ruiz, Rosalía; Jiménez-Medina, M L; Garrido Frenich, Antonia

2016-11-01

An analytical method based on a modified QuPPe (quick polar pesticide) extraction procedure coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was evaluated for the determination of four polar compounds (chlorate, fosetyl-Al, maleic hydrazide, and perchlorate) in nutraceutical products obtained from soy. Experimental conditions including extraction such as solvent, acidification, time, and clean-up sorbents were varied. Acidified acetonitrile (1 % formic acid, v/v) was used as extraction solvent instead of methanol (conventional QuPPe), which provides a doughy mixture which cannot be injected into the LC. Clean-up or derivatization steps were avoided. For analysis, several stationary phases were evaluated and Hypercarb (porous graphitic carbon) provided the best results. The optimized method was validated and recoveries ranged between 46 and 119 %, and correction factors can be used for quantification purposes bearing in mind that inter-day precision was equal to or lower than 17 %. Limits of quantification (LOQs) ranged from 4 to 100 μg kg -1 . Soy-based nutraceutical products were analyzed and chlorate was detected in five samples at concentrations between 63 and 1642 μg kg -1 . Graphical Abstract Analysis of polar compounds in soy-based nutraceutical products.

Application of solid-phase extraction to agar-supported fermentation.

PubMed

Le Goff, Géraldine; Adelin, Emilie; Cortial, Sylvie; Servy, Claudine; Ouazzani, Jamal

2013-09-01

Agar-supported fermentation (Ag-SF), a variant of solid-state fermentation, has recently been improved by the development of a dedicated 2 m(2) scale pilot facility, Platotex. We investigated the application of solid-phase extraction (SPE) to Ag-SF in order to increase yields and minimize the contamination of the extracts with agar constituents. The selection of the appropriate resin was conducted on liquid-state fermentation and Diaion HP-20 exhibited the highest recovery yield and selectivity for the metabolites of the model fungal strains Phomopsis sp. and Fusarium sp. SPE applied to Ag-SF resulted in a particular compartmentalization of the culture. The mycelium that requires oxygen to grow migrates to the top layer and formed a thick biofilm. The resin beads intercalate between the agar surface and the mycelium layer, and trap directly the compounds secreted by the mycelium through a "solid-solid extraction" (SSE) process. The resin/mycelium layer is easily recovered by scraping the surface and the target metabolites extracted by methanol. Ag-SF associated to SSE represents an ideal compromise for the production of bioactive secondary metabolites with limited economic and environmental impact.

Analytical methodologies based on LC-MS/MS for monitoring selected emerging compounds in liquid and solid phases of the sewage sludge.

PubMed

Boix, C; Ibáñez, M; Fabregat-Safont, D; Morales, E; Pastor, L; Sancho, J V; Sánchez-Ramírez, J E; Hernández, F

2016-01-01

In this work, two analytical methodologies based on liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) were developed for quantification of emerging pollutants identified in sewage sludge after a previous wide-scope screening. The target list included 13 emerging contaminants (EC): thiabendazole, acesulfame, fenofibric acid, valsartan, irbesartan, salicylic acid, diclofenac, carbamazepine, 4-aminoantipyrine (4-AA), 4-acetyl aminoantipyrine (4-AAA), 4-formyl aminoantipyrine (4-FAA), venlafaxine and benzoylecgonine. The aqueous and solid phases of the sewage sludge were analyzed making use of Solid-Phase Extraction (SPE) and UltraSonic Extraction (USE) for sample treatment, respectively. The methods were validated at three concentration levels: 0.2, 2 and 20 μg L(-1) for the aqueous phase, and 50, 500 and 2000 μg kg(-1) for the solid phase of the sludge. In general, the method was satisfactorily validated, showing good recoveries (70-120%) and precision (RSD < 20%). Regarding the limit of quantification (LOQ), it was below 0.1 μg L(-1) in the aqueous phase and below 50 μg kg(-1) in the solid phase for the majority of the analytes. The method applicability was tested by analysis of samples from a wider study on degradation of emerging pollutants in sewage sludge under anaerobic digestion. The key benefits of these methodologies are: • SPE and USE are appropriate sample procedures to extract selected emerging contaminants from the aqueous phase of the sewage sludge and the solid residue. • LC-MS/MS is highly suitable for determining emerging contaminants in both sludge phases. • Up to our knowledge, the main metabolites of dipyrone had not been studied before in sewage sludge.

Bacterial toxicity assessment of drinking water treatment residue (DWTR) and lake sediment amended with DWTR.

PubMed

Yuan, Nannan; Wang, Changhui; Pei, Yuansheng

2016-11-01

Drinking water treatment residue (DWTR) seems to be very promising for controlling lake sediment pollution. Logically, acquisition of the potential toxicity of DWTR will be beneficial for its applications. In this study, the toxicity of DWTR and sediments amended with DWTR to Aliivibrio fischeri was evaluated based on the Microtox(®) solid and leachate phase assays, in combination with flow cytometry analyses and the kinetic luminescent bacteria test. The results showed that both solid particles and aqueous/organic extracts of DWTR exhibited no toxicity to the bacterial luminescence and growth. The solid particles of DWTR even promoted bacterial luminescence, possibly because DWTR particles could act as a microbial carrier and provide nutrients for bacteria growth. Bacterial toxicity (either luminescence or growth) was observed from the solid phase and aqueous/organic extracts of sediments with or without DWTR addition. Further analysis showed that the solid phase toxicity was determined to be related mainly to the fixation of bacteria to fine particles and/or organic matter, and all of the observed inhibition resulting from aqueous/organic extracts was identified as non-significant. Moreover, DWTR addition not only had no adverse effect on the aqueous/organic extract toxicity of the sediment but also reduced the solid phase toxicity of the sediment. Overall, in practical application, the solid particles, the water-soluble substances transferred to surface water or the organic substances in DWTR had no toxicity or any delayed effect on bacteria in lakes, and DWTR can therefore be considered as a non-hazardous material. Copyright © 2016 Elsevier Ltd. All rights reserved.

AUTOMATED ANALYSIS OF AQUEOUS SAMPLES CONTAINING PESTICIDES, ACIDIC/BASIC/NEUTRAL SEMIVOLATILES AND VOLATILE ORGANIC COMPOUNDS BY SOLID PHASE EXTRACTION COUPLED IN-LINE TO LARGE VOLUME INJECTION GC/MS

EPA Science Inventory

Data is presented on the development of a new automated system combining solid phase extraction (SPE) with GC/MS spectrometry for the single-run analysis of water samples containing a broad range of organic compounds. The system uses commercially available automated in-line 10-m...

Solid Phase Micro Extraction (SPME)

NASA Technical Reports Server (NTRS)

1998-01-01

Internation Flavors and Fragrances Inc. proprietary research technology, Solid Phase Micro Extraction (SPME) utilizes a special fiber needle placed directly next to the bloom of the living flower to collect the fragrance molecules. SPME was used in the Space Flower experiment aboard STS-95 space shuttle mission, after which Dr. Braja Mookherjee (left) and Subha Patel of IFF will analyze the effects of gravity on the Overnight Scentsation rose plant.

DEVELOPMENT OF METHOD 535 FOR THE DETERMINATION OF CHLOROACETANILIDE AND OTHER ACETAMIDE HERBICIDE DEGRADATES IN DRINKING WATER BY SOLID PHASE EXTRACTION AND LIQUID CHROMATOGRAPHY/TANDEM MASS SPECTROMETRY

EPA Science Inventory

EPA Method 535 has been developed in order to provide a method for the analysis of "Alachlor ESA and other acetanilide degradation products" which are listed on U.S. EPA's 1998 Drinking Water Contaminant Candidate List. Method 535 uses solid phase extraction with a nonporous gr...

Solid phase extraction membrane

DOEpatents

Carlson, Kurt C [Nashville, TN; Langer, Roger L [Hudson, WI

2002-11-05

A wet-laid, porous solid phase extraction sheet material that contains both active particles and binder and that possesses excellent wet strength is described. The binder is present in a relatively small amount while the particles are present in a relatively large amount. The sheet material is sufficiently strong and flexible so as to be pleatable so that, for example, it can be used in a cartridge device.

Comparison of solvent extraction and solid-phase extraction for the determination of polychlorinated biphenyls in transformer oil.

PubMed

Mahindrakar, A N; Chandra, S; Shinde, L P

2014-01-01

Solid-phase extraction (SPE) of nine polychlorinated biphenyls (PCBs) from transformer oil samples was evaluated using octadecyl (CI8)-bonded porous silica. The efficiency of SPE of these PCBs was compared with those obtained by solvent extraction with DMSO and hexane. Average recoveries exceeding 95% for these PCBs were obtained via the SPE method using small cartridges containing 100mg of 40 pm CI8-bonded porous silica. The average recovery by solvent extraction with DMSO and hexane exceeded 83%. It was concluded that the recoveries and precision for the solvent extraction of PCBs were poorer than those for the SPE. Copyright © 2013 Elsevier Ltd. All rights reserved.

ACCELERATED SOLVENT EXTRACTION COMBINED WITH AUTOMATED SOLID PHASE EXTRACTION-GC/MS FOR ANALYSIS OF SEMIVOLATILE COMPOUNDS IN HIGH MOISTURE CONTENT SOLID SAMPLES

EPA Science Inventory

A research project was initiated to address a recurring problem of elevated detection limits above required risk-based concentrations for the determination of semivolatile organic compounds in high moisture content solid samples. This project was initiated, in cooperation with t...

Extraction and identification of cyclobutanones from irradiated cheese employing a rapid direct solvent extraction method.

PubMed

Tewfik, Ihab

2008-01-01

2-Alkylcyclobutanones (cyclobutanones) are accepted as chemical markers for irradiated foods containing lipid. However, current extraction procedures (Soxhlet-florisil chromatography) for the isolation of these markers involve a long and tedious clean-up regime prior to gas chromatography-mass spectrophotometry identification. This paper outlines an alternative isolation and clean-up method for the extraction of cyclobutanones in irradiated Camembert cheese. The newly developed direct solvent extraction method enables the efficient screening of large numbers of food samples and is not as resource intensive as the BS EN 1785:1997 method. Direct solvent extraction appears to be a simple, robust method and has the added advantage of a considerably shorter extraction time for the analysis of foods containing lipid.

Solid-phase microextraction coupled with high performance liquid chromatography: a complementary technique to solid-phase microextraction-gas chromatography for the analysis of pesticide residues in strawberries.

PubMed

Wang, Z; Hennion, B; Urruty, L; Montury, M

2000-11-01

Solid-phase microextraction coupled with high performance liquid chromatography has been studied for the analysis of methiocarb, napropamide, fenoxycarb and bupirimate in strawberries. The strawberries were blended and centrifuged. Then, an aliquot of the resulting extracting solution was subjected to solid-phase microextraction (SPME) on a 60 microns polydimethylsiloxane/divinylbenzene (PDMS/DVB) fibre for 45 min at room temperature. The extracted pesticides on the SPME fibre were desorbed into SPME/high performance liquid chromatography (HPLC) interface for HPLC analysis with diode-array detection (DAD). The method is organic solvent-free for the whole extraction process and is simple and easy to manipulate. The detection limits were shown to be at low microgram kg-1 level and the linear response covered the range from 0.05 to 2 mg kg-1 of pesticides in strawberries with a regression coefficient larger than 0.99. A good repeatability with RSDs between 2.92 and 9.25% was obtained, depending on compounds.

Cleanup Verification Package for the 118-F-1 Burial Ground

DOE Office of Scientific and Technical Information (OSTI.GOV)

E. J. Farris and H. M. Sulloway

2008-01-10

This cleanup verification package documents completion of remedial action for the 118-F-1 Burial Ground on the Hanford Site. This burial ground is a combination of two locations formerly called Minor Construction Burial Ground No. 2 and Solid Waste Burial Ground No. 2. This waste site received radioactive equipment and other miscellaneous waste from 105-F Reactor operations, including dummy elements and irradiated process tubing; gun barrel tips, steel sleeves, and metal chips removed from the reactor; filter boxes containing reactor graphite chips; and miscellaneous construction solid waste.

Solid-phase extraction with the metal-organic framework MIL-101(Cr) combined with direct analysis in real time mass spectrometry for the fast analysis of triazine herbicides.

PubMed

Li, Xianjiang; Xing, Jiawei; Chang, Cuilan; Wang, Xin; Bai, Yu; Yan, Xiuping; Liu, Huwei

2014-06-01

MIL-101(Cr) is an excellent metal-organic framework with high surface area and nanoscale cavities, making it promising in solid-phase extraction. Herein, we used MIL-101(Cr) as a solid-phase extraction packing material combined with fast detection of direct analysis in real time mass spectrometry (DART-MS) for the analysis of triazine herbicides. After systematic optimization of the operation parameters, including the gas temperature of DART, the moving speed of the 1D platform, solvent for desorption, amount of MIL-101(Cr) extraction time, eluent volume and salt concentration, this method can realize the simultaneous detection of five kinds of triazine herbicides. The limits of detection were 0.1∼0.2 ng/mL and the linear ranges covered more than two orders of magnitude with the quantitation limits of 0.5∼1 ng/mL. Moreover, the developed method has been applied for the analysis of lake water samples and the recoveries for spiked analytes were in the range of 85∼110%. These results showed that solid-phase extraction with metal-organic frameworks is an efficient sample preparation approach for DART-MS analysis and could find more applications in environmental analysis. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effectiveness of Liquid-Liquid Extraction, Solid Phase Extraction, and Headspace Technique for Determination of Some Volatile Water-Soluble Compounds of Rose Aromatic Water

PubMed Central

2017-01-01

Steam distillation is used to isolate scent of rose flowers. Rose aromatic water is commonly used in European cuisine and aromatherapy besides its use in cosmetic industry for its lovely scent. In this study, three different sampling techniques, liquid-liquid extraction (LLE), headspace technique (HS), and solid phase extraction (SPE), were compared for the analysis of volatile water-soluble compounds in commercial rose aromatic water. Some volatile water-soluble compounds of rose aromatic water were also analyzed by gas chromatography mass spectrometry (GCMS). In any case, it was concluded that one of the solid phase extraction methods led to higher recoveries for 2-phenylethyl alcohol (PEA) in the rose aromatic water than the liquid-liquid extraction and headspace technique. Liquid-liquid extraction method provided higher recovery ratios for citronellol, nerol, and geraniol than others. Ideal linear correlation coefficient values were observed by GCMS for quantitative analysis of volatile compounds (r2 ≥ 0.999). Optimized methods showed acceptable repeatability (RSDs < 5%) and excellent recovery (>95%). For compounds such as α-pinene, linalool, β-caryophyllene, α-humulene, methyl eugenol, and eugenol, the best recovery values were obtained with LLE and SPE. PMID:28791049

Development of a multi-residue enantiomeric analysis method for 9 pesticides in soil and water by chiral liquid chromatography/tandem mass spectrometry.

PubMed

Li, Yuanbo; Dong, Fengshou; Liu, Xingang; Xu, Jun; Chen, Xiu; Han, Yongtao; Liang, Xuyang; Zheng, Yongquan

2013-04-15

A novel and sensitive chiral liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous measuring individual enantiomers of 9 pesticides including herbicides, insecticides, and fungicides in soil and water. The separation and determination were performed using reversed-phase chromatography on an amylose chiral stationary phase, a Chiralpak AD-RH column, under gradient elution using a mixture of ACN-2mM ammonium acetate in water as the mobile phase at 0.45 mL/min flow rate. The effects of three cellulose-based columns and three amylose-based columns on the separation were also investigated. The QuEChERS (acronym for Quick, Easy, Cheap, Effective, Rugged and Safe) method and solid-phase extraction (SPE) were used for the extraction and clean-up of the soil and water samples, respectively. Parameters including the matrix effect, linearity, precision, accuracy and stability were undertaken. Under optimal conditions, the mean recoveries for all enantiomers from the soil and water samples were ranged from 77.8% to 106.2% with the relative standard deviations (RSD) less than 14.2%. Good linearity (at least R(2) ≥ 0.9986) was obtained for all studied analytes in the soil and water matrix calibration curves over the range from 2.0 to 125 μg/L. The limits of detection (LOD) for all enantiomers in the soil and water were less than 1.8 μg/kg or μg/L, whereas the limit of quantification (LOQ) did not exceed 5.0 μg/kg or μg/L. The results of the method validation confirm that this proposed method is convenient and reliable for the enantioselective determination of the enantiomers of 9 chiral pesticides in soil and water. Copyright © 2013 Elsevier B.V. All rights reserved.

PEGylation of magnetic multi-walled carbon nanotubes for enhanced selectivity of dispersive solid phase extraction.

PubMed

Zeng, Qiong; Liu, Yi-Ming; Jia, Yan-Wei; Wan, Li-Hong; Liao, Xun

2017-02-01

Carbon nanotubes (CNTs) possess large potential as extraction absorbents in solid phase extraction. They have been widely applied in biomedicine research, while very rare application in natural product chemistry has been reported. In this work, methoxypolyethylene glycol amine (mPEG-NH 2 ) is covalently coupled to CNTs-magnetic nanoparticles (CNTs-MNP) to prepare a novel magnetic nanocomposite (PEG-CNTs-MNP) for use as dispersive solid-phase extraction (DSPE) absorbent. The average particle size was 86nm, and the saturation magnetization was 52.30emu/g. This nanocomposite exhibits excellent dispersibility in aqueous systems, high selectivity and fast binding kinetics when used for extraction of Z-ligustilide, the characteristic bioactive compound from two popular Asian herbal plants, R. chuanxiong and R. ligusticum. HPLC quantification of Z-ligustilide extracted from the standard sample solution showed a high recovery of 98.9%, and the extraction rate from the extracts of the above two herbs are both around 70.0%. To our knowledge, this is the first report on using PEG-CNTs-MNP as DSPE nanosorbents for selective extraction of natural products. This nano-material has promising application in isolation and enrichment of targeted components from complex matrices. Copyright © 2016 Elsevier B.V. All rights reserved.

Carbon nanotube-based benzyl polymethacrylate composite monolith as a solid phase extraction adsorbent and a stationary phase material for simultaneous extraction and analysis of polycyclic aromatic hydrocarbon in water.

PubMed

Al-Rifai, Asma'a; Aqel, Ahmad; Wahibi, Lamya Al; ALOthman, Zeid A; Badjah-Hadj-Ahmed, Ahmed-Yacine

2018-02-02

A composite of multi-walled carbon nanotubes incorporated into a benzyl methacrylate-co-ethylene dimethacrylate porous monolith was prepared, characterized and used as solid phase adsorbent and as stationary phase for simultaneous extraction and separation of ten polycyclic aromatic hydrocarbons, followed by nano-liquid chromatography analysis. The extraction and chromatographic parameters were optimized with regard to the extraction efficiency and the quality of chromatographic analytes separation. Under the optimized conditions, all PAHs were separated in 13 min with suitable resolution values (Rs = 1.74-3.98). Addition of a small amount of carbon nanotubes (0.1% with respect to monomers) to the polymerization mixture increased the efficiency for the separation column to over 41,700 plates m -1 for chrysene at flow rate of 0.5 μL min -1 . The method showed a wide linear range (1-500 μg L -1 with R 2 more than 0.9938), acceptable extraction repeatability (RSDs < 6.4%, n = 3) and reproducibility (RSDs < 12.6%, five parallel-made solid phase extraction cartridges) and satisfactory detection limits (0.02-0.22 μg L -1 ). Finally, the proposed method was successfully applied to the detection of polycyclic aromatic hydrocarbons in environmental water samples. After a simple extraction procedure with preconcentration factor equal to 100, the average recovery values in ultra-pure, tap and sea water samples were found to be in the range 81.3-95.4% with %RSD less than 6.4. Again, the presence of carbon nanotubes (0.3% relatively to monomers) in native polymer enhanced the extraction performance for the solid phase adsorbent up to 78.4%. The application of the monoliths modified with CNTs in extraction and nano-scale liquid chromatography for analysis of environmental samples offered several advantages; it demonstrated an acceptable precision, low detection limits, good reproducibility, satisfying recoveries and wide dynamic linear ranges. Copyright © 2018. Published by Elsevier B.V.

Determination of thiamethoxam residues in banana stem and fruit through LC-MS/MS.

PubMed

Suganthi, A; Nikita, S A; Kousika, J; Bhuvaneswari, K; Sridharan, S

2018-04-18

An analytical method based on liquid chromatography coupled with mass spectroscopy/mass spectroscopy was developed and validated for the determination of thiamethoxam residues in banana fruit and stem tissue samples. In this study, Waters Alliance LC and Acquity TQD were used with an electrospray ionization interface in the positive ion mode. An isocratic flow of 0.5% HCOOH in water and 0.05% HCOOH in CH 3 CN was used for separation. Thiamethoxam residue was extracted from the samples using CH 3 CN and a dispersive solid-phase extraction method was used for subsequent cleanup. Linearity studies were conducted between 0.001 and 0.1 μg mL -1 of standard solution with three replicates for each concentration. Satisfactory recoveries (107.21 to 115.16% and 90.94 to 109.22%) and high precision (relative standard deviations of 3.71 to 12.83% and 3.24 to 10.78%) were obtained for the banana stem and banana fruit matrix, respectively. The lower limits of detection and quantification achieved were 0.002 and 0.008 μg g -1 for banana stem and 0.001and 0.005 μg g -1 for banana fruit, respectively. The developed method was used to analyze the banana stem and fruit samples collected from thiamethoxam-treated fields and stems from the local market.

Vortex-assisted magnetic β-cyclodextrin/attapulgite-linked ionic liquid dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography for the fast determination of four fungicides in water samples.

PubMed

Yang, Miyi; Xi, Xuefei; Wu, Xiaoling; Lu, Runhua; Zhou, Wenfeng; Zhang, Sanbing; Gao, Haixiang

2015-02-13

A novel microextraction technique combining magnetic solid-phase microextraction (MSPME) with ionic liquid dispersive liquid-liquid microextraction (IL-DLLME) to determine four fungicides is presented in this work for the first time. The main factors affecting the extraction efficiency were optimized by the one-factor-at-a-time approach and the impacts of these factors were studied by an orthogonal design. Without tedious clean-up procedure, analytes were extracted from the sample to the adsorbent and organic solvent and then desorbed in acetonitrile prior to chromatographic analysis. Under the optimum conditions, good linearity and high enrichment factors were obtained for all analytes, with correlation coefficients ranging from 0.9998 to 1.0000 and enrichment factors ranging 135 and 159 folds. The recoveries for proposed approach were between 98% and 115%, the limits of detection were between 0.02 and 0.04 μg L(-1) and the RSDs changed from 2.96 to 4.16. The method was successfully applied in the analysis of four fungicides (azoxystrobin, chlorothalonil, cyprodinil and trifloxystrobin) in environmental water samples. The recoveries for the real water samples ranged between 81% and 109%. The procedure proved to be a time-saving, environmentally friendly, and efficient analytical technique. Copyright © 2015 Elsevier B.V. All rights reserved.

Kinetics of diuron under aerobic condition and residue analysis in sugarcane under subtropical field conditions.

PubMed

Tandon, Shishir; Pant, Ravi

2017-10-10

The phenylureas group includes persistent herbicides which are major pollutants to soil and water. Dissipation kinetics of diuron in different soils under sugarcane field conditions was investigated. Diuron was extracted with acetone and florisil solid phase extraction clean-up and characterized by high-performance liquid chromatography-UV. Diuron persisted for more than 100 days and dissipation followed monophasic first-order kinetics. Persistence was more in sandy loam compared to silty clay loam soil. Half-life of diuron in silty clay loam soil was 22.57 and 32.37 days and in sandy loam was 28.35 and 43.93 days at 2 and 4 kg ha-1applications, respectively. Average recovery in soil, bagasse, leaf-straw and juice ranged from 75.95% to 84.20%, 80.15% to 89.35%, 77.46% to 86.19% and 81.88% to 92.68%, respectively. The quantitation limits for soil, bagasse, leaf-straw and juice were 0.01, 0.03, 0.04 μg g -1 and 0.008 μg mL -1 , respectively. Application of diuron inhibited growth of soil microbes initially but they recovered later. At harvest, diuron residues were below maximum residue limits in all samples. The study revealed that under subtropical conditions, diuron is safe for use in weed management and would not pose any residual/environmental problem and that sugarcane crop could be used safe for human/animal consumption.

Quantitative determination of four nitrofuran metabolites in meat by isotope dilution liquid chromatography-electrospray ionisation-tandem mass spectrometry.

PubMed

Mottier, Pascal; Khong, Seu-Ping; Gremaud, Eric; Richoz, Janique; Delatour, Thierry; Goldmann, Till; Guy, Philippe A

2005-03-04

A confirmatory method based on isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been developed for the low-level determination of residues of four nitrofuran veterinary drugs in meat, e.g., furazolidone, furaltadone, nitrofurantoin, and nitrofurazone. The procedure entails an acid-catalysed release of protein-bound metabolites, followed by their in situ conversion into the 2-nitrobenzaldehyde (NBA) imine-type derivatives. Liquid-liquid extraction and clean-up on a polymeric solid phase extraction cartridge are then performed before LC-MS/MS analysis by positive electrospray ionisation (ESI) applying multiple reaction monitoring of three transition reactions for each compound. Reliable quantitation is obtained by using one deuterated analogue per analyte (d4-NBA derivative) as internal standard (IS). Validation of the method in chicken meat was conducted following the European Union (EU) criteria for the analysis of veterinary drug residues in foods. The decision limits (CCalpha) were 0.11-0.21 microg/kg, and the detection capabilities (CCbeta) 0.19-0.36 microg/kg, thus below the minimum required performance limit (MRPL) set at 1 microg/kg by the EU. The method is robust and suitable for routine quality control operations, and more than 200 sample injections were performed without excessive pollution of the mass spectrometer or loss of LC column performance.

Conventional sample enrichment strategies combined with high-performance liquid chromatography-solid phase extraction-nuclear magnetic resonance analysis allows analyte identification from a single minuscule Corydalis solida plant tuber.

PubMed

Sturm, Sonja; Seger, Christoph; Godejohann, Markus; Spraul, Manfred; Stuppner, Hermann

2007-09-07

Identification of putative biomarker molecules within the genus Corydalis (Papaveraceae) was pursued by combining conventional off-line sample enrichment with high-performance liquid chromatography-solid phase extraction-nuclear magnetic resonance (HPLC-SPE-NMR) based structure elucidation. Off-line reversed phase solid phase extraction (SPE) was used to enrich the desired analytes from a methanolic extract (93 mg dry weight) of a miniscule single tuber (233 mg dry weight) of C. solida. An aliquot of the SPE fraction (2.1 mg) was subjected to separation in the HPLC-SPE-NMR hyphenation. Chromatographic peaks bearing the metabolites under investigation were trapped in the SPE device in a single experiment and transferred to a 600 MHz NMR spectrometer equipped with a 30 microl cryofit insert fed into a 3 mm cryoprobe. Recorded homo- and heteronuclear 1D and 2D NMR data allowed the identification of the three analytes under investigation as protopine, allocryptopine, and N-methyl-laudanidinium acetate. The latter is a rare alkaloid, which has been isolated only once before.

Solid-phase extraction assisted dispersive liquid-liquid microextraction based on solidification of floating organic droplet to determine sildenafil and its analogues in dietary supplements.

PubMed

Li, Jing; Roh, Si Hun; Shaodong, Jia; Hong, Ji Yeon; Lee, Dong-Kyu; Shin, Byong-Kyu; Park, Jeong Hill; Lee, Jeongmi; Kwon, Sung Won

2017-08-01

A novel analytical method for the simultaneous determination of the concentration of sildenafil and its five analogues in dietary supplements using solid-phase extraction assisted reversed-phase dispersive liquid-liquid microextraction based on solidification of floating organic droplet combined with ion-pairing liquid chromatography with an ultraviolet detector was developed. Parameters that affect extraction efficiency were systematically investigated, including the type of solid-phase extraction cartridge, pH of the extraction environment, and the type and volume of extraction and dispersive solvent. The method linearity was in the range of 5.0-100 ng/mL for sildenafil, homosildenafil, udenafil, benzylsildenafil, and thiosildenafil and 10-100 ng/mL for acetildenafil. The coefficients of determination were ≥0.996 for all regression curves. The sensitivity values expressed as limit of detection were between 2.5 and 7.5 ng/mL. Furthermore, intraday and interday precisions expressed as relative standard deviations were less than 5.7 and 9.9%, respectively. The proposed method was successfully applied to the analysis of sildenafil and its five analogues in complex dietary supplements. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fully automated method for the liquid chromatographic determination of cyproterone acetate in plasma using restricted access material for sample pre-treatment.

PubMed

Christiaens, B; Chiap, P; Rbeida, O; Cello, D; Crommen, J; Hubert, Ph

2003-09-25

A new fully automated method for the quantitative analysis of an antiandrogenic substance, cyproterone acetate (CPA), in plasma samples has been developed using on-line solid-phase extraction (SPE) prior to the determination by reversed-phase liquid chromatography (LC). The automated method was based on the use of a precolumn packed with an internal-surface reversed-phase packing material (LiChrospher RP-4 ADS) for sample clean-up coupled to LC analysis on an octadecyl stationary phase using a column-switching system. A 200-microL volume of plasma sample was injected directly on the precolumn packed with restricted access material using a mixture of water-acetonitrile (90:10, v/v) as washing liquid. The analyte was then eluted in the back-flush mode with the LC mobile phase which consisted of a mixture of phosphate buffer, pH 7.0-acetonitrile (54:46, v/v). The elution profiles of CPA and blank plasma samples on the precolumn and the time needed for analyte transfer from the precolumn to the analytical column were determined. Different compositions of washing liquid and mobile phase were tested to reduce the interference of plasma endogenous components. UV detection was achieved at 280 nm. Finally, the developed method was validated using a new approach, namely the application of the accuracy profile based on the interval confidence at 90% of the total measurement error (bias+standard deviation). The limit of quantification of cyproterone acetate in plasma was determined at 15 ng mL(-1). The validated method should be applicable to the determination of CPA in patients treated by at least 50 mg day(-1).

Identification of Explosives from Porous Materials: Applications Using Reverse Phase High Performance Liquid Chromatography and Gas Chromatography

DOE Office of Scientific and Technical Information (OSTI.GOV)

C.J. Miller; G. Elias; N.C. Schmitt

2010-06-01

High performance liquid chromatography and gas chromatography techniques are well documented and widely used for the detection of trace explosives from organic solvents. These techniques were modified to specifically identify and quantify explosives extracted from various materials taken from people who had recently handled explosives. Documented techniques were modified to specifically detect and quantify RDX, TNT, and PETN from denim, colored flannel, vinyl, and canvas extracted in methanol using no sample cleanup prior to analysis. The methanol extracts were injected directly into several different column types and analyzed by HPLC-UV and/or GC-ECD. This paper describes general screening methods that weremore » used to determine the presence of explosives in unknown samples and techniques that have been optimized for quantification of each explosive from the substrate extracts.« less

Development and Efficacy Testing of Next Generation Cyanide Antidotes

DTIC Science & Technology

2013-10-01

Preparation of mDMTS A-2.2. HPLC method for DMTS determination in Micelles A-2.3. Head-space solid phase micro-extraction- gas chromatography -mass...Simultaneous determination of cyanide and thiocyanate in plasma by chemical ionization gas chromatography mass-spectrometry (CI-GC-MS). Analytical and...min. Peak integration was performed using Star Chromatography Workstation Version 6.20. A-2.3. Head-space solid phase micro-extraction- gas

Analysis of trifluralin, methyl paraoxon, methyl parathion, fenvalerate and 2,4-D dimethylamine in pond water using solid-phase extraction

USGS Publications Warehouse

Swineford, D.M.; Belisle, A.A.

1989-01-01

A method was developed for the simultaneous extraction of trifluralin, methyl paraoxon, methyl parathion, fenvalerate, and 2,4-D dimethylamine salt in pond water using a solid-phase C18 column. After elution from the C18 column, the eluate was analyzed on a capillary gas chromatograph equipped with an electron-capture or flame photometric detector.

EVALUATION OF SOLID PHASE MICROEXTRACTION FOR THE ANALYSIS OF HYDROPHILIC COMPOUNDS

EPA Science Inventory

Two commercially available solid phase microextractions (SPME) fibers, polyacrylate and carboxem/polydimethylsiloxane (PDMS), were evaluated for their ability to extract hydrophilic compounds from drinking water. Conditions, such as desorption time, desorption temperature, sample...

Electro-assisted solid-phase microextraction based on poly(3,4-ethylenedioxythiophen) combined with GC for the quantification of tricyclic antidepressants.

PubMed

Davarani, Saied Saeed Hosseiny; Nojavan, Saeed; Asadi, Roghayeh; Banitaba, Mohammad Hossein

2013-07-01

In this study, a platinum wire coated with poly(3,4-ethylenedioxythiophen) was used as an electro-assisted solid-phase microextraction fiber for the quantification of tricyclic antidepressant drugs in biological samples by coupling to GC employing a flame ionization detector. In this study, an electric field increased the extraction rate and recovery. The fiber used as a solid phase was synthesized by the electropolymerization of 3,4-ethylenedioxythiophen monomers onto a platinum wire. The ability of this fiber to extract imipramine, desipramine, and clomipramine by using the electro-assisted solid-phase microextraction technique was evaluated. The effect of various parameters that influence the extraction efficiency, which include solution temperature, extraction time, stirring rate, ionic strength, time and temperature of desorption, and thickness of the fiber, was optimized. Under optimized conditions, the linear ranges and regression coefficients of calibration curves were in the range of 0.5-250 and 0.990-0.998 ng/mL, respectively. Detection limits were in the range of 0.15-0.45 ng/mL. Finally, this method was applied to the determination of drugs in urine and wastewater samples and recoveries were 4.8-108.9%. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of heterocyclic aromatic amines (HAs) content in samples of household-prepared meat dishes.

PubMed

Warzecha, L; Janoszka, B; Błaszczyk, U; Strózyk, M; Bodzek, D; Dobosz, C

2004-03-25

Aminoazaarene content was investigated in 10 meat samples (including pork, beef, turey and chicken) thermally processed at home according to common recipes used by residents of Upper Silesia region in Poland. The clean-up procedure included tandem solid-phase extraction (SPE) using Extrelut-type columns filled with diatomaceous earth, propylsulphonic acid and chemically bounded phase-C18. Identification and quantitative analysis of HAs fraction was carried out using a HPLC system with DAD-type detector. Separation was achieved using TSK-gel ODS 80-TM column and a mixture of 5% acetonitrile and 95% triethylamine phosphate buffer (pH 3.3) as a mobile phase. The results of qualitative determinations were confirmed by GC-MS method. To achieve this, HAs fractions were derivatized to pentafluoropropionic acid (PFPA) amide derivatives. The summary content of five aminoazaarenes determined in investigated meat samples, i.e. 2-amino-3-methylimidazo [4,5-f]quinoline (IQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx), 2-amino-1-methyl-6-phenyl-imidazo[4,5-b]pyridine (PhIP) falls within the range of 1.9-77.4 ng/g of sample. The calculated values of theoretically daily human exposure to five determined HAs were in the range of 0.2-7.7 microg per day per person.

Application of micro-solid-phase extraction for the on-site extraction of heterocyclic aromatic amines in seawater.

PubMed

Basheer, Chanbasha

2018-04-01

An efficient on-site extraction technique to determine carcinogenic heterocyclic aromatic amines in seawater has been reported. A micro-solid-phase extraction device placed inside a portable battery-operated pump was used for the on-site extraction of seawater samples. Before on-site applications, parameters that influence the extraction efficiency (extraction time, type of sorbent materials, suitable desorption solvent, desorption time, and sample volume) were investigated and optimized in the laboratory. The developed method was then used for the on-site sampling of heterocyclic aromatic amines determination in seawater samples close to distillation plant. Once the on-site extraction completed, the small extraction device with the analytes was brought back to the laboratory for analysis using high-performance liquid chromatography with fluorescence detection. Based on the optimized conditions, the calibration curves were linear over the concentration range of 0.05-20 μg/L with correlation coefficients up to 0.996. The limits of detection were 0.004-0.026 μg/L, and the reproducibility values were between 1.3 and 7.5%. To evaluate the extraction efficiency, a comparison was made with conventional solid-phase extraction and it was applied to various fortified real seawater samples. The average relative recoveries obtained from the spiked seawater samples varied in the range 79.9-95.2%. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A modified extraction and clean-up procedure for the detection and determination of parathion-methyl and chlorpyrifos residues in tea.

PubMed

Shanker, A; Sood, C; Kumar, V; Ravindranath, S D

2001-05-01

Recent advances in methodology and instrumentation have made possible the detection and determination of pesticides at microgram kg-1 (ppb) levels. The sensitivity of a method of analysis depends greatly on the efficient extraction of the pesticide and the subsequent clean-up of the extract. The extract from green tea leaves is a mixture of aroma components, polyphenols and caffeine. The preparation of made tea from green tea leaves adds to this complexity by concentrating these coextractives. Conventional clean-up techniques provide poor recoveries for parathion-methyl and chlorpyrifos from both green tea leaves and made tea. This arises from interference by caffeine during gas chromatography, as it has a similar retention time to the two pesticides and peaks overlap. A modification to the protocol based on a solvent partitioning process using dichloromethane and subsequent washing of the extracts with warm water removed the caffeine, and pigments were removed by column chromatography. Recoveries ranging from 80 to 90% were then obtained for both pesticides.

Identification and measurement of beta-lactam antibiotic residues in milk: integration of screening kits with liquid chromatography.

PubMed

Harik-Khan, R; Moats, W A

1995-01-01

A procedure for identifying and quantitating violative beta-lactams in milk is described. This procedure integrates beta-lactam residue detection kits with the multiresidue automated liquid chromatographic (LC) cleanup method developed in our laboratory. Spiked milk was deproteinized, extracted, and subjected to reversed-phase LC using a gradient program that concentrated the beta-lactams. Amoxicillin, ampicillin, cephapirin, ceftiofur, cloxacillin, and penicillin G were, thus, separated into 5 fractions that were subsequently tested for activity by using 4 kits. beta-lactams in the positive fractions were quantitated by analytical LC methods developed in our laboratory. The LC cleanup method separated beta-lactam antibiotics from each other and from interferences in the matrix and also concentrated the antibiotics, thus increasing the sensitivity of the kits to the beta-lactam antibiotics. The procedure facilitated the task of identifying and measuring the beta-lactam antibiotics that may be present in milk samples.

Solid-phase extraction sorbent consisting of alkyltrimethylammonium surfactants immobilized onto strong cation-exchange polystyrene resin.

PubMed

Reid, Kendra R; Kennedy, Lonnie J; Crick, Eric W; Conte, Eric D

2002-10-25

Presented is a solid-phase extraction sorbent material composed of cationic alkyltrimethylammonium surfactants attached to a strong cation-exchange resin via ion-exchange. The original hydrophilic cation-exchange resin is made hydrophobic by covering the surface with alkyl chains from the hydrophobic portion of the surfactant. The sorbent material now has a better ability to extract hydrophobic molecules from aqueous samples. The entire stationary phase (alkyltrimethylammonium surfactant) is removed along with the analyte during the elution step. The elution step requires a mild elution solvent consisting of 0.25 M Mg2+ in a 50% 2-propanol solution. The main advantage of using a removable stationary phase is that traditionally utilized toxic elution solvents such as methylene chloride, which are necessary to efficiently release strongly hydrophobic species from SPE stationary phases, may now be avoided. Also, the final extract is directly compatible with reversed-phase liquid chromatography. The performance of this procedure is presented using pyrene as a test molecule.

Systematic Assessment of Seven Solvent and Solid-Phase Extraction Methods for Metabolomics Analysis of Human Plasma by LC-MS

NASA Astrophysics Data System (ADS)

Sitnikov, Dmitri G.; Monnin, Cian S.; Vuckovic, Dajana

2016-12-01

The comparison of extraction methods for global metabolomics is usually executed in biofluids only and focuses on metabolite coverage and method repeatability. This limits our detailed understanding of extraction parameters such as recovery and matrix effects and prevents side-by-side comparison of different sample preparation strategies. To address this gap in knowledge, seven solvent-based and solid-phase extraction methods were systematically evaluated using standard analytes spiked into both buffer and human plasma. We compared recovery, coverage, repeatability, matrix effects, selectivity and orthogonality of all methods tested for non-lipid metabolome in combination with reversed-phased and mixed-mode liquid chromatography mass spectrometry analysis (LC-MS). Our results confirmed wide selectivity and excellent precision of solvent precipitations, but revealed their high susceptibility to matrix effects. The use of all seven methods showed high overlap and redundancy which resulted in metabolite coverage increases of 34-80% depending on LC-MS method employed as compared to the best single extraction protocol (methanol/ethanol precipitation) despite 7x increase in MS analysis time and sample consumption. The most orthogonal methods to methanol-based precipitation were ion-exchange solid-phase extraction and liquid-liquid extraction using methyl-tertbutyl ether. Our results help facilitate rational design and selection of sample preparation methods and internal standards for global metabolomics.

Systematic Assessment of Seven Solvent and Solid-Phase Extraction Methods for Metabolomics Analysis of Human Plasma by LC-MS

PubMed Central

Sitnikov, Dmitri G.; Monnin, Cian S.; Vuckovic, Dajana

2016-01-01

The comparison of extraction methods for global metabolomics is usually executed in biofluids only and focuses on metabolite coverage and method repeatability. This limits our detailed understanding of extraction parameters such as recovery and matrix effects and prevents side-by-side comparison of different sample preparation strategies. To address this gap in knowledge, seven solvent-based and solid-phase extraction methods were systematically evaluated using standard analytes spiked into both buffer and human plasma. We compared recovery, coverage, repeatability, matrix effects, selectivity and orthogonality of all methods tested for non-lipid metabolome in combination with reversed-phased and mixed-mode liquid chromatography mass spectrometry analysis (LC-MS). Our results confirmed wide selectivity and excellent precision of solvent precipitations, but revealed their high susceptibility to matrix effects. The use of all seven methods showed high overlap and redundancy which resulted in metabolite coverage increases of 34–80% depending on LC-MS method employed as compared to the best single extraction protocol (methanol/ethanol precipitation) despite 7x increase in MS analysis time and sample consumption. The most orthogonal methods to methanol-based precipitation were ion-exchange solid-phase extraction and liquid-liquid extraction using methyl-tertbutyl ether. Our results help facilitate rational design and selection of sample preparation methods and internal standards for global metabolomics. PMID:28000704

Effects of a reactive barrier and aquifer geology on metal distribution and mobility in a mine drainage impacted aquifer.

PubMed

Doerr, Nora A; Ptacek, Carol J; Blowes, David W

2005-06-01

The Nickel Rim aquifer has been impacted for five decades by a metal-rich plume generated from the Nickel Rim mine tailings impoundment. Metals released by the oxidation of pyrrhotite in the unsaturated zone of the tailings migrate into the downgradient aquifer, affecting both the groundwater and the aquifer solids. A reactive barrier has been installed in the aquifer to remove sulfate and metals from the groundwater. The effect of the reactive barrier on metal concentrations in the aquifer solids has not previously been studied. In this study, a series of selective extraction procedures was applied to cores of aquifer sediment, to ascertain the distribution of metals among various solid phases present in the aquifer. Extraction results were combined with groundwater chemistry, geochemical modelling and solid-phase microanalyses, to assess the potential mobility of metals under changing geochemical conditions. Reactions within the reactive barrier caused an increase in the solid-phase carbonate content downgradient from the barrier. The concentrations of poorly crystalline, oxidized phases of Mn and Fe, as well as concentrations of Cr(III) associated with oxidized Fe, and poorly crystalline Zn, are lower downgradient from the barrier, whereas total solid-phase metal concentrations remain constant. Iron and Mn accumulate as oxidized, easily extractable forms in a peat layer overlying the aquifer. Although these oxides may buffer reducing plumes, they also have the potential to release metals to the groundwater, should a reduced condition be imposed on the aquifer by remedial actions.

Open Port Probe Sampling Interface for the Direct Coupling of Biocompatible Solid-Phase Microextraction to Atmospheric Pressure Ionization Mass Spectrometry.

PubMed

Gómez-Ríos, Germán Augusto; Liu, Chang; Tascon, Marcos; Reyes-Garcés, Nathaly; Arnold, Don W; Covey, Thomas R; Pawliszyn, Janusz

2017-04-04

In recent years, the direct coupling of solid phase microextraction (SPME) and mass spectrometry (MS) has shown its great potential to improve limits of quantitation, accelerate analysis throughput, and diminish potential matrix effects when compared to direct injection to MS. In this study, we introduce the open port probe (OPP) as a robust interface to couple biocompatible SPME (Bio-SPME) fibers to MS systems for direct electrospray ionization. The presented design consisted of minimal alterations to the front-end of the instrument and provided better sensitivity, simplicity, speed, wider compound coverage, and high-throughput in comparison to the LC-MS based approach. Quantitative determination of clenbuterol, fentanyl, and buprenorphine was successfully achieved in human urine. Despite the use of short extraction/desorption times (5 min/5 s), limits of quantitation below the minimum required performance levels (MRPL) set by the world antidoping agency (WADA) were obtained with good accuracy (≥90%) and linearity (R 2 > 0.99) over the range evaluated for all analytes using sample volumes of 300 μL. In-line technologies such as multiple reaction monitoring with multistage fragmentation (MRM 3 ) and differential mobility spectrometry (DMS) were used to enhance the selectivity of the method without compromising analysis speed. On the basis of calculations, once coupled to high throughput, this method can potentially yield preparation times as low as 15 s per sample based on the 96-well plate format. Our results demonstrated that Bio-SPME-OPP-MS efficiently integrates sampling/sample cleanup and atmospheric pressure ionization, making it an advantageous configuration for several bioanalytical applications, including doping in sports, in vivo tissue sampling, and therapeutic drug monitoring.

Methods of Analysis - Determination of Pyrethroid Insecticides in Water and Sediment Using Gas Chromatography/Mass Spectrometry

USGS Publications Warehouse

Hladik, Michelle; Smalling, Kelly L.; Kuivila, Kathryn

2009-01-01

A method for the determination of 14 pyrethroid insecticides in environmental water and sediment samples is described. The method was developed by the U.S. Geological Survey in response to increasing concern over the effects of pyrethroids on aquatic organisms. The pyrethroids included in this method are ones that are applied to many agricultural and urban areas. Filtered water samples are extracted for pyrethroids using solid-phase extraction (SPE) with no additional cleanup steps. Sediment and soil samples are extracted using a microwave-assisted extraction system, and the pyrethroids of interest are separated from co-extracted matrix interferences by passing the extracts through stacked graphitized carbon and alumina SPE cartridges, along with the use of high-performance liquid chromatography and gel-permeation chromatography (HPLC/GPC). Quantification of the pyrethroids from the extracted water and sediment samples is done using gas chromatography with mass spectrometry (GC/MS) or gas chromatography with tandem mass spectrometry (GC/MS/MS). Recoveries in test water samples fortified at 10 ng/L ranged from 83 to 107 percent, and recoveries in test sediment samples fortified at 10 ug/kg ranged from 82 to 101 percent; relative standard deviations ranged from 5 to 9 percent in the water samples and 3 to 9 percent in the sediment samples. Method detection limits (MDLs), calculated using U.S. Environmental Protection Agency procedures (40 CFR 136, Appendix B), in water ranged from 2.0 to 6.0 ng/L using GC/MS and 0.5 to 1.0 ng/L using GC/MS/MS. For sediment, the MDLs ranged from 1.0 to 2.6 ug/kg dry weight using GC/MS and 0.2 to 0.5 ug/kg dry weight using GC/MS/MS. The matrix-spike recoveries for each compound, when averaged for 12 environmental water samples, ranged from 84 to 96 percent, and when averaged for 27 environmental sediment samples, ranged from 88 to 100 percent.

Simple method for the determination of personal care product ingredients in lettuce by ultrasound-assisted extraction combined with solid-phase microextraction followed by GC-MS.

PubMed

Cabrera-Peralta, Jerónimo; Peña-Alvarez, Araceli

2018-05-01

A simple method for the simultaneous determination of personal care product ingredients: galaxolide, tonalide, oxybenzone, 4-methylbenzyliden camphor, padimate-o, 2-ethylhexyl methoxycinnamate, octocrylene, triclosan, and methyl triclosan in lettuce by ultrasound-assisted extraction combined with solid-phase microextraction followed by gas chromatography with mass spectrometry was developed. Lettuce was directly extracted by ultrasound-assisted extraction with methanol, this extract was combined with water, extracted by solid-phase microextraction in immersion mode, and analyzed by gas chromatography with mass spectrometry. Good linear relationships (25-250 ng/g, R 2  > 0.9702) and low detection limits (1.0-25 ng/g) were obtained for analytes along with acceptable precision for almost all analytes (RSDs < 20%). The validated method was applied for the determination of personal care product ingredients in commercial lettuce and lettuces grown in soil and irrigated with the analytes, identifying the target analytes in leaves and roots of the latter. This procedure is a miniaturized and environmentally friendly proposal which can be a useful tool for quality analysis in lettuce. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An enhanced procedure for measuring organic acids and methyl esters in PM2.5

NASA Astrophysics Data System (ADS)

Liu, F.; Duan, F. K.; He, K. B.; Ma, Y. L.; Rahn, K. A.; Zhang, Q.

2015-11-01

A solid-phase extraction (SPE) pretreatment procedure allowing organic acids to be separated from methyl esters in fine aerosol has been developed. The procedure first separates the organic acids from fatty acid methyl esters (FAMEs) and other nonacid organic compounds by aminopropyl-based SPE cartridge and then quantifies them by gas chromatography/mass spectrometry. The procedure prevents the fatty acids and dimethyl phthalate from being overestimated, and so allows us to accurately quantify the C4-C11 dicarboxylic acids (DCAs) and the C8-C30 monocarboxylic acids (MCAs). Results for the extraction of DCAs, MCAs, and AMAs in eluate and FAMEs in effluate by SAX and NH2 SPE cartridges exhibited that the NH2 SPE cartridge gave higher extraction efficiency than the SAX cartridge. The recoveries of analytes ranged from 67.5 to 111.3 %, and the RSD ranged from 0.7 to 10.9 %. The resulting correlations between the aliphatic acids and FAMEs suggest that the FAMEs had sources similar to those of the carboxylic acids, or were formed by esterifying carboxylic acids, or that aliphatic acids were formed by hydrolyzing FAMEs. Through extraction and cleanup using this procedure, 17 aromatic acids in eluate were identified and quantified by gas chromatography/tandem mass spectrometry, including five polycyclic aromatic hydrocarbon (PAH): acids 2-naphthoic, biphenyl-4-carboxylic, 9-oxo-9H-fluorene-1-carboxylic, biphenyl-4,4´-dicarboxylic, and phenanthrene-1-carboxylic acid, plus 1,8-naphthalic anhydride. Correlations between the PAH acids and the dicarboxylic and aromatic acids suggested that the first three acids and 1,8-naphthalic anhydride were secondary atmospheric photochemistry products and the last two mainly primary.

Modification and re-validation of the ethyl acetate-based multi-residue method for pesticides in produce

PubMed Central

Rooseboom, Astrid; van Dam, Ruud; Roding, Marleen; Arondeus, Karin; Sunarto, Suryati

2007-01-01

The ethyl acetate-based multi-residue method for determination of pesticide residues in produce has been modified for gas chromatographic (GC) analysis by implementation of dispersive solid-phase extraction (using primary–secondary amine and graphitized carbon black) and large-volume (20 μL) injection. The same extract, before clean-up and after a change of solvent, was also analyzed by liquid chromatography with tandem mass spectrometry (LC–MS–MS). All aspects related to sample preparation were re-assessed with regard to ease and speed of the analysis. The principle of the extraction procedure (solvent, salt) was not changed, to avoid the possibility invalidating data acquired over past decades. The modifications were made with techniques currently commonly applied in routine laboratories, GC–MS and LC–MS–MS, in mind. The modified method enables processing (from homogenization until final extracts for both GC and LC) of 30 samples per eight hours per person. Limits of quantification (LOQs) of 0.01 mg kg−1 were achieved with both GC–MS (full-scan acquisition, 10 mg matrix equivalent injected) and LC–MS–MS (2 mg injected) for most of the pesticides. Validation data for 341 pesticides and degradation products are presented. A compilation of analytical quality-control data for pesticides routinely analyzed by GC–MS (135 compounds) and LC–MS–MS (136 compounds) in over 100 different matrices, obtained over a period of 15 months, are also presented and discussed. At the 0.05 mg kg−1 level acceptable recoveries were obtained for 93% (GC–MS) and 92% (LC–MS–MS) of pesticide–matrix combinations. PMID:17563885

A METHOD FOR AUTOMATED ANALYSIS OF 10 ML WATER SAMPLES CONTAINING ACIDIC, BASIC, AND NEUTRAL SEMIVOLATILE COMPOUNDS LISTED IN USEPA METHOD 8270 BY SOLID PHASE EXTRACTION COUPLED IN-LINE TO LARGE VOLUME INJECTION GAS CHROMATOGRAPHY/MASS SPECTROMETRY

EPA Science Inventory

Data is presented showing the progress made towards the development of a new automated system combining solid phase extraction (SPE) with gas chromatography/mass spectrometry for the single run analysis of water samples containing a broad range of acid, base and neutral compounds...

Concentration of organic compounds in natural waters with solid-phase dispersion based on advesicle modified silica prior to liquid chromatography.

PubMed

Parisis, Nikolaos A; Giokas, Dimosthenis L; Vlessidis, Athanasios G; Evmiridis, Nicholaos P

2005-12-02

The ability of vesicle-coated silica to aid the extraction of organic compounds from water prior to liquid chromatographic analysis is presented for the first time. The method is based on the formation of silica supported cationic multi-lamellar vesicles of gemini surfactants inherently ensuring the presence of hydrophilic and hydrophobic sites for the partitioning of analytes bearing different properties. Method development is illustrated by studying the adsolubilization of UV absorbing chemicals from swimming pool water. Due to the requirement for external energy input (intense shearing) a method based on solid-phase dispersion (SPD) was applied producing better results than off-line solid-phase extraction (SPE). Meticulous investigation of the experimental parameters was conducted in order to elucidate the mechanisms behind the proposed extraction pattern. Analyte recoveries were quantitative under the optimum experimental conditions offering recoveries higher than 96% with RSD values below 5%.

Online solid-phase extraction with high-performance liquid chromatography and mass spectrometry for the determination of five tannins in traditional Chinese medicine injections.

PubMed

Sun, Meng; Lin, Yuanyuan; Zhang, Jie; Zheng, Shaohua; Wang, Sicen

2016-03-01

A rapid analytical method based on online solid-phase extraction with high-performance liquid chromatography and mass spectrometry has been established and applied to the determination of tannin compounds that may cause adverse effects in traditional Chinese medicine injections. Different solid-phase extraction sorbents have been compared and the elution buffer was optimized. The performance of the method was verified by evaluation of recovery (≥40%), repeatability (RSD ≤ 6%), linearity (r(2) ≥ 0.993), and limit of quantification (≤0.35 μg/mL). Five tannin compounds, gallic acid, cianidanol, gallocatechin gallate, ellagic acid, and penta-O-galloylglucose, were identified with concentrations ranging from 3.1-37.4 μg/mL in the analyzed traditional Chinese medicine injections. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solid-phase extraction NMR studies of chromatographic fractions of saponins from Quillaja saponaria.

PubMed

Nyberg, Nils T; Baumann, Herbert; Kenne, Lennart

2003-01-15

The saponin mixture QH-B from the tree Quillaja saponaria var. Molina was fractionated by RP-HPLC in several steps. The fractions were analyzed by solid-phase extraction NMR (SPE-NMR), a technique combining the workup by solid-phase extraction with on-line coupling to an NMR flow probe. Together with MALDI-TOF mass spectrometry and comparison with chemical shifts of similar saponins, the structures of both major and minor components in QH-B could be obtained. The procedure described is a simple method to determine the structure of components in a complex mixture. The two major fractions of the mixture were found to contain at least 28 saponins, differing in the carbohydrate substructures. Eight of these have not previously been determined. The 28 saponins formed 14 equilibrium pairs by the migration of an O-acyl group between two adjacent positions on a fucosyl residue.

A sol-gel based solid phase microextraction fiber for the analysis of aliphatic alcohols in apple juices.

PubMed

Farhadi, Khalil; Maleki, Ramin; Tahmasebi, Raheleh

2010-01-01

A new fiber based on titania-chitin sol-gel coated on a silver wire for the headspace solid phase microextraction of aliphatic alcohols from apple juice samples was developed. The influences of fiber coating composition and microextraction conditions (extraction temperature, extraction time, and ionic strength of the sample matrix) on the fiber performance were investigated. Also, the influence of temperature and time on desorption of analytes from fiber were studied. Under the optimized conditions, a porous fiber with a high extraction capacity and good thermal stability (up to 250 degrees C) was obtained. The proposed headspace solid-phase microextraction-GC method was successfully used for the analysis of aliphatic alcohols in apple juice and concentrate samples. The recovery values were from 92.8 to 98.6%. The RSD (n=5) for all analytes were below 7.8%.

Analysis of Explosives in Soil Using Solid Phase Microextraction and Gas Chromatography: Environmental Analysis

DTIC Science & Technology

2006-01-01

ENVIRONMENTAL ANALYSIS Analysis of Explosives in Soil Using Solid Phase Microextraction and Gas Chromatography Howard T. Mayfield Air Force Research...Abstract: Current methods for the analysis of explosives in soils utilize time consuming sample preparation workups and extractions. The method detection...chromatography/mass spectrometry to provide a con- venient and sensitive analysis method for explosives in soil. Keywords: Explosives, TNT, solid phase

Hollow fiber supported ionic liquid membrane microextraction for determination of sulfonamides in environmental water samples by high-performance liquid chromatography.

PubMed

Tao, Yong; Liu, Jing-Fu; Hu, Xia-Lin; Li, Hong-Cheng; Wang, Thanh; Jiang, Gui-Bin

2009-08-28

By using ionic liquid as membrane liquid and tri-n-octylphosphine oxide (TOPO) as additive, hollow fiber supported liquid phase microextraction (HF-LPME) was developed for the determination of five sulfonamides in environmental water samples by high-performance liquid chromatography with ultraviolet detection The extraction solvent and the parameters affecting the extraction enrichment factor such as the type and amount of carrier, pH and volume ratio of donor phase and acceptor phase, extraction time, salt-out effect and matrix effect were optimized. Under the optimal extraction conditions (organic liquid membrane phase: [C(8)MIM][PF(6)] with 14% TOPO (w/v); donor phase: 4mL, pH 4.5 KH(2)PO(4) with 2M Na(2)SO(4); acceptor phase: 25microL, pH 13 NaOH; extraction time: 8 h), low detection limits (0.1-0.4microg/L, RSDor=0.999) were obtained for all the analytes. The presence of humic acid (0-25mg/L dissolved organic carbon) and bovine serum albumin (0-100microg/mL) had no significant effect on the extraction efficiency. Good spike recoveries over the range of 82.2-103.2% were obtained when applying the proposed method on five real environmental water samples. These results indicated that this present method was very sensitive and reliable with good repeatabilities and excellent clean-up in water samples. The proposed method confirmed hollow fiber supported ionic liquid membrane based LPME to be robust to monitoring trace levels of sulfadiazine, sulfamerazine, sulfamethazine, sulfadimethoxine and sulfamethoxazole in aqueous samples.

Preparative isolation of flavonoid glycosides from Sphaerophysa salsula using hydrophilic interaction solid-phase extraction coupled with two-dimensional preparative liquid chromatography.

PubMed

Jiao, Lijin; Tao, Yanduo; Wang, Weidong; Shao, Yun; Mei, Lijuan; Wang, Qilan; Dang, Jun

2017-10-01

An offline preparative two-dimensional reversed-phase liquid chromatography/hydrophilic interaction liquid chromatography coupled with hydrophilic interaction solid-phase extraction method was developed for the preparative isolation of flavonoid glycosides from a crude sample of Sphaerophysa salsula. First, the non-flavonoids were removed using an XAmide solid-phase extraction cartridge. Based on the separation results of three different chromatographic stationary phases, the first-dimensional preparation was performed on an XAqua C18 prep column, and 15 fractions were obtained from the 5.2 g target sample. Then, three representative fractions were selected for additional purification on an XAmide preparative column to further isolate the flavonoid glycosides. In all, eight flavonoid glycosides were isolated in purities over 97%. The results demonstrated that the two-dimensional liquid chromatography method used in this study was effective for the preparative separation of flavonoid glycosides from Sphaerophysa salsula. Additionally, this method showed great potential for the separation of flavonoid glycosides from other plant materials. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Polyamide as an efficient sorbent for simultaneous interface-free determination of three Sudan dyes in saffron and urine using high-performance liquid chromatography-ultra violet detection.

PubMed

Saeidi, Iman; Barfi, Behruz; Payrovi, Moazameh; Feizy, Javid; Sheibani, Hojat A; Miri, Mina; Ghollasi Moud, Farahnaz

2015-01-01

With polyamide (PA) as an efficient sorbent for solid phase extraction (SPE) of Sudan dyes II, III and Red 7B from saffron and urine, their determination by HPLC was performed. The optimum conditions for SPE were achieved using 7 mL methanol/water (1:9, v/v, pH 7) as the washing solvent and 3 mL tetrahydrofuran for elution. Good clean-up and high (above 90%) recoveries were observed for all the analytes. The optimized mobile phase composition for HPLC analysis of these compounds was methanol-water (70:30, v/v). The SPE parameters, such as the maximum loading capacity and breakthrough volume, were also determined for each analyte. The limits of detection (LODs), limits of quantification (LOQs), linear ranges and recoveries for the analytes were 4.6-6.6 microg/L, 13.0-19.8 microg/L, 13.0-5000 microg/L (r2>0.99) and 92.5%-113.4%, respectively. The precisions (RSDs) of the overall analytical procedure, estimated by five replicate measurements for Sudan II, III and Red 7B in saffron and urine samples were 2.3%, 1.8% and 3.6%, respectively. The developed method is simple and successful in the application to the determination of Sudan dyes in saffron and urine samples with HPLC coupled with UV detection.

Ionic-liquid-based dispersive liquid-liquid microextraction combined with magnetic solid-phase extraction for the determination of aflatoxins B1 , B2 , G1 , and G2 in animal feeds by high-performance liquid chromatography with fluorescence detection.

PubMed

Zhao, Jiao; Zhu, Yan; Jiao, Yang; Ning, Jinyan; Yang, Yaling

2016-10-01

A novel two-step extraction technique combining ionic-liquid-based dispersive liquid-liquid microextraction with magnetic solid-phase extraction was developed for the preconcentration and separation of aflatoxins in animal feedstuffs before high-performance liquid chromatography coupled with fluorescence detection. In this work, ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate was used as the extractant in dispersive liquid-liquid microextraction, and hydrophobic pelargonic acid modified Fe 3 O 4 magnetic nanoparticles as an efficient adsorbent were applied to retrieve the aflatoxins-containing ionic liquid. Notably, the target of magnetic nanoparticles was the ionic liquid rather than the aflatoxins. Because of the rapid mass transfer associated with the dispersive liquid-liquid microextraction and magnetic solid phase steps, fast extraction could be achieved. The main parameters affecting the extraction recoveries of aflatoxins were investigated and optimized. Under the optimum conditions, vortexing at 2500 rpm for 1 min in the dispersive liquid-liquid microextraction and magnetic solid-phase extraction and then desorption by sonication for 2 min with acetonitrile as eluent. The recoveries were 90.3-103.7% with relative standard deviations of 3.2-6.4%. Good linearity was observed with correlation coefficients ranged from 0.9986 to 0.9995. The detection limits were 0.632, 0.087, 0.422 and 0.146 ng/mL for aflatoxins B 1 , B2, G1, and G2, respectively. The results were also compared with the pretreatment method carried out by conventional immunoaffinity columns. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solid-phase extraction using bis(indolyl)methane-modified silica reinforced with multiwalled carbon nanotubes for the simultaneous determination of flavonoids and aromatic organic acid preservatives.

PubMed

Wang, Na; Liao, Yuan; Wang, Jiamin; Tang, Sheng; Shao, Shijun

2015-12-01

A novel bis(indolyl)methane-modified silica reinforced with multiwalled carbon nanotubes sorbent for solid-phase extraction was designed and synthesized by chemical immobilization of nitro-substituted 3,3'-bis(indolyl)methane on silica modified with multiwalled carbon nanotubes. Coupled with high-performance liquid chromatography analysis, the extraction properties of the sorbent were evaluated for flavonoids and aromatic organic acid compounds. Under optimum conditions, the sorbent can simultaneously extract five flavonoids and two aromatic organic acid preservatives in aqueous solutions in a single-step solid-phase extraction procedure. Wide linear ranges were obtained with correlation coefficients (R(2) ) ranging from 0.9843 to 0.9976, and the limits of detection were in the range of 0.5-5 μg/L for the compounds tested. Compared with the silica modified with multiwalled carbon nanotubes sorbent and the nitro-substituted 3,3'-bis(indolyl)methane-modified silica sorbent, the developed sorbent exhibited higher extraction efficiency toward the selected analytes. The synergistic effect of nitro-substituted 3,3'-bis(indolyl)methane and multiwalled carbon nanotubes not only improved the surface-to-volume ratio but also enhanced multiple intermolecular interactions, such as hydrogen bonds, π-π, and hydrophobic interactions, between the new sorbent and the selected analytes. The as-established solid-phase extraction with high-performance liquid chromatography and diode array detection method was successfully applied to the simultaneous determination of flavonoids and aromatic organic acid preservatives in grape juices with recoveries ranging from 83.9 to 112% for all the selected analytes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.