Determination of Aroclor 1260 in soil samples by gas chromatography with mass spectrometry and solid-phase microextraction.

PubMed

Zhang, Mengliang; Jackson, Glen P; Kruse, Natalie A; Bowman, Jennifer R; Harrington, Peter de B

2014-10-01

A novel fast screening method was developed for the determination of polychlorinated biphenyls that are constituents of the commercial mixture, Aroclor 1260, in soil matrices by gas chromatography with mass spectrometry combined with solid-phase microextraction. Nonequilibrium headspace solid-phase microextraction with a 100 μm polydimethylsiloxane fiber was used to extract polychlorinated biphenyls from 0.5 g of soil matrix. The use of 2 mL of saturated potassium dichromate in 6 M sulfuric acid solution improved the reproducibility of the extractions and the mass transfer of the polychlorinated biphenyls from the soil matrix to the microextraction fiber via the headspace. The extraction time was 30 min at 100°C. The percent recoveries, which were evaluated using an Aroclor 1260 standard and liquid injection, were within the range of 54.9-65.7%. Two-way extracted ion chromatogram data were used to construct calibration curves. The relative error was <±15% and the relative standard deviation was <15%, which are respective measures of the accuracy and precision. The method was validated with certified soil samples and the predicted concentrations for Aroclor 1260 agreed with the certified values. The method was demonstrated to be linear from 10 to 1000 ng/g for Aroclor 1260 in dry soil. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An Effective Method to Detect Volatile Intermediates Generated in the Bioconversion of Coal to Methane by Gas Chromatography-Mass Spectrometry after In-Situ Extraction Using Headspace Solid-Phase Micro-Extraction under Strict Anaerobic Conditions.

PubMed

Liu, Jianmin; Wang, Baoyu; Tai, Chao; Wu, Li; Zhao, Han; Guan, Jiadong; Chen, Linyong

2016-01-01

Bioconversion of coal to methane has gained increased attention in recent decades because of its economic and environmental advantages. However, the mechanism of this process is difficult to study in depth, partly because of difficulties associated with the analysis of intermediates generated in coal bioconversion. In this investigation, we report on an effective method to analyze volatile intermediates generated in the bioconversion of coal under strict anaerobic conditions. We conduct in-situ extraction of intermediates using headspace solid-phase micro-extraction followed by detection by gas chromatography-mass spectrometry. Bioconversion simulation equipment was modified and combined with a solid-phase micro-extraction device. In-situ extraction could be achieved by using the combined units, to avoid a breakdown in anaerobic conditions and to maintain the experiment continuity. More than 30 intermediates were identified qualitatively in the conversion process, and the variation in trends of some typical intermediates has been discussed. Volatile organic acids (C2-C7) were chosen for a quantitative study of the intermediates because of their importance during coal bioconversion to methane. Fiber coating, extraction time, and solution acidity were optimized in the solid-phase micro-extraction procedure. The pressure was enhanced during the bioconversion process to investigate the influence of headspace pressure on analyte extraction. The detection limits of the method ranged from 0.0006 to 0.02 mmol/L for the volatile organic acids and the relative standard deviations were between 4.6% and 11.5%. The volatile organic acids (C2-C7) generated in the bioconversion process were 0.01-1.15 mmol/L with a recovery range from 80% to 105%. The developed method is useful for further in-depth research on the bioconversion of coal to methane.

An Effective Method to Detect Volatile Intermediates Generated in the Bioconversion of Coal to Methane by Gas Chromatography-Mass Spectrometry after In-Situ Extraction Using Headspace Solid-Phase Micro-Extraction under Strict Anaerobic Conditions

PubMed Central

Liu, Jianmin; Wang, Baoyu; Tai, Chao; Wu, Li; Zhao, Han; Guan, Jiadong; Chen, Linyong

2016-01-01

Bioconversion of coal to methane has gained increased attention in recent decades because of its economic and environmental advantages. However, the mechanism of this process is difficult to study in depth, partly because of difficulties associated with the analysis of intermediates generated in coal bioconversion. In this investigation, we report on an effective method to analyze volatile intermediates generated in the bioconversion of coal under strict anaerobic conditions. We conduct in-situ extraction of intermediates using headspace solid-phase micro-extraction followed by detection by gas chromatography-mass spectrometry. Bioconversion simulation equipment was modified and combined with a solid-phase micro-extraction device. In-situ extraction could be achieved by using the combined units, to avoid a breakdown in anaerobic conditions and to maintain the experiment continuity. More than 30 intermediates were identified qualitatively in the conversion process, and the variation in trends of some typical intermediates has been discussed. Volatile organic acids (C2–C7) were chosen for a quantitative study of the intermediates because of their importance during coal bioconversion to methane. Fiber coating, extraction time, and solution acidity were optimized in the solid-phase micro-extraction procedure. The pressure was enhanced during the bioconversion process to investigate the influence of headspace pressure on analyte extraction. The detection limits of the method ranged from 0.0006 to 0.02 mmol/L for the volatile organic acids and the relative standard deviations were between 4.6% and 11.5%. The volatile organic acids (C2–C7) generated in the bioconversion process were 0.01–1.15 mmol/L with a recovery range from 80% to 105%. The developed method is useful for further in-depth research on the bioconversion of coal to methane. PMID:27695055

Highly sensitive and selective hyphenated technique (molecularly imprinted polymer solid-phase microextraction-molecularly imprinted polymer sensor) for ultra trace analysis of aspartic acid enantiomers.

PubMed

Prasad, Bhim Bali; Srivastava, Amrita; Tiwari, Mahavir Prasad

2013-03-29

The present work is related to combination of molecularly imprinted solid-phase microextraction and complementary molecularly imprinted polymer-sensor. The molecularly imprinted polymer grafted on titanium dioxide modified silica fiber was used for microextraction, while the same polymer immobilized on multiwalled carbon nanotubes/titanium dioxide modified pencil graphite electrode served as a detection tool. In both cases, the surface initiated polymerization was found to be advantageous to obtain a nanometer thin imprinted film. The modified silica fiber exhibited high adsorption capacity and enantioselective diffusion of aspartic acid isomers into respective molecular cavities. This combination enabled double preconcentrations of d- and l-aspartic acid that helped sensing both isomers in real samples, without any cross-selectivity and matrix complications. Taking into account 6×10(4)-fold dilution of serum and 2×10(3)-fold dilution of cerebrospinal fluid required by the proposed method, the limit of detection for l-aspartic acid is 0.031ngmL(-1). Also, taking into account 50-fold dilution required by the proposed method, the limit of detection for d-aspartic acid is 0.031ngmL(-1) in cerebrospinal fluid. Copyright © 2013 Elsevier B.V. All rights reserved.

Multivariate study of parameters in the determination of pesticide residues in apple by headspace solid phase microextraction coupled to gas chromatography-mass spectrometry using experimental factorial design.

PubMed

Abdulra'uf, Lukman Bola; Tan, Guan Huat

2013-12-15

Solid-phase microextraction (SPME) is a solvent-less sample preparation method which combines sample preparation, isolation, concentration and enrichment into one step. In this study, multivariate strategy was used to determine the significance of the factors affecting the solid phase microextraction of pesticide residues (fenobucarb, diazinon, chlorothalonil and chlorpyrifos) using a randomised factorial design. The interactions and effects of temperature, time and salt addition on the efficiency of the extraction of the pesticide residues were evaluated using 2(3) factorial designs. The analytes were extracted with 100 μm PDMS fibres according to the factorial design matrix and desorbed into a gas chromatography-mass spectrometry detector. The developed method was applied for the analysis of apple samples and the limits of detection were between 0.01 and 0.2 μg kg(-)(1), which were lower than the MRLs for apples. The relative standard deviations (RSD) were between 0.1% and 13.37% with average recovery of 80-105%. The linearity ranges from 0.5-50 μg kg(-)(1) with correlation coefficient greater than 0.99. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effects of push/pull perfusion and ultrasonication on the extraction efficiencies of phthalate esters in sports drink samples using on-line hollow-fiber liquid-phase microextraction.

PubMed

Chao, Yu-Ying; Lee, Chien-Hung; Chien, Tzu-Yang; Shih, Yu-Hsuan; Lu, Yin-An; Kuo, Ting-Hsuan; Huang, Yeou-Lih

2013-08-28

In previous studies, we developed a process, on-line ultrasound-assisted push/pull perfusion hollow-fiber liquid-phase microextraction (UA-PPP-HF-LPME), combining the techniques of push/pull perfusion (PPP) and ultrasonication with hollow-fiber liquid-phase microextraction (HF-LPME), to achieve rapid extraction of acidic phenols from water samples. In this present study, we further evaluated three more-advanced and novel effects of PPP and ultrasonication on the extraction efficiencies of neutral high-molecular-weight phthalate esters (HPAEs) in sports drinks. First, we found that inner-fiber fluid leakage occurs only in push-only perfusion-based and pull-only perfusion-based HF-LPME, but not in the PPP mode. Second, we identified a significant negative interaction between ultrasonication and temperature. Third, we found that the extraction time of the newly proposed system could be shortened by more than 93%. From an investigation of the factors affecting UA-PPP-HF-LPME, we established optimal extraction conditions and achieved acceptable on-line enrichment factors of 92-146 for HPAEs with a sampling time of just 2 min.

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.

Trace determination of five triazole fungicide residues in traditional Chinese medicine samples by dispersive solid-phase extraction combined with ultrasound-assisted dispersive liquid-liquid microextraction and UHPLC-MS/MS.

PubMed

Ma, Shuping; Yuan, Xucan; Zhao, Pengfei; Sun, Hong; Ye, Xiu; Liang, Ning; Zhao, Longshan

2017-08-01

A novel and reliable method for determination of five triazole fungicide residues (triadimenol, tebuconazole, diniconazole, flutriafol, and hexaconazol) in traditional Chinese medicine samples was developed using dispersive solid-phase extraction combined with ultrasound-assisted dispersive liquid-liquid microextraction before ultra-high performance liquid chromatography with tandem mass spectrometry. The clean up of the extract was conducted using dispersive solid-phase extraction by directly adding sorbents into the extraction solution, followed by shaking and centrifugation. After that, a mixture of 400 μL trichloromethane (extraction solvent) and 0.5 mL of the above supernatant was injected rapidly into water for the dispersive liquid-liquid microextraction procedure. The factors affecting the extraction efficiency were optimized. Under the optimum conditions, the calibration curves showed good linearity in the range of 2.0-400 (tebuconazole, diniconazole, and hexaconazole) and 4.0-800 ng/g (triadimenol and flutriafol) with the regression coefficients higher than 0.9958. The limit of detection and limit of quantification for the present method were 0.5-1.1 and 1.8-4.0 ng/g, respectively. The recoveries of the target analytes ranged from 80.2 to 103.2%. The proposed method has been successfully applied to the analysis of five triazole fungicides in traditional Chinese medicine samples, and satisfactory results were obtained. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determining octanol-water partition coefficients for extremely hydrophobic chemicals by combining "slow stirring" and solid-phase microextraction.

PubMed

Jonker, Michiel T O

2016-06-01

Octanol-water partition coefficients (KOW ) are widely used in fate and effects modeling of chemicals. Still, high-quality experimental KOW data are scarce, in particular for very hydrophobic chemicals. This hampers reliable assessments of several fate and effect parameters and the development and validation of new models. One reason for the limited availability of experimental values may relate to the challenging nature of KOW measurements. In the present study, KOW values for 13 polycyclic aromatic hydrocarbons were determined with the gold standard "slow-stirring" method (log KOW 4.6-7.2). These values were then used as reference data for the development of an alternative method for measuring KOW . This approach combined slow stirring and equilibrium sampling of the extremely low aqueous concentrations with polydimethylsiloxane-coated solid-phase microextraction fibers, applying experimentally determined fiber-water partition coefficients. It resulted in KOW values matching the slow-stirring data very well. Therefore, the method was subsequently applied to a series of 17 moderately to extremely hydrophobic petrochemical compounds. The obtained KOW values spanned almost 6 orders of magnitude, with the highest value measuring 10(10.6) . The present study demonstrates that the hydrophobicity domain within which experimental KOW measurements are possible can be extended with the help of solid-phase microextraction and that experimentally determined KOW values can exceed the proposed upper limit of 10(9) . Environ Toxicol Chem 2016;35:1371-1377. © 2015 SETAC. © 2015 SETAC.

Two-step liquid phase microextraction combined with capillary electrophoresis: a new approach to simultaneous determination of basic and zwitterionic compounds.

PubMed

Nojavan, Saeed; Moharami, Arezoo; Fakhari, Ali Reza

2012-08-01

In this work, two-step hollow fiber-based liquid-phase microextraction procedure was evaluated for extraction of the zwitterionic cetirizine (CTZ) and basic hydroxyzine (HZ) in human plasma. In the first step of extraction, the pH of sample was adjusted at 5.0 in order to promote liquid-phase microextraction of the zwitterionic CTZ. In the second step, the pH of sample was increased up to 11.0 for extraction of basic HZ. In this procedure, the extraction times for the first and the second steps were 30 and 20 min, respectively. Owing to the high ratio between the volumes of donor phase and acceptor phase, CTZ and HZ were enriched by factors of 280 and 355, respectively. The linearity of the analytical method was investigated for both compounds in the range of 10-500 ng mL(-1) (R(2) > 0.999). Limit of quantification (S/N = 10) for CTZ and HZ was 10 ng mL(-1) , while the limit of detection was 3 ng mL(-1) for both compounds at a signal to noise ratio of 3:1. Intraday and interday relative standard deviations (RSDs, n = 6) were in the range of 6.5-16.2%. This procedure enabled CTZ and HZ to be analyzed simultaneously by capillary electrophoresis. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Green aspects, developments and perspectives of liquid phase microextraction techniques.

PubMed

Spietelun, Agata; Marcinkowski, Łukasz; de la Guardia, Miguel; Namieśnik, Jacek

2014-02-01

Determination of analytes at trace levels in complex samples (e.g. biological or contaminated water or soils) are often required for the environmental assessment and monitoring as well as for scientific research in the field of environmental pollution. A limited number of analytical techniques are sensitive enough for the direct determination of trace components in samples and, because of that, a preliminary step of the analyte isolation/enrichment prior to analysis is required in many cases. In this work the newest trends and innovations in liquid phase microextraction, like: single-drop microextraction (SDME), hollow fiber liquid-phase microextraction (HF-LPME), and dispersive liquid-liquid microextraction (DLLME) have been discussed, including their critical evaluation and possible application in analytical practice. The described modifications of extraction techniques deal with system miniaturization and/or automation, the use of ultrasound and physical agitation, and electrochemical methods. Particular attention was given to pro-ecological aspects therefore the possible use of novel, non-toxic extracting agents, inter alia, ionic liquids, coacervates, surfactant solutions and reverse micelles in the liquid phase microextraction techniques has been evaluated in depth. Also, new methodological solutions and the related instruments and devices for the efficient liquid phase micoextraction of analytes, which have found application at the stage of procedure prior to chromatographic determination, are presented. © 2013 Published by Elsevier B.V.

Hollow fibre-based liquid phase microextraction combined with high-performance liquid chromatography for the analysis of flavonoids in Echinophora platyloba DC. and Mentha piperita.

PubMed

Hadjmohammadi, Mohammadreza; Karimiyan, Hanieh; Sharifi, Vahid

2013-11-15

A simple, inexpensive and efficient three phase hollow fibre liquid phase microextraction (HF-LPME) technique combined with HPLC was used for the simultaneous determination of flavonoids in Echinophora platyloba DC. and Mentha piperita. Different factors affecting the HF-LPME procedure were investigated and optimised. The optimised extraction conditions were as follows: 1-octanol as an organic solvent, pHdonor=2, pHacceptor=9.75, stirring rate of 1000rpm, extraction time of 80min, without addition of salt. Under these conditions, the enrichment factors ranged between 146 and 311. The values of intra and inter-day relative standard deviations (RSD) were in the range of 3.18-6.00% and 7.25-11.00%, respectively. The limits of detection (LODs) ranged between 0.5 and 7.0ngmL(-1). Among the investigated flavonoids quercetin was found in E. platyloba DC. and luteolin was found in M. piperita. Concentration of quercetin and luteolin was 0.015 and 0.025mgg(-1) respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

Solid phase microextraction of diclofenac using molecularly imprinted polymer sorbent in hollow fiber combined with fiber optic-linear array spectrophotometry.

PubMed

Pebdani, Arezou Amiri; Shabani, Ali Mohammad Haji; Dadfarnia, Shayessteh; Khodadoust, Saeid

2015-08-05

A simple solid phase microextraction method based on molecularly imprinted polymer sorbent in the hollow fiber (MIP-HF-SPME) combined with fiber optic-linear array spectrophotometer has been applied for the extraction and determination of diclofenac in environmental and biological samples. The effects of different parameters such as pH, times of extraction, type and volume of the organic solvent, stirring rate and donor phase volume on the extraction efficiency of the diclofenac were investigated and optimized. Under the optimal conditions, the calibration graph was linear (r(2)=0.998) in the range of 3.0-85.0 μg L(-1) with a detection limit of 0.7 μg L(-1) for preconcentration of 25.0 mL of the sample and the relative standard deviation (n=6) less than 5%. This method was applied successfully for the extraction and determination of diclofenac in different matrices (water, urine and plasma) and accuracy was examined through the recovery experiments. Copyright © 2015 Elsevier B.V. All rights reserved.

Optimisation of ultrasound-assisted reverse micelles dispersive liquid-liquid micro-extraction by Box-Behnken design for determination of acetoin in butter followed by high performance liquid chromatography.

PubMed

Roosta, Mostafa; Ghaedi, Mehrorang; Daneshfar, Ali

2014-10-15

A novel approach, ultrasound-assisted reverse micelles dispersive liquid-liquid microextraction (USA-RM-DLLME) followed by high performance liquid chromatography (HPLC) was developed for selective determination of acetoin in butter. The melted butter sample was diluted and homogenised by n-hexane and Triton X-100, respectively. Subsequently, 400μL of distilled water was added and the microextraction was accelerated by 4min sonication. After 8.5min of centrifugation, sedimented phase (surfactant-rich phase) was withdrawn by microsyringe and injected into the HPLC system for analysis. The influence of effective variables was optimised using Box-Behnken design (BBD) combined with desirability function (DF). Under optimised experimental conditions, the calibration graph was linear over the range of 0.6-200mgL(-1). The detection limit of method was 0.2mgL(-1) and coefficient of determination was 0.9992. The relative standard deviations (RSDs) were less than 5% (n=5) while the recoveries were in the range of 93.9-107.8%. Copyright © 2014. Published by Elsevier Ltd.

A liquid-phase microextraction method, combining a dual gauge microsyringe with a hollow fiber membrane, for the determination of organochlorine pesticides in aqueous solution by gas chromatography/ion trap mass spectrometry.

PubMed

Yan, Chih-Hao; Wu, Hui-Fen

2004-01-01

A liquid-phase microextraction (LPME) method has been demonstrated for the extraction and determination of organochlorine pesticides (OCPs) in aqueous solution. The method combines a dual gauge microsyringe with a hollow fiber membrane (LPME/DGM-HF) followed by detection by gas chromatography/ion trap mass spectrometry (GC/ITMS). The advantages include speed, low solvent and sample consumption, simplicity and ease of use. The extraction time, solvent selection, salt concentration and sample stirring rate have been investigated in order to optimize extraction efficiency. The viability is evaluated by measuring the linearity and detection limit of the five OCPs in aqueous solution. Detection linearity for the OCPs has been achieved over a range of concentrations between 1 and 500 microg/L (r2 > 0.930), with a detection limit of 0.1 microg/L for each OCP. Copyright 2004 John Wiley & Sons, Ltd.

Microextraction techniques for the determination of volatile and semivolatile organic compounds from plants: a review.

PubMed

Yang, Cui; Wang, Juan; Li, Donghao

2013-10-17

Vegetables and fruits are necessary for human health, and traditional Chinese medicine that uses plant materials can cure diseases. Thus, understanding the composition of plant matrix has gained increased attention in recent years. Since plant matrix is very complex, the extraction, separation and quantitation of these chemicals are challenging. In this review we focus on the microextraction techniques used in the determination of volatile and semivolatile organic compounds (such as esters, alcohols, aldehydes, hydrocarbons, ketones, terpenes, sesquiterpene, phenols, acids, plant secondary metabolites and pesticides) from plants (e.g., fruits, vegetables, medicinal plants, tree leaves, etc.). These microextraction techniques include: solid phase microextraction (SPME), stir-bar sorptive extraction (SBSE), single drop microextraction (SDME), hollow fiber liquid phase microextraction (HF-LPME), dispersive liquid liquid microextraction (DLLME), and gas purge microsyringe extraction (GP-MSE). We have taken into consideration papers published from 2008 to the end of January 2013, and provided critical and interpretative review on these techniques, and formulated future trends in microextraction for the determination of volatile and semivolatile compounds from plants. Copyright © 2013 Elsevier B.V. All rights reserved.

A dispersive liquid--liquid microextraction methodology for copper (II) in environmental samples prior to determination using microsample injection flame atomic absorption spectrometry.

PubMed

Alothman, Zeid A; Habila, Mohamed; Yilmaz, Erkan; Soylak, Mustafa

2013-01-01

A simple, environmentally friendly, and efficient dispersive liquid-liquid microextraction method combined with microsample injection flame atomic absorption spectrometry was developed for the separation and preconcentration of Cu(II). 2-(5-Bromo-2-pyridylazo)-5-(diethylamino)phenol (5-Br-PADAP) was used to form a hydrophobic complex of Cu(II) ions in the aqueous phase before extraction. To extract the Cu(II)-5-Br-PADAP complex from the aqueous phase to the organic phase, 2.0 mL of acetone as a disperser solvent and 200 microL of chloroform as an extraction solvent were used. The influences of important analytical parameters, such as the pH, types and volumes of the extraction and disperser solvents, amount of chelating agent, sample volume, and matrix effects, on the microextraction procedure were evaluated and optimized. Using the optimal conditions, the LOD, LOQ, preconcentration factor, and RSD were determined to be 1.4 microg/L, 4.7 microg/L, 120, and 6.5%, respectively. The accuracy of the proposed method was investigated using standard addition/recovery tests. The analysis of certified reference materials produced satisfactory analytical results. The developed method was applied for the determination of Cu in real samples.

Identification and Quantification of Pesticides in Environmental Waters With Solid Phase Microextraction and Analysis Using Field-Portable Gas Chromatography-Mass Spectrometry

DTIC Science & Technology

2004-06-10

Microextraction and Analysis using Field-Portable Gas Chromatography-Mass Spectrometry Name of Candidate: CPT Michael J. Nack...and Analysis using Field-Portable Gas Chromatography-Mass Spectrometry Beyond brief excerpts is with the permission of the copyright owner, and...Pesticides in Environmental Waters with Solid Phase Microextraction and Analysis using Field-Portable Gas Chromatography-Mass Spectrometry

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...

Growth dynamics of specific spoilage organisms and associated spoilage biomarkers in chicken breast stored aerobically

USDA-ARS?s Scientific Manuscript database

This study was performed to identify and quantify selected volatile spoilage biomarkers in a headspace over chicken breast using solid phase microextraction (SPME) combined with gas chromatography-mass spectrometry-flame ionization detectors (GC-MS/FID). The chicken breast samples were aerobically s...

Microextraction by Packed Sorbent (MEPS) and Solid-Phase Microextraction (SPME) as Sample Preparation Procedures for the Metabolomic Profiling of Urine

PubMed Central

Silva, Catarina; Cavaco, Carina; Perestrelo, Rosa; Pereira, Jorge; Câmara, José S.

2014-01-01

For a long time, sample preparation was unrecognized as a critical issue in the analytical methodology, thus limiting the performance that could be achieved. However, the improvement of microextraction techniques, particularly microextraction by packed sorbent (MEPS) and solid-phase microextraction (SPME), completely modified this scenario by introducing unprecedented control over this process. Urine is a biological fluid that is very interesting for metabolomics studies, allowing human health and disease characterization in a minimally invasive form. In this manuscript, we will critically review the most relevant and promising works in this field, highlighting how the metabolomic profiling of urine can be an extremely valuable tool for the early diagnosis of highly prevalent diseases, such as cardiovascular, oncologic and neurodegenerative ones. PMID:24958388

Solid-phase microextraction technology for in vitro and in vivo metabolite analysis

PubMed Central

Zhang, Qihui; Zhou, Liandi; Chen, Hua; Wang, Chong-Zhi; Xia, Zhining; Yuan, Chun-Su

2016-01-01

Analysis of endogenous metabolites in biological samples may lead to the identification of biomarkers in metabolomics studies. To achieve accurate sample analysis, a combined method of continuous quick sampling and extraction is required for online compound detection. Solid-phase microextraction (SPME) integrates sampling, extraction and concentration into a single solvent-free step for chemical analysis. SPME has a number of advantages, including simplicity, high sensitivity and a relatively non-invasive nature. In this article, we reviewed SPME technology in in vitro and in vivo analyses of metabolites after the ingestion of herbal medicines, foods and pharmaceutical agents. The metabolites of microorganisms in dietary supplements and in the gastrointestinal tract will also be examined. As a promising technology in biomedical and pharmaceutical research, SPME and its future applications will depend on advances in analytical technologies and material science. PMID:27695152

Fabrication of a novel nanocomposite based on sol-gel process for hollow fiber-solid phase microextraction of aflatoxins: B1 and B2, in cereals combined with high performane liquid chromatography-diode array detection.

PubMed

Es'haghi, Zarrin; Sorayaei, Hoda; Samadi, Fateme; Masrournia, Mahboubeh; Bakherad, Zohreh

2011-10-15

The new pre-concentration technique, hollow fiber-solid phase microextraction based on carbon nanotube reinforced sol-gel and liquid chromatography-photodiode array detection was applied to determination of aflatoxins B(1), B(2) (AFB(1), AFB(2)) in rice, peanut and wheat samples. This research provides an overview of trends related to synthesis of solid phase microextraction (SPME) sorbnents that improves the assay of aflatoxins as the semi-polar compounds in several real samples. It mainly includes summary and a list of the results for a simple carbon nanotube reinforced sol-gel in-fiber device. This device was used for extraction, pre-concentration and determination of aflatoxins B1, B2 in real samples. In this technique carbon nanotube reinforced sol was prepared by the sol-gel method via the reaction of phenyl trimethoxysilane (PTMS) with a basic catalyst (tris hydroxymethyl aminomethan). The influences of microextraction parameters such as pH, ageing time, carbon nanotube contents, desorption conditions, desorption solvent and agitation speed were investigated. Optimal HPLC conditions were: C(18) reversed phase column for separation, water-acetonitril-methanol (35:10:55) as the mobile phase and maximum wavelength for detection was 370 nm. The method was evaluated statistically and under optimized conditions, the detection limits for the analytes were 0.074 and 0.061 ng/mL for B1 and B2 respectively. Limit of quantification for B1 and B2 was 0.1 ng/mL too (n=7). The precisions were in the range of 2.829-2.976% (n=3), and linear ranges were within 0.1 and 400 ng/mL. The method was successfully applied to the analysis of cereals (peanut, wheat, rice) with the relative recoveries from 47.43% to 106.83%. Copyright © 2011 Elsevier B.V. All rights reserved.

In-line carbon nanofiber reinforced hollow fiber-mediated liquid phase microextraction using a 3D printed extraction platform as a front end to liquid chromatography for automatic sample preparation and analysis: A proof of concept study.

PubMed

Worawit, Chanatda; Cocovi-Solberg, David J; Varanusupakul, Pakorn; Miró, Manuel

2018-08-01

A novel concept for automation of nanostructured hollow-fiber supported microextraction, combining the principles of liquid-phase microextraction (LPME) and sorbent microextraction synergically, using mesofluidic platforms is proposed herein for the first time, and demonstrated with the determination of acidic drugs (namely, ketoprofen, ibuprofen, diclofenac and naproxen) in urine as a proof-of-concept applicability. Dispersed carbon nanofibers (CNF) are immobilized in the pores of a single-stranded polypropylene hollow fiber (CNF@HF) membrane, which is thereafter accommodated in a stereolithographic 3D-printed extraction chamber without glued components for ease of assembly. The analytical method involves continuous-flow extraction of the acidic drugs from a flowing stream donor (pH 1.7) into an alkaline stagnant acceptor (20 mmol L -1 NaOH) containing 10% MeOH (v/v) across a dihexyl ether impregnated CNF@HF membrane. The flow setup features entire automation of the microextraction process including regeneration of the organic film and on-line injection of the analyte-laden acceptor phase after downstream neutralization into a liquid chromatograph (LC) for reversed-phase core-shell column-based separation. Using a 12-cm long CNF@HF and a sample volume of 6.4 mL, linear dynamic ranges of ketoprofen, naproxen, diclofenac and ibuprofen, taken as models of non-steroidal anti-inflammatory drugs, spanned from ca. 5-15 µg L -1 to 500 µg L -1 with enhancement factors of 43-97 (against a direct injection of 10 µL standards into LC), and limits of detection from 1.6 to 4.3 µg L -1 . Relative recoveries in real urine samples ranged from 97% to 105%, thus demonstrating the reliability of the automatic CNF@HF-LPME method for in-line matrix clean-up and determination of drugs in urine at therapeutically relevant concentrations. Copyright © 2018 Elsevier B.V. All rights reserved.

Determination of fluoroquinolone antibiotics via ionic-liquid-based, salt-induced, dual microextraction in swine feed.

PubMed

Wang, Huili; Gao, Ming; Gao, Jiajia; Yu, Nana; Huang, Hong; Yu, Qing; Wang, Xuedong

2016-09-01

In conventional microextraction procedures, the disperser (organic solvent or ionic liquid) is left in the aqueous phase and discarded after finishing the microextraction process. Because the disperser is water-soluble, it results in low extraction recovery for polar compounds. In this investigation, an ionic-liquid-based microextraction (ILBME) was integrated with salting-out assisted liquid-liquid microextraction (SALLME) to build an ionic-liquid-based, salt-induced, dual microextraction (ILSDME) for isolation of five fluoroquinolone antibiotics (FQs) with high polarity (log P, -1.0 to 1.0). The proposed ILSDME method incorporates a dual microextraction by converting the disperser in the ILBME to the extractor in the SALLME. Optimization of key factors was conducted by integrating single-factor experiments and central composite design. The optimized experimental parameters were 80 μL [C8MIM][PF6] as extractor, 505 μL acetone as disperser, pH = 2.0, 4.1 min extraction time, and 4.2 g of Na2SO4. Under optimized conditions, high ERs (90.6-103.2 %) and low LODs (0.07-0.61 μg kg(-1)) were determined for five FQs in swine feed. Experimental precision based on RSDs was 1.4-5.2 % for intra-day and 2.4-6.9 % for inter-day analyses. The combination of ILBME with SALLME increased FQ recoveries by 15-20 % as compared with SALLME, demonstrating that the ILSDME method can enhance extraction efficiency for polar compounds compared to single-step microextraction. Therefore, the ILSDME method developed in this study has wide application for pretreatment of moderately to highly polar pollutants in complex matrices. Graphical Abstract A dual microextraction was developed by integrating ionic-liquid-based microextraction with salting-out assisted liquid-liquid microextraction for isolation of five fluoroquinolone antibiotics (FQs) with high polarity (log P = -1.0 to 1.0). The principle of dual microextraction is based on converting the remaining disperser from the first microextraction into an extractor in the second microextraction. Single-factor experiment and central composite design were applied for optimizing operational parameters using 3D response surfaces and contour lines. Under optimized conditions, the method provided high extraction recoveries and low LODs for five FQs in swine feed. The prominent advantage of the dual microextraction is rapid and highly efficient extraction of moderately to highly polar fluoroquinolones from complex matrices.

Simultaneous extraction and quantification of albendazole and triclabendazole using vortex-assisted hollow-fiber liquid-phase microextraction combined with high-performance liquid chromatography.

PubMed

Asadi, Mohammad; Haji Shabani, Ali Mohammad; Dadfarnia, Shayessteh

2016-06-01

A novel, simple, and rapid vortex-assisted hollow-fiber liquid-phase microextraction method was developed for the simultaneous extraction of albendazole and triclabendazole from various matrices before their determination by high-performance liquid chromatography with fluorescence detection. Several factors influencing the microextraction efficiency including sample pH, nature and volume of extraction solvent, ionic strength, vortex time, and sample volume were investigated and optimized. Under the optimal conditions, the limits of detection were 0.08 and 0.12 μg/L for albendazole and triclabendazole, respectively. The calibration curves were linear in the concentration ranges of 0.3-50.0 and 0.4-50.0 μg/L with the coefficients of determination of 0.9999 and 0.9995 for albendazole and triclabendazole, respectively. The interday and intraday relative standard deviations for albendazole and triclabendazole at three concentration levels (1.0, 10.0, and 30.0 μg/L) were in the range of 6.0-11.0 and 5.0-7.9%, respectively. The developed method was successfully applied to determine albendazole and triclabendazole in water, milk, honey, and urine samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of a New Microextraction Fiber Combined to On-Line Sample Stacking Capillary Electrophoresis UV Detection for Acidic Drugs Determination in Real Water Samples.

PubMed

Espina-Benitez, Maria; Araujo, Lilia; Prieto, Avismelsi; Navalón, Alberto; Vílchez, José Luis; Valera, Paola; Zambrano, Ana; Dugas, Vincent

2017-07-07

A new analytical method coupling a (off-line) solid-phase microextraction with an on-line capillary electrophoresis (CE) sample enrichment technique was developed for the analysis of ketoprofen, naproxen and clofibric acid from water samples, which are known as contaminants of emerging concern in aquatic environments. New solid-phase microextraction fibers based on physical coupling of chromatographic supports onto epoxy glue coated needle were studied for the off-line preconcentration of these micropollutants. Identification and quantification of such acidic drugs were done by capillary zone electrophoresis (CZE) using ultraviolet diode array detection (DAD). Further enhancement of concentration sensitivity detection was achieved by on-line CE "acetonitrile stacking" preconcentration technique. Among the eight chromatographic supports investigated, Porapak Q sorbent showed higher extraction and preconcentration capacities. The screening of parameters that influence the microextraction process was carried out using a two-level fractional factorial. Optimization of the most relevant parameters was then done through a surface response three-factor Box-Behnken design. The limits of detection and limits of quantification for the three drugs ranged between 0.96 and 1.27 µg∙L -1 and 2.91 and 3.86 µg∙L -1 , respectively. Recovery yields of approximately 95 to 104% were measured. The developed method is simple, precise, accurate, and allows quantification of residues of these micropollutants in Genil River water samples using inexpensive fibers.

Development of a New Microextraction Fiber Combined to On-Line Sample Stacking Capillary Electrophoresis UV Detection for Acidic Drugs Determination in Real Water Samples

PubMed Central

Araujo, Lilia; Prieto, Avismelsi; Navalón, Alberto; Vílchez, José Luis; Valera, Paola; Zambrano, Ana; Dugas, Vincent

2017-01-01

A new analytical method coupling a (off-line) solid-phase microextraction with an on-line capillary electrophoresis (CE) sample enrichment technique was developed for the analysis of ketoprofen, naproxen and clofibric acid from water samples, which are known as contaminants of emerging concern in aquatic environments. New solid-phase microextraction fibers based on physical coupling of chromatographic supports onto epoxy glue coated needle were studied for the off-line preconcentration of these micropollutants. Identification and quantification of such acidic drugs were done by capillary zone electrophoresis (CZE) using ultraviolet diode array detection (DAD). Further enhancement of concentration sensitivity detection was achieved by on-line CE “acetonitrile stacking” preconcentration technique. Among the eight chromatographic supports investigated, Porapak Q sorbent showed higher extraction and preconcentration capacities. The screening of parameters that influence the microextraction process was carried out using a two-level fractional factorial. Optimization of the most relevant parameters was then done through a surface response three-factor Box-Behnken design. The limits of detection and limits of quantification for the three drugs ranged between 0.96 and 1.27 µg∙L−1 and 2.91 and 3.86 µg∙L−1, respectively. Recovery yields of approximately 95 to 104% were measured. The developed method is simple, precise, accurate, and allows quantification of residues of these micropollutants in Genil River water samples using inexpensive fibers. PMID:28686186

Combination of solid phase extraction and dispersive liquid-liquid microextraction for separation/preconcentration of ultra trace amounts of uranium prior to its fiber optic-linear array spectrophotometry determination.

PubMed

Dadfarnia, Shayessteh; Shabani, Ali Mohammad Haji; Shakerian, Farid; Shiralian Esfahani, Golnaz

2013-12-15

A simple and sensitive method for the separation and preconcentration of the ultra trace amounts of uranium and its determination by spectrophotometry was developed. The method is based on the combination of solid phase extraction and dispersive liquid-liquid microextraction. Thus, by passing the sample through the basic alumina column, the uranyl ion and some cations are separated from the sample matrix. The retained uranyl ion along with the cations are eluted with 5 mL of nitric acid (2 mol L(-1)) and after neutralization of the eluent, the extracted uranyl ion is converted to its anionic benzoate complex and is separated from other cations by extraction of its ion pair with malachite green into small volume of chloroform using dispersive liquid-liquid microextraction. The amount of uranium is then determined by the absorption measurement of the extracted ion pair at 621 nm using flow injection spectrophotometry. Under the optimum conditions, with 500 mL of the sample, a preconcentration factor of 1980, a detection limit of 40 ng L(-1), and a relative standard deviation of 4.1% (n=6) at 400 ng L(-1) were obtained. The method was successfully applied to the determination of uranium in mineral water, river water, well water, spring water and sea water samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Sensitive determination of three aconitum alkaloids and their metabolites in human plasma by matrix solid-phase dispersion with vortex-assisted dispersive liquid-liquid microextraction and HPLC with diode array detection.

PubMed

Wang, Xiaozhong; Li, Xuwen; Li, Lanjie; Li, Min; Liu, Ying; Wu, Qian; Li, Peng; Jin, Yongri

2016-05-01

A simple and sensitive method for determination of three aconitum alkaloids and their metabolites in human plasma was developed using matrix solid-phase dispersion combined with vortex-assisted dispersive liquid-liquid microextraction and high-performance liquid chromatography with diode array detection. The plasma sample was directly purified by matrix solid-phase dispersion and the eluate obtained was concentrated and further clarified by vortex-assisted dispersive liquid-liquid microextraction. Some important parameters affecting the extraction efficiency, such as type and amount of dispersing sorbent, type and volume of elution solvent, type and volume of extraction solvent, salt concentration as well as sample solution pH, were investigated in detail. Under optimal conditions, the proposed method has good repeatability and reproducibility with intraday and interday relative standard deviations lower than 5.44 and 5.75%, respectively. The recoveries of the aconitum alkaloids ranged from 73.81 to 101.82%, and the detection limits were achieved within the range of 1.6-2.1 ng/mL. The proposed method offered the advantages of good applicability, sensitivity, simplicity, and feasibility, which makes it suitable for the determination of trace amounts of aconitum alkaloids in human plasma samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabrication of polyaniline-coated halloysite nanotubes by in situ chemical polymerization as a solid-phase microextraction coating for the analysis of volatile organic compounds in aqueous solutions.

PubMed

Abolghasemi, Mir Mahdi; Arsalani, Naser; Yousefi, Vahid; Arsalani, Mahmood; Piryaei, Marzieh

2016-03-01

We have synthesized an organic-inorganic polyaniline-halloysite nanotube composite by an in situ polymerization method. This nanocomposite is immobilized on a stainless-steel wire and can be used as a fiber coating for solid-phase microextraction. It was found that our new solid-phase microextraction fiber is an excellent adsorbent for the extraction of some volatile organic compounds in aqueous samples in combination with gas chromatography and mass spectrometry. The coating can be prepared easily, is mechanically stable, and exhibits relatively high thermal stability. It is capable of extracting phenolic compounds from water samples. Following thermal desorption, the phenols were quantified by gas chromatography with mass spectrometry. The effects of extraction temperature, extraction time, sample ionic strength, stirring rate, pH, desorption temperature and desorption time were studied. Under optimal conditions, the repeatability for one fiber (n = 5), expressed as the relative standard deviation, is between 6.2 and 9.1%. The detection limits range from 0.005 to 4 ng/mL. The method offers the advantage of being simple to use, with a shorter analysis time, lower cost of equipment and higher thermal stability of the fiber in comparison to conventional methods of analysis. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solid-phase extraction in combination with dispersive liquid-liquid microextraction and ultra-high performance liquid chromatography-tandem mass spectrometry analysis: the ultra-trace determination of 10 antibiotics in water samples.

PubMed

Liang, Ning; Huang, Peiting; Hou, Xiaohong; Li, Zhen; Tao, Lei; Zhao, Longshan

2016-02-01

A novel method, solid-phase extraction combined with dispersive liquid-liquid microextraction (SPE-DLLME), was developed for ultra-preconcentration of 10 antibiotics in different environmental water samples prior to ultra-high performance liquid chromatography-tandem mass spectrometry detection. The optimized results were obtained as follows: after being adjusted to pH 4.0, the water sample was firstly passed through PEP-2 column at 10 mL min(-1), and then methanol was used to elute the target analytes for the following steps. Dichloromethane was selected as extraction solvent, and methanol/acetonitrile (1:1, v/v) as dispersive solvent. Under optimal conditions, the calibration curves were linear in the range of 1-1000 ng mL(-1) (sulfamethoxazole, cefuroxime axetil), 5-1000 ng mL(-1) (tinidazole), 10-1000 ng mL(-1) (chloramphenicol), 2-1000 ng mL(-1) (levofloxacin oxytetracycline, doxycycline, tetracycline, and ciprofloxacin) and 1-400 ng mL(-1) (sulfadiazine) with a good precision. The LOD and LOQ of the method were at very low levels, below 1.67 and 5.57 ng mL(-1), respectively. The relative recoveries of the target analytes were in the range from 64.16% to 99.80% with relative standard deviations between 0.7 and 8.4%. The matrix effect of this method showed a great decrease compared with solid-phase extraction and a significant value of enrichment factor (EF) compared with dispersive liquid-liquid microextraction. The developed method was successfully applied to the extraction and analysis of antibiotics in different water samples with satisfactory results.

Emerging Environmental Contaminants and Soled Phase Microextraction: Janusz Pawliszyn's Legacy in the Environmental Arena

EPA Science Inventory

Solid phase microextraction (SPME) has revolutionized the way samples are extracted, enabling rapid, automated, and solventless extraction of many different sample types, including air, water, soil, and biological samples. As such, SPME is widely used for environmental, food, fo...

Optimization of headspace solid phase micro-extraction of volatile compounds from papaya fruit assisted by GC-olfactometry.

PubMed

da Rocha, Renier Felinto Julião; da Silva Araújo, Ídila Maria; de Freitas, Sílvia Maria; Dos Santos Garruti, Deborah

2017-11-01

Optimization of the extraction conditions to investigate the volatile composition of papaya fruit involving headspace solid phase micro-extraction was carried out using multivariate strategies such as factorial design and response surface methodology. The performance of different combinations of time for reaching the equilibrium in the headspace and time for maximum extraction of volatiles was evaluated by GC-olfactometry of the extract (intensity of papaya characteristic aroma), number of peaks and total area in the chromatogram. Thirty-two compounds were identified by GC-MS under the optimized extraction conditions, the majority of which were aldehydes, both in number of compounds and area. Major compounds were δ-octalactone, β-citral, benzaldehyde, heptanal, benzyl isothiocyanate, isoamyl acetate, γ-octalactone, (E)-linalool oxide and benzyl alcohol. Seven aldehydes and two other compounds are reported for the first time in papaya's volatile profile.

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.

Determination of volatile monophenols in beer using acetylation and headspace solid-phase microextraction in combination with gas chromatography and mass spectrometry.

PubMed

Sterckx, Femke L; Saison, Daan; Delvaux, Freddy R

2010-08-31

Monophenols are widely spread compounds contributing to the flavour of many foods and beverages. They are most likely present in beer, but so far, little is known about their influence on beer flavour. To quantify these monophenols in beer, we optimised a headspace solid-phase microextraction method coupled to gas chromatography-mass spectrometry. To improve their isolation from the beer matrix and their chromatographic properties, the monophenols were acetylated using acetic anhydride and KHCO(3) as derivatising agent and base catalyst, respectively. Derivatisation conditions were optimised with attention for the pH of the reaction medium. Additionally, different parameters affecting extraction efficiency were optimised, including fibre coating, extraction time and temperature and salt addition. Afterwards, we calibrated and validated the method successfully and applied it for the analysis of monophenols in beer samples. 2010 Elsevier B.V. All rights reserved.

Silk fiber for in-tube solid-phase microextraction to detect aldehydes by chemical derivatization.

PubMed

Wang, Xiuqin; Pan, Lei; Feng, Juanjuan; Tian, Yu; Luo, Chuannan; Sun, Min

2017-11-03

Aldehydes are the potentially damaging pollutants in the environment, but it is difficult to be determined due to the low concentration level. Therefore, to accurate analysis of aldehydes, it is important for efficient sample preparation with selective enrichment and rapid separation. Environmentally friendly silk fiber as adsorbent material was directly applied to develop in-tube solid-phase microextraction for analyzing aqueous samples combined with high performance liquid chromatography. 2,4-Dinitrophenylhydrazine as a derivative reagent was used for chemical derivatization of aldehydes before extraction. Under optimum conditions, an online analysis method was built with the limits of detection in the range of 0.005-0.01μgL -1 and the linearity in the range of 0.03-10μgL -1 . Three aldehydes were determined in two real samples, and the relative recoveries were in the range of 95-102%. Copyright © 2017 Elsevier B.V. All rights reserved.

Deep eutectic liquid organic salt as a new solvent for liquid-phase microextraction and its application in ligandless extraction and preconcentraion of lead and cadmium in edible oils.

PubMed

Karimi, Mehdi; Dadfarnia, Shayessteh; Shabani, Ali Mohammad Haji; Tamaddon, Fatemeh; Azadi, Davood

2015-11-01

Deep eutectic liquid organic salt was used as the solvent and a liquid phase microextraction (DES-LPME) combined with electrothermal atomic absorption spectrometry (ETAAS) was developed for separation, preconcentration and determination of lead and cadmium in edible oils. A 4:1 mixture of deep eutectic solvent and 2% nitric acid (200 µL) was added to an oil sample. The mixture was vortexed and transferred into a water bath at 50 °C and stirred for 5 minutes. After the extraction was completed, the phases were separated by centrifugation, and the enriched analytes in the deep eutectic solvent phase were determined by ETAAS. Under optimized extraction conditions and for an oil sample of 28 g, enhancement factors of 198 and 195 and limits of detection (defined as 3 Sb/m) of 8 and 0. 2 ng kg(-1) were achieved for lead and cadmium respectively. The method was successfully applied to the determination of lead and cadmium in various edible oils. Copyright © 2015. Published by Elsevier B.V.

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%.

SOLID PHASE MICROEXTRACTION FOR TRACE LEVEL ANALYSIS OF DISINFECTION BY-PRODUCTS

EPA Science Inventory

This presentation focuses on the development of a solid-phase microextraction (SPME)-gas chromatography (GC)/ion trap mass spectrometry (MS) method for the analysis of semivolatile disinfection by-products (DBPs) in drinking water in the low ug/L range. These DBPs were selected ...

Discovering Volatile Chemicals from Window Weatherstripping through Solid-Phase Microextraction/Gas Chromatography-Mass Spectrometry

ERIC Educational Resources Information Center

Rosu, Cornelia; Cueto, Rafael; Veillion, Lucas; David, Connie; Laine, Roger A.; Russo, Paul S.

2017-01-01

Volatile compounds from polymeric materials such as weatherstripping were identified by solid-phase microextraction (SPME), a solvent-free analytical method, coupled to gas chromatography-mass spectrometry (GC-MS). These compounds, originating from additives and fillers used in weatherstripping processing, were mostly polycyclic aromatic…

Headspace analysis of polar organic compounds in biological matrixes using solid phase microextraction (SPME)

USDA-ARS?s Scientific Manuscript database

Analysis of biological fluids and waste material is difficult and tedious given the sample matrix. A rapid automated method for the determination of volatile fatty acids and phenolic and indole compounds was developed using a multipurpose sampler (MPS) with solid phase microextraction (SPME) and GC-...

Simultaneous determination of three purines in Alysicarpus vaginalis (L.) DC. by hollow fiber-based liquid-phase microextraction combined with high-performance liquid chromatography.

PubMed

Liu, Hongjiao; Lei, Ming; Liang, Xiao; Jiang, Zhen; Guo, Xingjie

2014-02-01

In this paper, a three-phase hollow fiber liquid-phase microextraction (HF-LPME) method combined with high-performance liquid chromatography (HPLC) was developed for the determination of hypoxanthine (HX), xanthine (Xan) and adenine (A) and then for the first time successfully applied to the analysis of HX, Xan and A in Alysicarpus vaginalis (L.) DC. medicinal materials. Different factors affecting the HF-LPME procedure were investigated and optimized. Under optimal extraction conditions (1-octanol as organic solvent, pH of the donor and acceptor phase 10.0 and 3.5, respectively, extraction time 40 min, stirring rate 800 rpm and salt addition 10%, w/v), HX, Xan and A could be determined within the test ranges with a good correlation coefficient (r(2) > 0.9992). The limit of detection for HX, Xan and A was 153, 173 and 97 ng/mL, respectively, and the intra- and inter-day relative standard deviations were no more than 9.8%. The content of HX, Xan and A in Alysicarpus vaginalis (L.) DC. medicinal materials was 120.40, 18.37 and 62.75 µg/g, respectively. This procedure afforded a convenient, sensitive, accurate and inexpensive method with a high extraction efficiency for determination of HX, Xan and A. Copyright © 2013 John Wiley & Sons, Ltd.

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.

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...

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.

A review on development of solid phase microextraction fibers by sol-gel methods and their applications.

PubMed

Kumar, Ashwini; Gaurav; Malik, Ashok Kumar; Tewary, Dhananjay Kumar; Singh, Baldev

2008-03-03

Solid phase microextraction (SPME) is an innovative, solvent free technology that is fast, economical and versatile. SPME is a fiber coated with a liquid (polymer), a solid (sorbent) or a combination of both. The fiber coating takes up the compounds from the sample by absorption in the case of liquid coatings or adsorption in the case of solid coatings. The SPME fiber is then transferred with the help of a syringe like device into the analytical instrument for desorption and analysis of the target analytes. The sol-gel process provides a versatile method to prepare size, shape and charge selective materials of high purity and homogeneity by means of preparation techniques different from the traditional ones, for the chemical analysis. This review is on the current state of the art and future trends in the developments of solid phase microextraction (SPME) fibers using sol-gel method. To achieve more selective determination of different compound classes, the variety of different coating material for SPME fibers has increased. Further developments in SPME as a highly efficient extraction technique, will greatly depend on new breakthroughs in the area of new coating material developments for the SPME fibers. In sol-gel approach, appropriate sol-gel precursors and other building blocks can be selected to create a stationary phase with desired structural and surface properties. This approach is efficient in integrating the advantageous properties of organic and inorganic material systems and thereby increasing and improving the extraction selectivity of the produced amalgam organic-inorganic stationary phases. This review is mainly focused on recent advanced developments in the design, synthesis, characterisation, properties and application of sol-gel in preparation of coatings for the SPME fibers.

Solid Phase Microextraction and Related Techniques for Drugs in Biological Samples

PubMed Central

Moein, Mohammad Mahdi; Said, Rana; Bassyouni, Fatma

2014-01-01

In drug discovery and development, the quantification of drugs in biological samples is an important task for the determination of the physiological performance of the investigated drugs. After sampling, the next step in the analytical process is sample preparation. Because of the low concentration levels of drug in plasma and the variety of the metabolites, the selected extraction technique should be virtually exhaustive. Recent developments of sample handling techniques are directed, from one side, toward automatization and online coupling of sample preparation units. The primary objective of this review is to present the recent developments in microextraction sample preparation methods for analysis of drugs in biological fluids. Microextraction techniques allow for less consumption of solvent, reagents, and packing materials, and small sample volumes can be used. In this review the use of solid phase microextraction (SPME), microextraction in packed sorbent (MEPS), and stir-bar sorbtive extraction (SBSE) in drug analysis will be discussed. In addition, the use of new sorbents such as monoliths and molecularly imprinted polymers will be presented. PMID:24688797

Porous organic polymers with different pore structures for sensitive solid-phase microextraction of environmental organic pollutants.

PubMed

Huang, Zhoubing; Liu, Shuqin; Xu, Jianqiao; Yin, Li; Zheng, Juan; Zhou, Ningbo; Ouyang, Gangfeng

2017-10-09

Adsorption capacity is the major sensitivity-limited factor in solid-phase microextraction. Due to its light-weight properties, large specific surface area and high porosity, especially tunable pore structures, the utilization of porous organic polymers as solid-phase microextraction adsorbents has attracting researchers' attentions. However, these works mostly concentrated on the utilization of specific porous organic polymers for preparing high-performance solid-phase microextraction coatings. The relationship between pore structures and adsorption performance of the porous organic polymers still remain unclear. Herein, three porous organic polymers with similar properties but different pore distributions were prepared by condensation polymerization reaction of phloroglucinol and terephthalaldehyde, which were fabricated as solid-phase microextraction coatings subsequently. The adsorption capacity of the porous organic polymers-coated fibers were evaluated by using benzene and its derivatives (i.e.,benzene, toluene, ethylbenzene and m-xylene) and polycyclic aromatic hydrocarbons as the target analytes. The results showed that the different adsorption performance of these porous organic polymers was mainly caused by their different pore volumes instead of their surface areas or pore sizes. Finally, the proposed method by using the mesoporous organic polymer coating was successfully applied to the determination of benzene and its derivatives in environmental water samples. As for analytical performance, high pre-concentration factors (74-2984), satisfactory relative recoveries (94.5 ± 18.5-116.9 ± 12.5%), intraday precision (2.44-5.34%), inter-day precision (4.62-7.02%), low limit of detections (LODs, 0.10-0.29 ng L -1 ) and limit of quantifications (LOQs, 0.33-0.96 ng L -1 ) were achieved under the optimal conditions. This study provides an important idea in the rational design of porous organic polymers for solid-phase microextraction or other adsorption applications. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

Preparation and application of carbon nanotubes/poly(o-toluidine) composite fibers for the headspace solid-phase microextraction of benzene, toluene, ethylbenzene, and xylenes.

PubMed

Behzadi, Mansoureh; Noroozian, Ebrahim; Mirzaei, Mohammad

2013-11-01

A novel nanocomposite coating of poly(o-toluidine) and oxidized multiwalled CNTs (MWCNTs, where CNTs is carbon nanotubes) was electrochemically prepared on a stainless-steel wire. The applicability of the fiber was assessed for the headspace solid-phase microextraction of benzene, toluene, ethylbenzene, and xylenes in aqueous samples followed by GC with flame ionization detection. In order to obtain an adherent and stable composite coating, several experimental parameters related to the coating process, such as polymerization potential and time, and the concentration of o-toluidine and oxidized MWCNTs were optimized. The combination of MWCNTs and polymer in a nanocomposite form presents desirable opportunities to produce materials for new applications. The effects of various parameters on the efficiency of the headspace solid-phase microextraction process, such as desorption temperature and time, extraction temperature and time, and ionic strength were also investigated. At the optimum conditions, LODs were 0.03-0.06 μg/L. The method showed linearity in the range of 0.5-300 μg/L with coefficients of determination >0.99. The intraday and interday RSDs obtained at a 5 μg/L concentration level (n = 5) using a single fiber were 1.2-5.2 and 3.2-7.5%, respectively. The fiber-to-fiber RSD (%; n = 3) at 5 μg/L was 6.1-9.2%. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

Development of Hollow-Fiber Liquid-Phase Microextraction Method for Determination of Urinary trans,trans-Muconic Acid as a Biomarker of Benzene Exposure

PubMed Central

Ghamari, Farhad; Bahrami, Abdulrahman; Yamini, Yadollah; Shahna, Farshid Ghorbani; Moghimbeigi, Abbas

2016-01-01

For the first time, hollow-fiber liquid-phase microextraction combined with high-performance liquid chromatography–ultraviolet was used to extract trans,trans-muconic acid, in urine samples of workers who had been exposed to benzene. The parameters affecting the metabolite extraction were optimized as follows: the volume of sample solution was 11 mL with pH 2, liquid membrane containing dihexyl ether as the supporter, 15% (w/v) of trioctylphosphine oxide as the carrier, the time of extraction was 120 minutes, and stirring rate was 500 rpm. Organic phase impregnated in the pores of a hollow fiber was extracted into 24 µL solution of 0.05 mol L−1 Na2CO3 located inside the lumen of the fiber. Under optimized conditions, a high enrichment factor of 153–182 folds, relative recovery of 83%–92%, and detection limit of 0.001 µg mL−1 were obtained. The method was successfully applied to the analysis of ttMA in real urine samples. PMID:27660405

Automated dynamic liquid-liquid-liquid microextraction followed by high-performance liquid chromatography-ultraviolet detection for the determination of phenoxy acid herbicides in environmental waters.

PubMed

Wu, Jingming; Ee, Kim Huey; Lee, Hian Kee

2005-08-05

Automated dynamic liquid-liquid-liquid microextraction (D-LLLME) controlled by a programmable syringe pump and combined with HPLC-UV was investigated for the extraction and determination of 5 phenoxy acid herbicides in aqueous samples. In the extraction procedure, the acceptor phase was repeatedly withdrawn into and discharged from the hollow fiber by the syringe pump. The repetitive movement of acceptor phase into and out of the hollow fiber channel facilitated the transfer of analytes into donor phase, from the organic phase held in the pore of the fiber. Parameters such as the organic solvent, concentrations of the donor and acceptor phases, plunger movement pattern, speed of agitation and ionic strength of donor phase were evaluated. Good linearity of analytes was achieved in the range of 0.5-500 ng/ml with coefficients of determination, r2 > 0.9994. Good repeatabilities of extraction performance were obtained with relative standard deviations lower than 7.5%. The method provided up-to 490-fold enrichment within 13 min. In addition, the limits of detection (LODs) ranged from 0.1 to 0.4 ng/mL (S/N = 3). D-LLLME was successfully applied for the analysis of phenoxy acid herbicides from real environmental water samples.

Preparation of porous aromatic framework/ionic liquid hybrid composite coated solid-phase microextraction fibers and their application in the determination of organochlorine pesticides combined with GC-ECD detection.

PubMed

Wu, Mingxue; Chen, Gang; Liu, Ping; Zhou, Weihong; Jia, Qiong

2016-01-07

A novel hybrid material incorporating porous aromatic frameworks and an ionic liquid, 1-(triethoxy silyl)propyl-3-aminopropyl imidazole hexafluorophosphate, was prepared as solid-phase microextraction coating and employed for the extraction of organochlorine pesticides. Combining the advantages of porous aromatic frameworks and an ionic liquid, the fiber exhibited a high adsorption capacity for organochlorine pesticides. Under optimized experimental conditions, enhancement factors of 247-1696 were obtained with good linearity in the range of 1-500 μg L(-1). The detection limits and quantification limits were determined to be in the range of 0.11-0.29 μg L(-1) and 0.35-0.93 μg L(-1). The relative standard deviations for six replicates of organochlorine pesticides were in the range of 4.4%-7.2% and 5.7%-10.1% for one fiber and fiber-to-fiber, respectively. By coupling with a gas chromatography-electron capture detector, the novel fiber was successfully used for the determination of organochlorine pesticides in juice and milk samples with recoveries of 76.1%-121.3%.

HIGH LEVELS OF MONOAROMATIC COMPOUNDS LIMIT THE USE OF SOLID-PHASE MICROEXTRACTION OF METHYL TERTIARY BUTYL ETHER AND TERTIARY BUTYL ALCOHOL

EPA Science Inventory

Recently, two papers reported the use of solid-phase microextraction (SPME) with polydimethylsiloxane(PDMS)/Carboxen fibers to determine trace levels of methyl tertiary butyl ether (MTBE) and tertiary butyl alcohol (tBA) in water. Attempts were made to apply this technique to th...

Freeze-thaw method improves the detection of volatile compounds in insects using Headspace Solid-Phase Microextraction (HS-SPME)

USDA-ARS?s Scientific Manuscript database

Headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography–mass spectrometry (GC-MS) is commonly used in analyzing insect volatiles. In order to improve the detection of volatiles in insects, a freeze-thaw method was applied to insect samples before the HS-SPME-GC-MS analysis. ...

Applicability of solid-phase microextraction combined with gas chromatography atomic emission detection (GC-MIP AED) for the determination of butyltin compounds in sediment samples.

PubMed

Carpinteiro, J; Rodríguez, I; Cela, R

2004-11-01

The performance of solid-phase microextraction (SPME) applied to the determination of butyltin compounds in sediment samples is systematically evaluated. Matrix effects and influence of blank signals on the detection limits of the method are studied in detail. The interval of linear response is also evaluated in order to assess the applicability of the method to sediments polluted with butyltin compounds over a large range of concentrations. Advantages and drawbacks of including an SPME step, instead of the classic liquid-liquid extraction of the derivatized analytes, in the determination of butyltin compounds in sediment samples are considered in terms of achieved detection limits and experimental effort. Analytes were extracted from the samples by sonication using glacial acetic acid. An aliquot of the centrifuged extract was placed on a vial where compounds were ethylated and concentrated on a PDMS fiber using the headspace mode. Determinations were carried out using GC-MIP AED.

Application of solid-phase microextraction in the investigation of protein binding of pharmaceuticals.

PubMed

Theodoridis, Georgios

2006-01-18

Protein-drug interactions of seven common pharmaceuticals were studied using solid-phase microextraction (SPME). SPME can be used in such investigations on the condition that no analyte depletion occurs. In multi-compartment systems (e.g. a proteinaceous matrix) only the free portion of the analyte is able to partition into the SPME fiber. In addition if no sample depletion occurs, the bound drug-free drug equilibria are not disturbed. In the present study seven pharmaceuticals (quinine, quinidine, naproxen, ciprofloxacin, haloperidol, paclitaxel and nortriptyline) were assayed by SPME. For quantitative purposes SPME was validated first in the absence of proteins. Calibration curves were constructed for each drug by HPLC-fluorescence and HPLC-UV analysis. SPME was combined to HPLC off-line, desorption occurring in HPLC inserts filled with 200 microL methanol. Binding of each drug to human serum albumin was studied independently. Experimental results were in agreement with literature data and ultrafiltration experiments, indicating the feasibility of the method for such bioanalytical purposes.

Capillary liquid chromatographic analysis of fat-soluble vitamins and beta-carotene in combination with in-tube solid-phase microextraction.

PubMed

Xu, Hui; Jia, Li

2009-01-01

A capillary liquid chromatography (CLC) system with UV/vis detection was coupled with an in-tube solid-phase microextraction (SPME) device for the analysis of fat-soluble vitamins and beta-carotene. A monolithic silica-ODS column was used as the extraction medium. An optical-fiber flow cell with a long light path in the UV/vis detector was utilized to further enhance the detection sensitivity. In the in-tube SPME/CLC system, the pre-condition of the extraction column and the effect of the injection volume were investigated. The detection limits (LOD) for the fat-soluble vitamins and beta-carotene were in the range from 1.9 to 173 ng/mL based on the signal-to-noise ratio of 3 (S/N=3). The relative standard deviations of migration time and peak area for each analyte were less than 5.0%. The method was applied to the analysis of fat-soluble vitamins and beta-carotene contents in corns.

Quantitative Determination of Caffeine in Beverages Using a Combined SPME-GC/MS Method

NASA Astrophysics Data System (ADS)

Pawliszyn, Janusz; Yang, Min J.; Orton, Maureen L.

1997-09-01

Solid-phase microextraction (SPME) combined with gas chromatography/mass spectrometry (GC/MS) has been applied to the analysis of various caffeinated beverages. Unlike the current methods, this technique is solvent free and requires no pH adjustments. The simplicity of the SPME-GC/MS method lends itself to a good undergraduate laboratory practice. This publication describes the analytical conditions and presents the data for determination of caffeine in coffee, tea, and coke. Quantitation by isotopic dilution is also illustrated.

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, ...

Rapid Analysis of Chemical Warfare Agents and Their Hydrolysis Products by Desorption Electrospray Ionization Mass Spectrometry (DESI-MS)

DTIC Science & Technology

2009-10-01

of chemical warfare agents in natural water samples by solid-phase microextraction. Anal. Chem., 69, 1866-72. [36] Sng , M.T. and Ng ,W.F. (1999). In...liquid phase microextraction of alkylphosphonic acids from water. J. Chromatogr. A., 1141, 151-157. [43] Lee, H.S.N., Sng , M.T., Basheer, C., and Lee

Headspace and direct immersion solid phase microextraction procedures for selenite determination in urine, saliva and milk by gas chromatography mass spectrometry.

PubMed

Kapsimali, D C; Zachariadis, G A

2009-10-01

Two solid phase microextraction modes were investigated and compared for their performance on the determination of selenites in various biological liquids like human urine and saliva and various types of milk. Using sodium tetraethylborate (NaBEt(4)) as ethylating reagent, selenites are converted in situ to volatile diethylselenides (DESe) in aqueous medium. The derivative is collected in situ by solid phase microextraction (SPME) using a silica fiber coated with poly(dimethylsiloxane) (PDMS) either from the headspace (HS-SPME) or directly from the liquid phase (LP-SPME) and finally determined by capillary GC/MS. Under optimum conditions of SPME, the GC separation was also optimized. Between the two examined microextraction techniques, direct immersion of the PDMS fiber in the liquid phase was proved less satisfactory. In contrast, the headspace procedure appears to be more efficient. The quantification of selenites was achieved in SIM mode with good analytical performance. A non-fat milk powder certified reference material was analyzed to evaluate the accuracy of the method. The overall precision of the method was ranged between 6.2% and 9.7%. Detection limits achieved were 0.05microgL(-1) for human urine, 0.08microgL(-1) for saliva and 0.03-0.06microgL(-1) in various milk matrices.

Rapid determination of some beta-blockers in complicated matrices by tandem dispersive liquid-liquid microextraction followed by high performance liquid chromatography.

PubMed

Hemmati, Maryam; Asghari, Alireza; Bazregar, Mohammad; Rajabi, Maryam

2016-11-01

In this research work, an efficient tandem dispersive liquid-liquid microextraction (TDLLME) procedure coupled with high performance liquid chromatography-ultraviolet detection (HPLC-UV) was successfully applied for the determination of beta-blockers in human plasma and pharmaceutical wastewater samples. High clean-up and preconcentration factor are easily and rapidly feasible via this novel, cheap, and safe microextraction method, leading to high quality experimental data. It consists of two sequential dispersive liquid-liquid microextraction methods, accomplished via air/ultrasonic agitation and air agitation, respectively. In order to enrich the optimal values for the mentioned procedures, the Box-Behnken design (BBD) combined with the desirability function (DF) was used. The optimum values were found to be 11.0 % (w/v) of the salt amount, an initial pH value of 12.0, 103 μL of organic extractant phase, and 45 μL of aqueous extractant phase with pH value of 2.0, resulted in reasonable recovery percentages with a logical desirability. Under optimal experimental conditions, good linear ranges (3-2000 ng mL -1 for metoprolol and 2.5-2500 ng mL -1 for propranolol with the correlation of determinations (R 2 s) higher than 0.99) and low limits of detection (0.8 and 1.0 ng mL -1 for propranolol and metoprolol, respectively) were obtainable. Also, TDLLME-HPLC-UV provided good proper repeatabilities (relative standard deviations (RSDs) below 5.7 %, n = 3) and high enrichment factors (EFs) of 75-100. Graphical abstract TDLLME of beta-blockers from complicated matrices.

Development of a sensitive methodology for the analysis of chlorobenzenes in air by combination of solid-phase extraction and headspace solid-phase microextraction.

PubMed

Barro, Ruth; Ares, Sergio; Garcia-Jares, Carmen; Llompart, Maria; Cela, Rafael

2004-08-06

In this study, a combination of solid-phase extraction (SPE) and solid-phase microextraction (SPME) has been used to determine chlorobenzenes in air. Analytes were sampled by pumping a known volume of air through a porous polymer (Tenax TA). Then, the adsorbent was transferred into a glass vial and SPME was performed. The quantification was carried out using gas chromatography (GC)-electron-capture detection or GC-MS. Several SPME coatings (100 microm poly(dimethylsiloxane) (PDMS), 75 microm Carboxen (CAR)-PDMS, 65 microm PDMS-divinylbenzene (DVB), 65 microm PDMS-DVB and 85 microm polyacrylate (PA) were evaluated, obtaining the highest responses with Carbowax (CW)- PDMS for the most volatile chlorobenzenes, and with PDMS-DVB or CW-DVB fibers for the semivolatile compounds. To optimize some other factors that could affect the SPME step, a factorial design was used. Kinetic studies of the SPME process were also performed. Concerning the SPE step, breakthrough was studied, showing that 2.5 m3 of air could be processed without losses of the most volatile compounds. The performance of the method was evaluated. External calibration, which does not require the complete sampling process, demonstrated to be suitable, obtaining good linearity (R2 > 0.99) for all chlorobenzenes. Recovery studies were performed at two concentration levels (4 and 40 ng/m3), obtaining quantitative recoveries (>80%). Limits of detection at the sub ng/m3 were achieved for all the target compounds.

Rapid determination of 54 pharmaceutical and personal care products in fish samples using microwave-assisted extraction-Hollow fiber-Liquid/solid phase microextraction.

PubMed

Zhang, Yi; Guo, Wen; Yue, Zhenfeng; Lin, Li; Zhao, Fengjuan; Chen, Peijin; Wu, Weidong; Zhu, Hong; Yang, Bo; Kuang, Yanyun; Wang, Jiong

2017-04-15

In this paper, a simple, rapid, solvent-less and environmental friendliness microextraction method, microwave-assisted extraction-hollow fiber-liquid/solid phase microextraction (MAE-HF-L/SME), was developed for simultaneous extraction and enrichment of 54 trace hydrophilic/lipophilic pharmaceutical and personal care products (PPCPs) from fish samples. A solid-phase extraction material, solid-phase microextraction (SPME) fiber, was synthesized. The SPME fiber had a homogeneous, loose structure and good mechanical properties, and they exhibited a good adsorption capacity for most PPCPs selected. The material formed the basis for the method of MAE-HF-L/SME. A method of liquid chromatography-high resolution mass spectroscopy (LC-HRMS) for analysis of 54 PPCPs. Under optimal synthesis and extraction conditions, the limits of detection (LODs, n=3) and the limits of quantitation (LOQs, n=10) for the 54 PPCPs were between 0.01-0.50μg·kg -1 and 0.052.00μg·kg -1 , respectively. Percent recoveries and the relative standard deviations (RSDs) in spiked fish samples (n=6) were between 56.3%-119.9% and 0.3%-17.1%, respectively. The microextraction process of 54 PPCPs in MAE-HF-L/SME took approximately 12min. The method has a low matrix interference and high enrichment factor and may be applicable for determination of 54 different PPCPs in fish samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Deep eutectic solvent based gas-assisted dispersive liquid-phase microextraction combined with gas chromatography and flame ionization detection for the determination of some pesticide residues in fruit and vegetable samples.

PubMed

Farajzadeh, Mir Ali; Sattari Dabbagh, Masoumeh; Yadeghari, Adeleh

2017-05-01

In this study, a gas-assisted dispersive liquid-phase microextraction method using a deep eutectic solvent as the extraction solvent combined with gas chromatography and flame ionization detection was developed for the extraction and determination of some pesticide residues in vegetable and fruit juice samples. In this method, choline chloride and 4-chlorophenol at a molar ratio of 1:2 were mixed. By heating and vortexing, a clear, water-immiscible, and homogeneous liquid was formed. The obtained deep eutectic solvent was added to an aqueous solution of the analytes in a conical test tube. Air was bubbled into the aqueous solution and a cloudy solution was obtained. During this step, the analytes were extracted into the fine droplets of the extraction solvent. After centrifugation, an aliquot of the settled phase was injected into the separation system. Under the optimum extraction conditions, enrichment factors, and extraction recoveries were obtained in the ranges of 247-355 and 49-71%, respectively. The obtained values for the limits of detection and quantification were in the ranges of 0.24-1.4 and 0.71-4.2 μg/L, respectively. The proposed method is simple, fast, efficient, and inexpensive. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of in vivo solid phase microextraction for minimally invasive analysis of nonvolatile phytochemicals in Amazonian plants.

PubMed

Musteata, Florin Marcel; Sandoval, Manuel; Ruiz-Macedo, Juan C; Harrison, Kathleen; McKenna, Dennis; Millington, William

2016-08-24

Although solid phase microextraction (SPME) has been used extensively for fingerprinting volatile compounds emitted by plants, there are very few such reports for direct insertion SPME. In this research, direct contact of SPME probes with the interstitial fluid of plants was investigated as a method for phytochemical analysis. Medicinal plants from the Amazon have been the source of numerous drugs used in western medicine. However, a large number of species used in traditional medicine have not been characterized chemically, partly due to the difficulty of field work. In this project, the phytochemical composition of plants from several genera was fingerprinted by combining convenient field sampling by solid phase microextraction (SPME) with laboratory analysis by LC-MS. The new method was compared with classical sampling followed by liquid extraction (LE). SPME probes were prepared by coating stainless steel wires with a mixture of polyacrylonitrile and either RP-amide or HS-F5 silica particles. Sampling was performed by inserting the microextraction probes into various tissues of living plants in their natural environment. After in vivo extraction, the probes were sealed under vacuum and refrigerated until analyzed. The probes were desorbed in mobile phase and analyzed on a Waters Acquity UPLC with triple quadrupole mass spectrometer in positive ion mode. Twenty Amazonian plant species were sampled and unique metabolomic fingerprints were obtained. In addition, quantitative analysis was performed for previously identified compounds in three species. Comparison of the fingerprints obtained by in vivo SPME with those obtained by LE showed that 27% of the chromatographic features were unique to SPME, 57% were unique to LE, and 16% were common to both methods. In vivo SPME caused minimal damage to the plants, was much faster than traditional liquid extraction, and provided unique fingerprints for all investigated plants. SPME revealed unique chromatographic features, undetected by traditional extraction, although it produced only half as many peaks as ethanol extraction. Copyright © 2016 Elsevier B.V. All rights reserved.

Carrier mediated hollow fiber liquid phase microextraction combined with HPLC-UV for preconcentration and determination of some tetracycline antibiotics.

PubMed

Shariati, Shahab; Yamini, Yadollah; Esrafili, Ali

2009-02-01

In the present study, a simple and efficient preconcentration method was developed using carrier mediated three phase liquid phase microextraction prior to HPLC-UV for simultaneous extraction and determination of trace amounts of highly hydrophilic tetracycline antibiotics including tetracycline (TCN), oxytetracycline (OTCN) and doxycycline (DCN) in bovine milk, human plasma and water samples. For extraction, 11.0 mL of the aqueous sample containing TCNs and 0.05 M Na(2)HPO(4) (9.10.995). Finally, applicability of the proposed method was successfully confirmed by extraction and determination of the drugs in water and plasma samples as well as in bovine milk samples with low and high fat contents. Comparing to the traditional methods, the proposed method exhibits high sensitivity and high preconcentration factors as well as good precision. The extraction setup is simple and due to active transport of analytes, high cleanup effect and good selectivity are obtained in extraction process.

Quantitative Analysis of Bisphenol A Leached from Household Plastics by Solid-Phase Microextraction and Gas Chromatography-Mass Spectrometry (SPME-GC-MS)

ERIC Educational Resources Information Center

Johnson, Bettie Obi; Burke, Fernanda M.; Harrison, Rebecca; Burdette, Samantha

2012-01-01

The measurement of trace levels of bisphenol A (BPA) leached out of household plastics using solid-phase microextraction (SPME) with gas chromatography-mass spectrometry (GC-MS) is reported here. BPA is an endocrine-disrupting compound used in the industrial manufacture of polycarbonate plastic bottles and epoxy resin can liners. This experiment…

Solid-phase microextraction of hydrocarbons from water in a centrifuge

NASA Astrophysics Data System (ADS)

Ryabov, A. Yu.; Chuikin, A. V.; Velikov, A. A.

2016-06-01

The results of our study of solid-phase microextraction of substances using a centrifuge for determining the microquantities of hydrocarbon impurities in water are presented. The cartridge diameter, sorbent mass, and solvent volume were shown to affect the percent extraction of substances and the analytical signal intensity. The relationship between the cartridge geometry, the sorbent mass, and the solvent volume was considered.

Fast determination of octinoxate and oxybenzone uv filters in swimming pool waters by gas chromatography/mass spectrometry after solid-phase microextraction.

PubMed

Yılmazcan, Ö; Kanakaki, C; Izgi, B; Rosenberg, E

2015-07-01

A fast gas chromatography/mass spectrometry method was developed and validated for the analysis of the potential endocrine disrupters octinoxate and oxybenzone in swimming pool water samples based on the solvent-free solid-phase microextraction technique. The low-pressure gas chromatography/mass spectrometry method used for the fast identification of UV filter substances was compared to a conventional method in terms of sensitivity and speed. The fast method proposed resulted in 2 min runs, leading to an eightfold decrease in the total analysis time and a sevenfold improvement in detection limits. The main parameters affecting the solid-phase microextraction process were also studied in detail and the optimized conditions were as follows: fiber coating, polyacrylate; extraction mode, direct immersion; extraction temperature, 25°C; sample volume, 5 mL; extraction time 45 min; pH 6.5. Under the optimized conditions, a linear response was obtained in the concentration range of 0.5-25 μg/L with correlation coefficients in the range 0.990-0.999. The limits of detection were 0.17-0.29 μg/L, and the recoveries were 80-83%. Combined method uncertainty was assessed and found to be less than 7% for both analytes for concentrations equal to or higher than 5 μg/L. Pool water samples were analyzed to demonstrate the applicability of the proposed method. Neither octinoxate nor oxybenzone were detected in the swimming pool water samples at concentrations above the respective limits of detection. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Facile preparation of multifunctional carbon nanotube/magnetite/polyaniline nanocomposite offering a strong option for efficient solid-phase microextraction coupled with GC-MS for the analysis of phenolic compounds.

PubMed

Tafazoli, Zahra; Azar, Parviz Aberoomand; Tehrani, Mohammad Saber; Husain, Syed Waqif

2018-04-20

The aim of this study the synthesis of a highly efficient organic-inorganic nanocomposite. In this research, the carbon nanotube/magnetite/polyaniline nanocomposite was successfully prepared through a facile route. Monodisperse magnetite nanospheres were prepared through the coprecipitation route, and polyaniline nanolayer as a modified shell with a high surface area was synthesized by an in situ growth route and characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and energy dispersive X-ray spectroscopy. The prepared nanocomposite was immobilized on a stainless-steel wire for the fabrication of the solid-phase microextraction fiber. The combination of headspace solid-phase microextraction using carbon nanotube/magnetite/polyaniline nanocomposite fiber with gas chromatography and mass spectrometry can achieve a low limit of detection and can be applied to determine phenolic compounds in water samples. The effects of the extraction and desorption parameters including extraction temperature and time, ionic strength, stirring rate, pH, and desorption temperature and time have been studied. Under the optimum conditions, the dynamic linear range was 0.01-500 ng mL -1 and the limits of detection of phenol, 4-chlorophenol, 2,6-dichlorophenol, and 2,4,6-trichlorophenol were the lowest (0.008 ng mL -1 ) for three times. The coefficient of determination of all calibration curves was more than 0.990. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Multiple monolithic fiber solid-phase microextraction based on a polymeric ionic liquid with high-performance liquid chromatography for the determination of steroid sex hormones in water and urine.

PubMed

Liao, Keren; Mei, Meng; Li, Haonan; Huang, Xiaojia; Wu, Cuiqin

2016-02-01

The development of a simple and sensitive analytical approach that combines multiple monolithic fiber solid-phase microextraction with liquid desorption followed by high-performance liquid chromatography with diode array detection is proposed for the determination of trace levels of seven steroid sex hormones (estriol, 17β-estradiol, testosterone, ethinylestradiol, estrone, progesterone and mestranol) in water and urine matrices. To extract the target analytes effectively, multiple monolithic fiber solid-phase microextraction based on a polymeric ionic liquid was used to concentrate hormones. Several key extraction parameters including desorption solvent, extraction and desorption time, pH value and ionic strength in sample matrix were investigated in detail. Under the optimal experimental conditions, the limits of detection were found to be in the range of 0.027-0.12 μg/L. The linear range was 0.10-200 μg/L for 17β-estradiol, 0.25-200 μg/L estriol, ethinylestradiol and estrone, and 0.50-200 μg/L for the other hormones. Satisfactory linearities were achieved for analytes with the correlation coefficients above 0.99. Acceptable method reproducibility was achieved by evaluating the repeatability and intermediate precision with relative standard deviations of both less than 8%. The enrichment factors ranged from 54- to 74-fold. Finally, the proposed method was successfully applied to the analysis of steroid sex hormones in environmental water samples and human urines with spiking recoveries ranged from 75.6 to 116%. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Novel strategies for sample preparation in forensic toxicology.

PubMed

Samanidou, Victoria; Kovatsi, Leda; Fragou, Domniki; Rentifis, Konstantinos

2011-09-01

This paper provides a review of novel strategies for sample preparation in forensic toxicology. The review initially outlines the principle of each technique, followed by sections addressing each class of abused drugs separately. The novel strategies currently reviewed focus on the preparation of various biological samples for the subsequent determination of opiates, benzodiazepines, amphetamines, cocaine, hallucinogens, tricyclic antidepressants, antipsychotics and cannabinoids. According to our experience, these analytes are the most frequently responsible for intoxications in Greece. The applications of techniques such as disposable pipette extraction, microextraction by packed sorbent, matrix solid-phase dispersion, solid-phase microextraction, polymer monolith microextraction, stir bar sorptive extraction and others, which are rapidly gaining acceptance in the field of toxicology, are currently reviewed.

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

Development of an Alternative Mixed Odor Delivery Device (MODD) for Canine Training

DTIC Science & Technology

2017-05-10

solid phase microextraction (SPME) and analysis by gas chromatography / mass spectrometry (GC/MS). Like the computational modeling, the laboratory...outlet was extracted by solid phase microextraction (SPME) and analyzed by gas chromatography with mass spectrometry (GC/MS). A polydimethylsiloxane...Menning and H. Ostmark, "Detection of liquid and homemade explosives: What do we need to know about their properties?," in Detection of Liquid

Comparison between solid phase microextraction (SPME) and hollow fiber liquid phase microextraction (HFLPME) for determination of extractables from post-consumer recycled PET into food simulants.

PubMed

Oliveira, Éder Costa; Echegoyen, Yolanda; Cruz, Sandra Andrea; Nerin, Cristina

2014-09-01

Hollow fiber liquid phase microextraction (HFLPME) and solid phase microextraction (SPME) methods for pre-concentration of contaminants (toluene, benzophenone, tetracosane and chloroform) in food simulants were investigated. For HFLPME 1-heptanol, 2-octanone and dibutyl-ether were studied as extracting solvents. Analysis by gas chromatography coupled to mass spectrometry (GC-MS), flame ionization (GC-FID) and electron capture detectors (GC-ECD) were carried out. In addition, the methods were employed to evaluate the safety in use of a PET material after the recycling process (comprising washing, extrusion and solid state polymerization (SSP)) through extractability studies of the contaminants using 10% (v/v) ethanol in deionized water and 3% (w/v) acetic acid in deionized water as food simulants in different conditions: 10 days at 40°C and 2h at 70°C. The HFLPME preconcentration method provided increased sensitivity when compared to the SPME method and allowed to analyze concentration levels below 10 µg surrogate per kg food simulant. The results of the extractability studies showed considerable reductions after the extrusion and SSP processes and indicated the compliance with regulations for using recycled PET in contact with food. Copyright © 2014 Elsevier B.V. All rights reserved.

Quantitative Determining of Ultra-Trace Aluminum Ion in Environmental Samples by Liquid Phase Microextraction Assisted Anodic Stripping Voltammetry.

PubMed

Zhang, Liuyang; Luo, Jinju; Shen, Xinyu; Li, Chunya; Wang, Xian; Nie, Bei; Fang, Huaifang

2018-05-10

Direct detecting of trace amount Al(III) in aqueous solution by stripping voltammetry is often frustrated by its irreversible reduction, resided at −1.75 V (vs. Ag/AgCl reference), which is in a proximal potential of proton reduction. Here, we described an electroanalytical approach, combined with liquid phase microextraction (LPME) using ionic liquid (IL), to quantitatively assess trace amount aluminum in environmental samples. The Al(III) was caged by 8-hydroxyquinoline, forming a superb hydrophobic metal⁻chelate, which sequentially transfers and concentrates in the bottom layer of IL-phase during LPME. The preconcentrated Al(III) was further analyzed by a square-wave anodic stripping voltammetry (SW-ASV). The resulting Al-deposited electrodes were characterized by scanning electron microscopy and powder X-ray diffraction, showing the intriguing amorphous nanostructures. The method developed provides a linear calibration ranging from 0.1 to 1.2 ng L −1 with a correlation coefficient of 0.9978. The LOD attains as low as 1 pmol L −1 , which reaches the lowest report for Al(III) detection using electroanalytical techniques. The applicable methodology was implemented for monitoring Al(III) in commercial distilled water.

Headspace Solid-Phase Microextraction and Ultrasonic Extraction with the Solvent Sequences in Chemical Profiling of Allium ursinum L. Honey.

PubMed

Jerković, Igor; Kuś, Piotr M

2017-11-06

A volatile profile of ramson (wild garlic, Allium ursinum L.) honey was investigated by headspace solid-phase microextraction (HS-SPME) and ultrasonic solvent extraction (USE) followed by gas chromatography and mass spectrometry (GC-FID/GC-MS) analyses. The headspace was dominated by linalool derivatives: cis - and trans -linalool oxides (25.3%; 9.2%), hotrienol (12.7%), and linalool (5.8%). Besides direct extraction with dichloromethane and pentane/diethyl ether mixture (1:2, v / v ), two solvent sequences (I: pentane → diethyl ether; II: pentane → pentane/diethyl ether (1:2, v / v ) → dichloromethane) were applied. Striking differences were noted among the obtained chemical profiles. The extracts with diethyl ether contained hydroquinone (25.8-36.8%) and 4-hydroxybenzoic acid (11.6-16.6%) as the major compounds, while ( E )-4-(r-1',t-2',c-4'-trihydroxy-2',6',6'-trimethylcyclohexyl)but-3-en-2-one predominated in dichloromethane extracts (18.3-49.1%). Therefore, combination of different solvents was crucial for the comprehensive investigation of volatile organic compounds in this honey type. This particular magastigmane was previously reported only in thymus honey and hydroquinone in vipers bugloss honey, while a combination of the mentioned predominant compounds is unique for A. ursinum honey.

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.

Evaluation of solid-phase microextraction desorption parameters for fast GC analysis of cocaine in coca leaves.

PubMed

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

2006-08-01

By its simplicity and rapidity, solid-phase microextraction (SPME) appears as an interesting alternative for sample introduction in fast gas chromatography (fast GC). This combination depends on numerous parameters affecting the desorption step (i.e., the release of compounds from the SPME fiber coating to the GC column). In this study, different liner diameters, injection temperatures, and gas flow rates are evaluated to accelerate the thermal desorption process in the injection port. This process is followed with real-time direct coupling a split/splitless injector to a mass spectrometer by means of a short capillary. It is shown that an effective, quantitative, and rapid transfer of cocaine (COC) and cocaethylene (CE) is performed with a 0.75-mm i.d. liner, at 280 degrees C and 4 mL/min gas flow rate. The 7-microm polydimethylsiloxane (PDMS) coating is selected for combination with fast GC because the 100-microm PDMS fiber presents some limitations caused by fiber bleeding. Finally, the developed SPME-fast GC method is applied to perform in less than 5 min, the quantitation of COC extracted from coca leaves by focused microwave-assisted extraction. An amount of 7.6 +/- 0.5 mg of COC per gram of dry mass is found, which is in good agreement with previously published results.

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.

Headspace sorptive solid phase microextraction (HS-SPME) combined with a spectrophotometry system: A simple glass devise for extraction and simultaneous determination of cyanide and thiocyanate in environmental and biological samples.

PubMed

Al-Saidi, H M; Al-Harbi, Sami A; Aljuhani, E H; El-Shahawi, M S

2016-10-01

A simple, low cost and efficient headspace sorptive solid phase microextraction (HS-SPME) method for determination of cyanide has been developed. The system comprises of a glass tube with two valves and a moveable glass slide fixed at its centre. It includes an acceptor phase polyurethane foam treated mercury (II) dithizonate [Hg(HDz)2-PUF] complex fixed inside by a septum cap in a cylindrical configuration (5.0cm length and 1.0cm diameter). The extraction is based upon the contact of the acceptor phase to the headspace and subsequently measuring the absorbance of the recovered mercury (II) dithizonate from PUFs sorbent. Unlike other HSSE, extraction and back - extractions was carried out in a closed system, thereby improving the analytical performance by preventing the analyte loss. Under the optimized conditions, a linear calibration plot in the range of 1.0-50.0µmolL(-1) was achieved with limits of detection (LOD) and quantification (LOQ) of 0.34, 1.2µmolL(-1) CN(-), respectively. Simultaneous analysis of cyanide and thiocyanate in saliva was also performed with satisfactory recoveries. Copyright © 2016. Published by Elsevier B.V.

Ultrasound-assisted magnetic dispersive solid-phase microextraction: A novel approach for the rapid and efficient microextraction of naproxen and ibuprofen employing experimental design with high-performance liquid chromatography.

PubMed

Ghorbani, Mahdi; Chamsaz, Mahmoud; Rounaghi, Gholam Hossein

2016-03-01

A simple, rapid, and sensitive method for the determination of naproxen and ibuprofen in complex biological and water matrices (cow milk, human urine, river, and well water samples) has been developed using ultrasound-assisted magnetic dispersive solid-phase microextraction. Magnetic ethylendiamine-functionalized graphene oxide nanocomposite was synthesized and used as a novel adsorbent for the microextraction process and showed great adsorptive ability toward these analytes. Different parameters affecting the microextraction were optimized with the aid of the experimental design approach. A Plackett-Burman screening design was used to study the main variables affecting the microextraction process, and the Box-Behnken optimization design was used to optimize the previously selected variables for extraction of naproxen and ibuprofen. The optimized technique provides good repeatability (relative standard deviations of the intraday precision 3.1 and 3.3, interday precision of 5.6 and 6.1%), linearity (0.1-500 and 0.3-650 ng/mL), low limits of detection (0.03 and 0.1 ng/mL), and a high enrichment factor (168 and 146) for naproxen and ibuprofen, respectively. The proposed method can be successfully applied in routine analysis for determination of naproxen and ibuprofen in cow milk, human urine, and real water samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous determination of several phytohormones in natural coconut juice by hollow fiber-based liquid-liquid-liquid microextraction-high performance liquid chromatography.

PubMed

Wu, Yunli; Hu, Bin

2009-11-06

A simple, selective, sensitive and inexpensive method of hollow fiber-based liquid-liquid-liquid microextraction (HF-LLLME) combined with high performance liquid chromatography (HPLC)-ultraviolet (UV) detection was developed for the determination of four acidic phytohormones (salicylic acid (SA), indole-3-acetic acid (IAA), (+/-) abscisic acid (ABA) and (+/-) jasmonic acid (JA)) in natural coconut juice. To the best of our knowledge, this is the first report on the use of liquid phase microextraction (LPME) as a sample pretreatment technique for the simultaneous analysis of several phytohormones. Using phenetole to fill the pores of hollow fiber as the organic phase, 0.1molL(-1) NaOH solution in the lumen of hollow fiber as the acceptor phase and 1molL(-1) HCl as the donor phase, a simultaneous preconcentration of four target phytohormones was realized. The acceptor phase was finally withdrawn into the microsyringe and directly injected into HPLC for the separation and quantification of the target phytohormones. The factors affecting the extraction efficiency of four phytohormones by HF-LLLME were optimized with orthogonal design experiment, and the data was analyzed by Statistical Product and Service Solutions (SPSS) software. Under the optimized conditions, the enrichment factors for SA, IAA, ABA and JA were 243, 215, 52 and 48, with the detection limits (S/N=3) of 4.6, 1.3, 0.9ngmL(-1) and 8.8 microg mL(-1), respectively. The relative standard deviations (RSDs, n=7) were 7.9, 4.9, 6.8% at 50ngmL(-1) level for SA, IAA, ABA and 8.4% at 500 microg mL(-1) for JA, respectively. To evaluate the accuracy of the method, the developed method was applied for the simultaneous analysis of several phytohormones in five natural coconut juice samples, and the recoveries for the spiked samples were in the range of 88.3-119.1%.

Application of non-ionic surfactant as a developed method for the enhancement of two-phase solvent bar microextraction for the simultaneous determination of three phthalate esters from water samples.

PubMed

Bandforuzi, Samereh Ranjbar; Hadjmohammadi, Mohammad Reza

2018-08-03

The extraction of phthalate esters (PEs) from aqueous matrices using two-phase solvent bar microextraction by organic micellar phase was investigated. A short hollow fiber immobilized with reverse micelles of Brij 35 surfactant in 1-octanol was served as the solvent bar for microextraction. Experimental results show that the extraction efficiency were much higher using two-phase solvent bar microextraction based on non-ionic surfactant than conventional two-phase solvent bar microextraction because of a positive effect of surfactant-containing extraction phase in promoting the partition process by non-ionic intermolecular forces such as polar and hydrophobicity interactions. The nature of the extraction solvent, type and concentration of non-ionic surfactant, extraction time, sample pH, temperature, stirring rate and ionic strength were the effecting parameters which optimized to obtain the highest extraction recovery. Analysis of recovered analytes was carried out with high performance liquid chromatography coupled with ultraviolet detection (HPLC-UV). Under the optimum conditions, linearity was observed in the range of 1-800 ng mL -1 for dimethylphthalate (DMP) and 0.5-800 ng mL -1 for diethylphthalate (DEP) and di-n-butyl phthalate (DBP) with correlation determination values above 0.99 for them. The limits of detection and quantification were ranged from 0.012 to 0.03 ng mL -1 and 0.04-0.1 ng mL -1 , respectively. The ranges of intra-day and inter-day RSD (n = 3) at 20 ng mL -1 of PEs were 1.8-2.1% and 2.1-2.6%, respectively. Results showed that developed method can be a very powerful, innovative and promising sample preparation technique in PEs analysis from environmental and drinking water samples. Copyright © 2018. Published by Elsevier B.V.

A rapid space-resolved solid-phase microextraction method as a powerful tool to determine contaminants in wine based on their volatility.

PubMed

Liu, Min; Peng, Qing-Qing; Chen, Yu-Feng; Tang, Qian; Feng, Qing

2015-06-01

A novel space-resolved solid phase microextraction (SR-SPME) technique was developed to facilitate simultaneously analyte monitoring within heterogeneous samples. Graphene (G) and graphene oxide (GO) were coated separately to the segmented fibers which were successfully used for the solid-phase microextraction of two contaminants with dramatically different volatility: 2,4,6-trichloroanisole (TCA) and dibutyl phthalate (DBP). The space-resolved fiber showed good precision (5.4%, 6.8%), low detection limits (0.3ng/L, 0.3ng/L), and wide linearity (1.0-250.0ng/L, 1.0-250.0ng/L) under the optimized conditions for TCA and DBP, respectively. The method was applied to simultaneous analysis of the two contaminates with satisfactory recoveries, which were 96.96% and 98.20% for wine samples. Copyright © 2014 Elsevier Ltd. All rights reserved.

An innovative method for analysis of Pb (II) in rice, milk and water samples based on TiO2 reinforced caprylic acid hollow fiber solid/liquid phase microextraction.

PubMed

Bahar, Shahriyar; Es'haghi, Zarrin; Nezhadali, Azizollah; Banaei, Alireza; Bohlooli, Shahab

2017-04-15

In the present study, nano-sized titanium oxides were applied for preconcentration and determination of Pb(II) in aqueous samples using hollow fiber based solid-liquid phase microextraction (HF-SLPME) combined with flame atomic absorption spectrometry (FAAS). In this work, the nanoparticles dispersed in caprylic acid as an extraction solvent was placed into a polypropylene porous hollow fiber segment supported by capillary forces and sonification. This membrane was in direct contact with solutions containing Pb (II). The effect of experimental conditions on the extraction, such as pH, stirring rate, sample volume, and extraction time were optimized. Under the optimal conditions, the performance of the proposed method was investigated for the determination of Pb (II) in food and water samples. The method was linear in the range of 0.6-3000μgmL -1 . The relative standard deviations and relative recovery of Pb (II) was 4.9% and 99.3%, respectively (n=5). Copyright © 2016 Elsevier Ltd. All rights reserved.

Heat-shrink tubing as a solid-phase microextraction coating for the enrichment and determination of phthalic acid esters.

PubMed

Luo, Xi; He, Chengxia; Zhang, Feifang; Wang, Hailong; Yang, Bingcheng; Liang, Xinmiao

2014-12-01

Heat-shrink tubing, which shrinks in one plane only (its diameter) when heated, commonly used for sealing protection in electrical engineering, was found to be able to function as a solid-phase microextraction coating. Its utility was demonstrated for the determination of phthalic acid esters in an aqueous solution combined with high-performance liquid chromatography equipped with a UV absorbance detector. The preparation procedure was rather simple and only ∼10 min was needed. The fiber cost is extremely low (∼10 cent each). The parameters affecting the extraction were optimized. Heat-shrink tubing fiber exhibited a significant enrichment effect for the three examined phthalic acid esters and up to 931-fold enrichment factor was obtained. The limit of detection was <10 μg/L for all analytes. The operation repeatability and fiber-to-fiber reproducibility were 1.2-8.3 and 5.4-9.1%, respectively. It was successfully applied for the analysis of bottled drinking water with recoveries ranging from 90.1-100.5%. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ultrasound assisted microextraction-nano material solid phase dispersion for extraction and determination of thymol and carvacrol in pharmaceutical samples: experimental design methodology.

PubMed

Roosta, Mostafa; Ghaedi, Mehrorang; Daneshfar, Ali; Sahraei, Reza

2015-01-15

In the present study, for the first time, a new extraction method based on "ultrasound assisted microextraction-nanomaterial solid phase dispersion (UAME-NMSPD)" was developed to preconcentrate the low quantity of thymol and carvacrol in pharmaceutical samples prior to their HPLC-UV separation/determination. The analytes were accumulated on nickel sulfide nanomaterial loaded on activated carbon (NiS-NP-AC) that with more detail identified by XRD, FESEM and UV-vis technique. Central composite design (CCD) combined with desirability function (DF) was used to search for optimum operational conditions. Working under optimum conditions specified as: 10 min ultrasonic time, pH 3, 0.011 g of adsorbent and 600 μL extraction solvent) permit achievement of high and reasonable linear range over 0.005-2.0 μg mL(-1) (r(2)>0.9993) with LOD of thymol and carvacrol as 0.23 and 0.21 μg L(-1), respectively. The relative standard deviations (RSDs) were less than 4.93% (n=3). Copyright © 2014 Elsevier B.V. All rights reserved.

Polymeric ionic liquid bucky gels as sorbent coatings for solid-phase microextraction.

PubMed

Zhang, Cheng; Anderson, Jared L

2014-05-30

Novel cross-linked polymeric ionic liquid (PIL) bucky gels were formed by free-radical polymerization of polymerizable ionic liquids gelled with multi-walled carbon nanotubes (MWCNT) and used as sorbent coatings for solid-phase microextraction (SPME). The combination of PIL with MWCNTs significantly enhanced the π-π interaction between the sorbent coatings and the aromatic analytes. Compared to the neat PIL-based sorbent coating, the PIL bucky gel sorbent coatings demonstrated higher extraction efficiency for the extraction of polycyclic aromatic hydrocarbons (PAHs). A partitioning extraction mechanism was observed for the PIL/MWCNT-based sorbent coatings indicating that the addition of MWCNTs did not seem to affect the extraction mechanism of the sorbent coating. The analyte-to-coating partition coefficients (logKfs) were estimated and the limits of detection (LOD) for selected PIL bucky gel sorbent coating were determined to be in the range of 1-2.5 ng L(-1). Recovery studies were also performed for PAHs in river and tap water to validate the applicability of the developed method. Copyright © 2014 Elsevier B.V. All rights reserved.

Bio-dispersive liquid liquid microextraction based on nano rhaminolipid aggregates combined with magnetic solid phase extraction using Fe3O4@PPy magnetic nanoparticles for the determination of methamphetamine in human urine.

PubMed

Haeri, Seyed Ammar; Abbasi, Shahryar; Sajjadifar, Sami

2017-09-15

In the present investigation, extraction and preconcentration of methamphetamine in human urine samples was carried out using a novel bio-dispersive liquid liquid microextraction (Bio-DLLME) technique coupled with magnetic solid phase extraction (MSPE). Bio-DLLME is a kind of microextraction technique based nano-materials which have potential capabilities in many application fields. Bio-DLLME is based on the use of a binary part system consisting of methanol and nano rhaminolipid biosurfactant. Use of this binary mixture is ecologically accepted due to their specificity, biocompatibility and biodegradable nature. The potential of nano rhaminolipid biosurfactant as a biological agent in the extraction of organic compounds has been investigated in recent years. They are able to partition at the oil/water interfaces and reduce the interfacial tension in order to increase solubility of hydrocarbons. The properties of the prepared Fe 3 O 4 @PPy magnetic nanoparticles were characterized using Fourier transform infrared spectroscopy and X-ray diffraction methods The influences of the experimental parameters on the quantitative recovery of analyte were investigated. Under optimized conditions, the enrichment factor was 310, the calibration graph was linear in the methamphetamine concentration range from 1 to 60μgL -1 , with a correlation coefficient of 0.9998. The relative standard deviations for six replicate measurements was 5.2%. Copyright © 2017 Elsevier B.V. All rights reserved.

Simultaneous extraction and determination of albendazole and triclabendazole by a novel syringe to syringe dispersive liquid phase microextraction-solidified floating organic drop combined with high performance liquid chromatography.

PubMed

Asadi, Mohammad; Dadfarnia, Shayessteh; Haji Shabani, Ali Mohammad

2016-08-17

A syringe to syringe dispersive liquid phase microextraction-solidified floating organic drop was introduced and used for the simultaneous extraction of trace amounts of albendazole and triclabendazole from different matrices. The extracted analytes were determined by high performance liquid chromatography along with fluorescence detection. The analytical parameters affecting the microextraction efficiency including the nature and volume of the extraction solvent, sample volume, sample pH, ionic strength and the cycles of extraction were optimized. The calibration curves were linear in the range of 0.1-30.0 μg L(-1) and 0.2-30.0 μg L(-1) with determination coefficients of 0.9999 and 0.9998 for albendazole and triclabendazole respectively. The detection limits defined as three folds of the signal to noise ratio were found to be 0.02 μg L(-1) for albendazole and 0.06 μg L(-1) for triclabendazole. The inter-day and intra-day precision (RSD%) for both analytes at three concentration levels (0.5, 2.0 and 10.0 μg L(-1)) were in the range of 6.3-10.1% and 5.0-7.5% respectively. The developed method was successfully applied to determine albendazole and triclabendazole in water, cow milk, honey, and urine samples. Copyright © 2016. Published by Elsevier B.V.

Application of hollow fiber-supported liquid-phase microextraction coupled with HPLC for the determination of guaifenesin enantiomer-protein binding.

PubMed

Hatami, Mehdi; Farhadi, Khalil

2012-07-01

A hollow fiber liquid-phase microextraction technique coupled with high-performance liquid chromatography with fluorescence detection was employed for determination and evaluation of the binding characteristics of drugs to bovine serum albumin (BSA). Enantiomers of guaifenesin (an expectorant drug) were investigated as a model system. After optimization of some influencing parameters on microextraction, the proposed method was used for calculation of the target drug distribution coefficient between n-octanol and the buffer solution as well as study of drug-BSA binding in physiological conditions. The developed method shows a new, improved and simple procedure for determination of free drug concentration in biological fluids and the extent of drug-protein binding. Copyright © 2011 John Wiley & Sons, Ltd.

The current role of on-line extraction approaches in clinical and forensic toxicology.

PubMed

Mueller, Daniel M

2014-08-01

In today's clinical and forensic toxicological laboratories, automation is of interest because of its ability to optimize processes, to reduce manual workload and handling errors and to minimize exposition to potentially infectious samples. Extraction is usually the most time-consuming step; therefore, automation of this step is reasonable. Currently, from the field of clinical and forensic toxicology, methods using the following on-line extraction techniques have been published: on-line solid-phase extraction, turbulent flow chromatography, solid-phase microextraction, microextraction by packed sorbent, single-drop microextraction and on-line desorption of dried blood spots. Most of these published methods are either single-analyte or multicomponent procedures; methods intended for systematic toxicological analysis are relatively scarce. However, the use of on-line extraction will certainly increase in the near future.

Microextraction in a tetrabutylammonium bromide/ammonium sulfate aqueous two-phase system and electrohydrodynamic generation of a micro-droplet.

PubMed

Song, Young Soo; Choi, Young Hoon; Kim, Do Hyun

2007-08-31

Microextraction of methyl orange in the aqueous two-phase system (ATPS) formed by dissolving tetrabutylammonium bromide (TBAB) and ammonium sulfate (AS) is reported. Methyl orange was transported from the AS-rich phase to TBAB-rich phase across the interface of the two immiscible phases. The electrohydrodynamic effect on the shape of the interface of two immiscible flows was also observed by applying dc voltage at the T-junction of the microchannel and the generation of a droplet of AS-rich phase was observed when the potential difference between positive and negative electrodes exceeds a threshold voltage. The minimum voltage necessary for the droplet generation depends on pH due to the degree of dissociation and charge accumulation.

Application of Solid Phase Microextraction Coupled with Gas Chromatography/Mass Spectrometry as a Rapid Method for Field Sampling and Analysis of Chemical Warfare Agents and Toxic Industrial Chemicals

DTIC Science & Technology

2003-01-01

PHASE MICROEXTRACTION COUPLED WITH GAS CHROMATOGRAPHY/MASS SPECTROMETRY AS A RAPID METHOD FOR FIELD SAMPLING AND ANALYSIS OF CHEMICAL WARFARE AGENTS...SAMPLING AND ANALYSIS OF CHEMICAL WARFARE AGENTS AND TOXIC INDUSTRIAL CHEMICALS 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...GAS CHROMATOGRAPHY/MASS SPECTROMETRY AS A RAPID METHOD FOR FIELD SAMPLING AND ANALYSIS OF CHEMICAL WARFARE AGENTS AND TOXIC INDUSTRIAL CHEMICALS

Separation of cucurbitane triterpenoids from bitter melon drinks and determination of partition coefficients using vortex-assisted dispersive liquid-phase microextraction followed by UHPLC analysis

USDA-ARS?s Scientific Manuscript database

A rapid, effective technique applying vortex-assisted liquid–liquid microextraction (VALLME) prior to ultra high performance liquid chromatography-evaporating light scattering detectection/ mass spectroscopy (UHPLC-ELSD/MS) determination was developed for the analysis of four cucurbitane triterpenoi...

Comparison of mass spectrometry-based electronic nose and solid phase microextraction gas chromatography-mass spectrometry technique to assess infant formula oxidation.

PubMed

Fenaille, François; Visani, Piero; Fumeaux, René; Milo, Christian; Guy, Philippe A

2003-04-23

Two headspace techniques based on mass spectrometry detection (MS), electronic nose, and solid phase microextraction coupled to gas chromatography-mass spectrometry (SPME-GC/MS) were evaluated for their ability to differentiate various infant formula powders based on changes of their volatiles upon storage. The electronic nose gave unresolved MS fingerprints of the samples gas phases that were further submitted to principal component analysis (PCA). Such direct MS recording combined to multivariate treatment enabled a rapid differentiation of the infant formulas over a 4 week storage test. Although MS-based electronic nose advantages are its easy-to-use aspect and its meaningful data interpretation obtained with a high throughput (100 samples per 24 h), its greatest disadvantage is that the present compounds could not be identified and quantified. For these reasons, a SPME-GC/MS measurement was also investigated. This technique allowed the identification of saturated aldehydes as the main volatiles present in the headspace of infant milk powders. An isotope dilution assay was further developed to quantitate hexanal as a potential indicator of infant milk powder oxidation. Thus, hexanal content was found to vary from roughly 500 and 3500 microg/kg for relatively non-oxidized and oxidized infant formulas, respectively.

Silicon carbide nanomaterial as a coating for solid-phase microextraction.

PubMed

Tian, Yu; Feng, Juanjuan; Wang, Xiuqin; Sun, Min; Luo, Chuannan

2018-01-26

Silicon carbide has excellent properties, such as corrosion resistance, high strength, oxidation resistance, high temperature, and so on. Based on these properties, silicon carbide was coated on stainless-steel wire and used as a solid-phase microextraction coating, and polycyclic aromatic hydrocarbons were employed as model analytes. Using gas chromatography, some important factors that affect the extraction efficiency were optimized one by one, and an analytical method was established. The analytical method showed wide linear ranges (0.1-30, 0.03-30, and 0.01-30 μg/L) with satisfactory correlation coefficients (0.9922-0.9966) and low detection limits (0.003-0.03 μg/L). To investigate the practical application of the method, rainwater and cigarette ash aqueous solution were collected as real samples for extraction and detection. The results indicate that silicon carbide has excellent application in the field of solid-phase microextraction. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ionic Liquid-Bonded Fused Silica as a New Solid-Phase Microextraction Fiber for the Liquid Chromatographic Determination of Bisphenol A as an Endocrine Disruptor.

PubMed

Mohammadnezhad, Nasim; Matin, Amir Abbas; Samadi, Naser; Shomali, Ashkan; Valizadeh, Hassan

2017-01-01

Linear ionic liquid bonded to fused silica and its application as a solid-phase microextraction fiber for the extraction of bisphenol A (BPA) from water samples were studied. After optimization of microextraction conditions (15 mL sample volume, extraction time of 40 min, extraction temperature of 30 ± 1°C, 300 μL acetonitrile as the desorption solvent, and desorption time of 7 min), the fiber was used to extract BPA from packed mineral water, followed by HPLC-UV on an XDB-C18 column (150 × 4.6 mm id, 3.5 μm particle) with a mobile phase of acetonitrile-water (45 + 55%, v/v) and flow rate of 1 mL . min-1). A low LOD (0.20 μg . L-1) and good linearity (0.9977) in the calibration graph indicated that the proposed method was suitable for the determination of BPA.

Hollow-fiber liquid-phase microextraction coupled with miniature capillary electrophoresis for the trace analysis of four aliphatic aldehydes in water samples.

PubMed

Li, Ying; Yi, Fan; Zheng, Yiliang; Wang, Yu; Ye, Jiannong; Chu, Qingcui

2015-08-01

An environmentally friendly method for the trace analysis of four aliphatic aldehydes as water disinfection byproducts has been developed based on hollow-fiber liquid-phase microextraction followed by miniature capillary electrophoresis with amperometric detection. After derivatization with 2-thiobarbituric acid, four aliphatic aldehydes (formaldehyde, acetaldehyde, propylaldehyde, and butyraldehyde) became detectable by the amperometric detector. Under the optimum conditions, four aliphatic aldehydes can be well separated from the coexisting interferents as well as their homologs (pentanal, glyoxal, and methyl-glyoxal), and the limits of detection (S/N = 3) could reach sub-nanogram-per-milliliter level based on hollow-fiber liquid-phase microextraction. The proposed method has been applied for the analyses of above four aliphatic aldehydes in different water samples such as drinking water, tap water, and river water, and the average recoveries were in the range of 90-113%, providing an alternative to conventional and microchip capillary electrophoresis approaches. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of needle trap micro-extraction and solid-phase micro-extraction: Obtaining comprehensive information on volatile emissions from in vitro cultures.

PubMed

Oertel, Peter; Bergmann, Andreas; Fischer, Sina; Trefz, Phillip; Küntzel, Anne; Reinhold, Petra; Köhler, Heike; Schubert, Jochen K; Miekisch, Wolfram

2018-05-14

Volatile organic compounds (VOCs) emitted from in vitro cultures may reveal information on species and metabolism. Owing to low nmol L -1 concentration ranges, pre-concentration techniques are required for gas chromatography-mass spectrometry (GC-MS) based analyses. This study was intended to compare the efficiency of established micro-extraction techniques - solid-phase micro-extraction (SPME) and needle-trap micro-extraction (NTME) - for the analysis of complex VOC patterns. For SPME, a 75 μm Carboxen®/polydimethylsiloxane fiber was used. The NTME needle was packed with divinylbenzene, Carbopack X and Carboxen 1000. The headspace was sampled bi-directionally. Seventy-two VOCs were calibrated by reference standard mixtures in the range of 0.041-62.24 nmol L -1 by means of GC-MS. Both pre-concentration methods were applied to profile VOCs from cultures of Mycobacterium avium ssp. paratuberculosis. Limits of detection ranged from 0.004 to 3.93 nmol L -1 (median = 0.030 nmol L -1 ) for NTME and from 0.001 to 5.684 nmol L -1 (median = 0.043 nmol L -1 ) for SPME. NTME showed advantages in assessing polar compounds such as alcohols. SPME showed advantages in reproducibility but disadvantages in sensitivity for N-containing compounds. Micro-extraction techniques such as SPME and NTME are well suited for trace VOC profiling over cultures if the limitations of each technique is taken into account. Copyright © 2018 John Wiley & Sons, Ltd.

Identification and quantification of odours from oxobiodegradable polyethylene oxidised under a free radical flow by headspace solid-phase microextraction followed by gas chromatography-olfactometry-mass spectrometry.

PubMed

Wrona, Magdalena; Vera, Paula; Pezo, Davinson; Nerín, Cristina

2017-09-01

Recently oxobiodegradable polyethylene gained popularity as food packaging material due to its potential to reduce polymer waste. However, this type of material can release after its oxidation off-odour compounds that affect the organoleptic properties of packaged food. Odour compounds released from both polyethylene and oxobiodegradable polyethylene before and after oxidation under a free radicals flow were investigated after 1 day, 2 days and 3 days of oxidation. The samples were analysed using headspace solid phase microextraction followed by gas chromatography-mass spectrometry and headspace solid phase microextraction coupled to gas chromatography-olfactometry-mass spectrometry. Sixty-two different odorous compounds were identified. 4-methylthio-2-butanone (fruit), nonanal (fat) and 3,6-nonadienal (fat) were present in different materials before oxidation. Multiple headspace-solid phase microextraction has been used to quantify all analytes. The most abundant compound was (Z)-3-hexenyl hexanoate with a concentration range between 1.5791±0.1387µg/g and 4.8181±0.3123µg/g. Compounds such as 2-dodecenal, 2-octenal, 2-pentanol, 3-nonenal, 3,6-nonadienal, ethyl 3-methylbutanoate, ethyl octenoate, hexanone, isopropyl hexanoate, octanal were below their LOD evaluated using MS detector; however, they were detected by gas chromatography-olfactometry. The minimum LOD and LOQ were 0.011µg/g and 0.036µg/g, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

Gas flow headspace liquid phase microextraction.

PubMed

Yang, Cui; Qiu, Jinxue; Ren, Chunyan; Piao, Xiangfan; Li, Xifeng; Wu, Xue; Li, Donghao

2009-11-06

There is a trend towards the use of enrichment techniques such as microextraction in the analysis of trace chemicals. Based on the theory of ideal gases, theory of gas chromatography and the original headspace liquid phase microextraction (HS-LPME) technique, a simple gas flow headspace liquid phase microextraction (GF-HS-LPME) technique has been developed, where the extracting gas phase volume is increased using a gas flow. The system is an open system, where an inert gas containing the target compounds flows continuously through a special gas outlet channel (D=1.8mm), and the target compounds are trapped on a solvent microdrop (2.4 microL) hanging on the microsyringe tip, as a result, a high enrichment factor is obtained. The parameters affecting the enrichment factor, such as the gas flow rate, the position of the microdrop, the diameter of the gas outlet channel, the temperatures of the extracting solvent and of the sample, and the extraction time, were systematically optimized for four types of polycyclic aromatic hydrocarbons. The results were compared with results obtained from HS-LPME. Under the optimized conditions (where the extraction time and the volume of the extracting sample vial were fixed at 20min and 10mL, respectively), detection limits (S/N=3) were approximately a factor of 4 lower than those for the original HS-LPME technique. The method was validated by comparison of the GF-HS-LPME and HS-LPME techniques using data for PAHs from environmental sediment samples.

Novel capsule phase microextraction in combination with liquid chromatography-tandem mass spectrometry for determining personal care products in environmental water.

PubMed

Lakade, Sameer S; Borrull, Francesc; Furton, Kenneth G; Kabir, Abuzar; Marcé, Rosa Maria; Fontanals, Núria

2018-05-01

A novel sample preparation technique named capsule phase microextraction (CPME) is presented here. The technique utilizes a miniaturized microextraction capsule (MEC) as the extraction medium. The MEC consists of two conjoined porous tubular polypropylene membranes, one of which encapsulates the sorbent through sol-gel technology, while the other encapsulates a magnetic metal rod. As such, MEC integrates both the extraction and stirring mechanisms into a single device. The aim of this article is to demonstrate the application potential of CPME as sample preparation technique for the extraction of a group of personal care products (PCPs) from water matrices. Among the different sol-gel sorbent materials (UCON ® , poly(caprolactone-dimethylsiloxane-caprolactone) (PCAP-DMS-CAP) and Carbowax 20M (CW-20M)) evaluated, CW-20M MEC demonstrated the best extraction performance for the selected PCPs. The extraction conditions for sol-gel CW-20M MEC were optimized, including sample pH, stirring speed, addition of salt, extraction time, sample volume, liquid desorption solvent, and time. Under the optimal conditions, sol-gel CW-20M MEC provided recoveries, ranging between 47 and 90% for all analytes, except for ethylparaben, which showed a recovery of 26%. The method based on CPME with sol-gel CW-20M followed by liquid chromatography-tandem mass spectrometry was developed and validated for the extraction of PCPs from river water and effluent wastewater samples. When analyzing different environmental samples, some analytes such as 2,4-dihydroxybenzophenone, 2,2-dihydroxy-4-4 methoxybenzophenone and 3-benzophenone were found at low ng L -1 .

Drop-to-drop solvent microextraction coupled with gas chromatography/mass spectrometry for rapid determination of trimeprazine in urine and blood of rats: application to pharmacokinetic studies.

PubMed

Agrawal, Kavita; Wu, Hui-Fen

2007-01-01

A simple and rapid method based on drop-to-drop solvent microextraction (DDSME) coupled with gas chromatography/mass spectrometry (GC/MS) has been successfully applied for the pharmacokinetic studies of trimeprazine in 8 microL of urine and blood samples of rats. Several factors that influenced the extraction efficiency of DDSME, such as selection of organic solvent, extraction time, exposure volume of organic phase, addition of salt and pH, were optimized. Linearity was obtained over the concentration ranges of 0.2-10, 0.25-7.0 and 0.5-6.0 microg/mL with correlation coefficients of 0.998, 0.996 and 0.993 in deionized water, urine and blood samples of rats, respectively. The limits of detection (LODs) of trimeprazine were 0.05, 0.06 and 0.1 microg/mL in deionized water, urine and blood samples. The concentrations of trimeprazine obtained in urine and blood samples of rats were 0.21-1.25 and 2.72-0.22 microg/mL, respectively, after a single intravenous administration of this drug. The enrichment factors and LOD values obtained by DDSME coupled to GC/MS were compared with those of hollow fiber liquid-phase microextraction (HF-LPME) combined with GC/MS. We believe that this novel approach can be very useful in clinical application since only one microdrop of biological samples was required to perform the pharmacokinetic studies from rats, so the sample pretreatments for animal experiments can be very easy too. Copyright (c) 2007 John Wiley & Sons, Ltd.

Solid-phase microextraction followed by gas chromatography-mass spectrometry for the determination of ink photo-initiators in packed milk.

PubMed

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

2010-06-30

A novel, single step method for the determination of seven ink photo-initiators in carton packed milk samples is described. Solid-phase microextraction (SPME) and gas chromatography (GC), combined with mass spectrometry (MS), were used as sample preparation and determination techniques, respectively. Parameters affecting the performance of the microextraction process were thoroughly evaluated using uni- and multivariate optimization strategies, based on the use of experimental factorial designs. The coating of the SPME fibre, together with the sampling mode and the temperature were the factors playing a major influence on the efficiency of the extraction. Under final conditions, 1.5 mL of milk and 8.5 mL of ultrapure water were poured in a glass vessel, which was closed and immersed in a water boiling bath. A poly(dimethylsiloxane)-divinylbenzene (PDMS-DVB) coated fibre was exposed directly to the diluted sample for 40 min. After that, the fibre was desorbed in the injector of the GC-MS system for 3 min. The optimized method provided limits of quantification (LOQs) between 0.2 and 1 microg L(-1) and a good linearity in the range between 1 and 250 microg L(-1). The inter-day precision remained below 15% for all compounds in spiked whole milk. The efficiency of the extraction changed for whole, semi-skimmed and skimmed milk; however, no differences were noticed among the relative recoveries achieved for milk samples, from different brands, with the same fat content. Copyright 2010 Elsevier B.V. All rights reserved.

Dispersive microextraction based on water-coated Fe₃O₄ followed by gas chromatography-mass spectrometry for determination of 3-monochloropropane-1,2-diol in edible oils.

PubMed

Zhao, Qin; Wei, Fang; Xiao, Neng; Yu, Qiong-Wei; Yuan, Bi-Feng; Feng, Yu-Qi

2012-06-01

In the present work, we developed a novel dispersive microextraction technique by combining the advantages of liquid-phase microextraction (LPME) and magnetic solid-phase extraction (MSPE). In this method, trace amount of water directly absorbed on bare Fe₃O₄ to form water-coated Fe₃O₄ (W-Fe₃O₄) and rapid extraction can be achieved while W-Fe₃O₄ dispersed in the sample solution. The analyte adsorbed W-Fe₃O₄ can be easily collected and isolated from sample solution by application of a magnet. It was worth noting that in the proposed method water was used as extractant and Fe₃O₄ served as the supporter and retriever of water. The performance of the method was evaluated by extraction of 3-monochloropropane-1,2-diol (3-MCPD) from edible oils. The extracted 3-MCPD was then derived by a silylanization reagent (1-trimethylsilylimidazole) before gas chromatography-mass spectrometry (GC-MS) analysis. Several parameters that affected the extraction and derivatization efficiency were investigated. Our results showed that the limit of detection for 3-MCPD was 1.1 ng/g. The recoveries in spiked oil samples were in the range of 70.0-104.9% with the RSDs less than 5.6% (intra-day) and 6.4% (inter-day). Taken together, the simple, rapid and cost-effective method developed in current study, offers a potential application for the extraction and preconcentration of hydrophilic analytes from complex fatty samples. Copyright © 2012 Elsevier B.V. All rights reserved.

Accurate determination of 3-alkyl-2-methoxypyrazines in wines by gas chromatography quadrupole time-of-flight tandem mass spectrometry following solid-phase extraction and dispersive liquid-liquid microextraction.

PubMed

Fontana, Ariel; Rodríguez, Isaac; Cela, Rafael

2017-09-15

A new reliable method for the determination 3-alkyl-2-methoxypyrazines (MPs) in wine samples based on the sequential combination of solid-phase extraction (SPE), dispersive liquid-liquid microextraction (DLLME) and gas chromatography (GC) quadrupole time-of-flight accurate tandem mass spectrometry (QTOF-MS/MS) is presented. Primary extraction of target analytes was carried out by using a reversed-phase Oasis HLB (200mg) SPE cartridge combined with acetonitrile as elution solvent. Afterwards, the SPE extract was submitted to DLLME concentration using 0.06mL carbon tetrachloride (CCl 4 ) as extractant. Under final working conditions, sample concentration factors above 379 times and limits of quantification (LOQs) between 0.3 and 2.1ngL -1 were achieved. Moreover, the overall extraction efficiency of the method was unaffected by the particular characteristics of each wine; thus, accurate results (relative recoveries from 84 to 108% for samples spiked at concentrations from 5 to 25ngL -1 ) were obtained using matrix-matched standards, without using standard additions over every sample. Highly selective chromatographic records were achieved considering a mass window of 5mDa, centered in the quantification product ion corresponding to each compound. Twelve commercial wines, elaborated with grapes from different varieties and geographical origins, were processed with the optimized method. The 2-isobutyl-3-methoxypyrazine (IBMP) was determined at levels above the LOQs of the method in half of the samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Metal-organic frameworks for analytical chemistry: from sample collection to chromatographic separation.

PubMed

Gu, Zhi-Yuan; Yang, Cheng-Xiong; Chang, Na; Yan, Xiu-Ping

2012-05-15

In modern analytical chemistry researchers pursue novel materials to meet analytical challenges such as improvements in sensitivity, selectivity, and detection limit. Metal-organic frameworks (MOFs) are an emerging class of microporous materials, and their unusual properties such as high surface area, good thermal stability, uniform structured nanoscale cavities, and the availability of in-pore functionality and outer-surface modification are attractive for diverse analytical applications. This Account summarizes our research on the analytical applications of MOFs ranging from sampling to chromatographic separation. MOFs have been either directly used or engineered to meet the demands of various analytical applications. Bulk MOFs with microsized crystals are convenient sorbents for direct application to in-field sampling and solid-phase extraction. Quartz tubes packed with MOF-5 have shown excellent stability, adsorption efficiency, and reproducibility for in-field sampling and trapping of atmospheric formaldehyde. The 2D copper(II) isonicotinate packed microcolumn has demonstrated large enhancement factors and good shape- and size-selectivity when applied to on-line solid-phase extraction of polycyclic aromatic hydrocarbons in water samples. We have explored the molecular sieving effect of MOFs for the efficient enrichment of peptides with simultaneous exclusion of proteins from biological fluids. These results show promise for the future of MOFs in peptidomics research. Moreover, nanosized MOFs and engineered thin films of MOFs are promising materials as novel coatings for solid-phase microextraction. We have developed an in situ hydrothermal growth approach to fabricate thin films of MOF-199 on etched stainless steel wire for solid-phase microextraction of volatile benzene homologues with large enhancement factors and wide linearity. Their high thermal stability and easy-to-engineer nanocrystals make MOFs attractive as new stationary phases to fabricate MOF-coated capillaries for high-resolution gas chromatography (GC). We have explored a dynamic coating approach to fabricate a MOF-coated capillary for the GC separation of important raw chemicals and persistent organic pollutants with high resolution and excellent selectivity. We have combined a MOF-coated fiber for solid-phase microextraction with a MOF-coated capillary for GC separation, which provides an effective MOF-based tandem molecular sieve platform for selective microextraction and high-resolution GC separation of target analytes in complex samples. Microsized MOFs with good solvent stability are attractive stationary phases for high-performance liquid chromatography (HPLC). These materials have shown high resolution and good selectivity and reproducibility in both the normal-phase HPLC separation of fullerenes and substituted aromatics on MIL-101 packed columns and position isomers on a MIL-53(Al) packed column and the reversed-phase HPLC separation of a wide range of analytes from nonpolar to polar and acidic to basic solutes. Despite the above achievements, further exploration of MOFs in analytical chemistry is needed. Especially, analytical application-oriented engineering of MOFs is imperative for specific applications.

Determination of bisphenol A in thermal printing papers treated by alkaline aqueous solution using the combination of single-drop microextraction and HPLC.

PubMed

Gao, Leihong; Zou, Jing; Liu, Haihong; Zeng, Jingbin; Wang, Yiru; Chen, Xi

2013-04-01

A method for the quantitative determination of bisphenol A in thermal printing paper was developed and validated. Bisphenol A was extracted from the paper samples using 2% NaOH solution, then the extracted analyte was enriched using single-drop microextraction followed by HPLC analysis. Several parameters relating to the single-drop microextraction efficiency including extraction solvent, extraction temperature and time, stirring rate, and pH of donor phase were studied and optimized. Spiked recovery of bisphenol A at 20 and 5 mg/g was found to be 95.8 and 108%, and the method detection limit and method quantification limit was 0.03 and 0.01 mg/g, respectively. Under the optimized conditions, the proposed method was applied to the determination of bisphenol A in seven types of thermal printing paper samples, and the concentration of bisphenol A was found in the range of 0.53-20.9 mg/g. The considerably minimum usage of organic solvents (5 μL 1-octanol) and high enrichment factor (189-197) in the sample preparation are the two highlighted advantages in comparison with previously published works. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Study of the aroma formation and transformation during the manufacturing process of oolong tea by solid-phase micro-extraction and gas chromatography-mass spectrometry combined with chemometrics.

PubMed

Ma, Chengying; Li, Junxing; Chen, Wei; Wang, Wenwen; Qi, Dandan; Pang, Shi; Miao, Aiqing

2018-06-01

Oolong tea is a typical semi-fermented tea and is famous for its unique aroma. The aim of this study was to compare the volatile compounds during manufacturing process to reveal the formation of aroma. In this paper, a method was developed based on head-space solid phase microextraction/gas chromatography-mass spectrometry (HS-SPME/GC-MS) combined with chemometrics to assess volatile profiles during manufacturing process (fresh leaves, sun-withered leaves, rocked leaves and leaves after de-enzyming). A total of 24 aroma compounds showing significant differences during manufacturing process were identified. Subsequently, according to these aroma compounds, principal component analysis and hierarchical cluster analysis showed that the four samples were clearly distinguished from each other, which suggested that the 24 identified volatile compounds can represent the changes of volatile compounds during the four steps. Additionally, sun-withering, rocking and de-enzyming can influence the variations of volatile compounds in different degree, and we found the changes of volatile compounds in withering step were less than other two manufacturing process, indicating that the characteristic volatile compounds of oolong tea might be mainly formed in rocking stage by biological reactions and de-enzyming stage through thermal chemical transformations rather than withering stage. This study suggested that HS-SPME/GC-MS combined with chemometrics methods is accurate, sensitive, fast and ideal for rapid routine analysis of the aroma compounds changes in oolong teas during manufacturing processing. Copyright © 2018 Elsevier Ltd. All rights reserved.

Field and Laboratory Application of a Gas Chromatograph Low Thermal Mass Resistively Heated Column System in Detecting Traditional and Non-Traditional Chemical Warfare Agents Using Solid Phase Micro-Extraction

DTIC Science & Technology

2005-02-01

followed by extensive sample preparation procedures that are performed in a laboratory. Analysis is typically conducted by injecting a liquid or gas sample...Alfentanil, Remifentanil , Sufentanil, and Carfentanil) in a laboratory. (5) Quantitatively determine a maximum temperature ramping rate at which the LTM...RHT Column combined with a GC-MS can separate and analyze a mixture of non- traditional CWAs (i.e. Fentanyl, Alfentanil, Remifentanil , Sufentanil

Chip-based magnetic solid phase microextraction coupled with ICP-MS for the determination of Cd and Se in HepG2 cells incubated with CdSe quantum dots.

PubMed

Yu, Xiaoxiao; Chen, Beibei; He, Man; Wang, Han; Hu, Bin

2018-03-01

The quantification of trace Cd and Se in cells incubated with CdSe quantum dots (QDs) is critical to investigate the cytotoxicity of CdSe QDs. In this work, a miniaturized platform, namely chip-based magnetic solid phase microextraction (MSPME) packing with sulfhydryl group functionalized magnetic nanoparticles, was fabricated and combined with inductively coupled plasma mass spectrometry (ICP-MS) for the determination of trace Cd and Se in cells. Under the optimized conditions, the limits of detection (LOD) of the developed chip-based MSPME-ICP-MS system are 2.2 and 21ngL -1 for Cd and Se, respectively. The proposed method is applied successfully to the analysis of total and released small molecular fraction of Cd and Se in Human hepatocellular carcinoma cells (HepG2 cells) incubated with CdSe QDs, and the recoveries for the spiked samples are in the range of 86.0-109%. This method shows great promise to analyze cell samples and the obtained results are instructive to explore the cytotoxicity mechanism of CdSe QDs in cells. Copyright © 2017 Elsevier B.V. All rights reserved.

A fast and simple solid phase microextraction coupled with gas chromatography-triple quadrupole mass spectrometry method for the assay of urinary markers of glutaric acidemias.

PubMed

Naccarato, Attilio; Gionfriddo, Emanuela; Elliani, Rosangela; Sindona, Giovanni; Tagarelli, Antonio

2014-10-30

The analysis of characteristic urinary acidic markers such as glutaric, 3-hydroxyglutaric, 2-hydroxyglutaric, adipic, suberic, sebacic, ethylmalonic, 3-hydroxyisovaleric and isobutyric acid constitutes the recommended follow-up testing procedure for glutaric acidemia type 1 (GA-1) and type 2 (GA-2). The goal of the work herein presented is the development of a fast and simple method for the quantification of these biomarkers in human urine. The proposed analytical approach is based on the use of solid phase microextraction (SPME) combined with gas chromatography-triple quadrupole mass spectrometry (GC-QqQ-MS) afterward a rapid derivatization of acidic moieties by propyl chloroformate, propanol and pyridine. Trueness and precision of the proposed protocol, tested at 5, 30 and 80mgl -1 , provided satisfactory values: recoveries were in the range between 72% and 116% and the relative standard deviations (RSD%) were between 0.9% and 18% (except for isobutyric acid at 5mgl -1 ). The LOD values achieved by the proposed method ranged between 1.0 and 473μgl -1 . Copyright © 2014 Elsevier B.V. All rights reserved.

Determination of desipramine in biological samples using liquid-liquid-liquid microextraction combined with in-syringe derivatization, gas chromatography, and nitrogen/phosphorus detection.

PubMed

Saraji, Mohammad; Mehrafza, Narges; Bidgoli, Ali Akbar Hajialiakbari; Jafari, Mohammad Taghi

2012-10-01

A method was established for the determination of desipramine in biological samples using liquid-liquid-liquid microextraction followed by in-syringe derivatization and gas chromatography-nitrogen phosphorus detection. The extraction method was based on the use of two immiscible organic solvents. n-Dodecane was impregnated in the pores of the hollow fiber and methanol was placed inside the lumen of the fiber as the acceptor phase. Acetic anhydride was used as the reagent for the derivatization of the analyte inside the syringe barrel. Parameters that affect the extraction efficiency (composition of donor and acceptor phase, ionic strength, sample temperature, and extraction time) as well as derivatization efficiency (amount of acetic anhydride and reaction time and temperature) were investigated. The limit of detection was 0.02 μg/L with intra and interday RSDs of 2.6 and 7.7%, respectively. The linearity of the method was in the range of 0.2-20 μg/L (r(2) = 0.9986). The method was successfully applied to determine desipramine in human plasma and urine. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimization of dispersive liquid-phase microextraction based on solidified floating organic drop combined with high-performance liquid chromatography for the analysis of glucocorticoid residues in food.

PubMed

Huang, Yuan; Zheng, Zhiqun; Huang, Liying; Yao, Hong; Wu, Xiao Shan; Li, Shaoguang; Lin, Dandan

2017-05-10

A rapid, simple, cost-effective dispersive liquid-phase microextraction based on solidified floating organic drop (SFOD-LPME) was developed in this study. Along with high-performance liquid chromatography, we used the developed approach to determine and enrich trace amounts of four glucocorticoids, namely, prednisone, betamethasone, dexamethasone, and cortisone acetate, in animal-derived food. We also investigated and optimized several important parameters that influenced the extraction efficiency of SFOD-LPME. These parameters include the extractant species, volumes of extraction and dispersant solvents, sodium chloride addition, sample pH, extraction time and temperature, and stirring rate. Under optimum experimental conditions, the calibration graph exhibited linearity over the range of 1.2-200.0ng/ml for the four analytes, with a reasonable linearity(r 2 : 0.9990-0.9999). The enrichment factor was 142-276, and the detection limits was 0.39-0.46ng/ml (0.078-0.23μg/kg). This method was successfully applied to analyze actual food samples, and good spiked recoveries of over 81.5%-114.3% were obtained. Copyright © 2017. Published by Elsevier B.V.

Ionic liquid polymer functionalized carbon nanotubes-doped poly(3,4-ethylenedioxythiophene) for highly-efficient solid-phase microextraction of carbamate pesticides.

PubMed

Wu, Mian; Wang, Liying; Zeng, Baizhao; Zhao, Faqiong

2016-04-29

A poly(3,4-ethylenedioxythiophene)-ionic liquid polymer functionalized multiwalled carbon nanotubes (PEDOT-PIL/MWCNTs) composite solid-phase microextraction (SPME) coating was fabricated by electrodeposition. After being dipped in Nafion solution, a Nafion-modified coating was obtained. The outer layer Nafion played a crucial role in enhancing the durability and stability of the coating, thus it was robust enough for replicated extraction for at least 150 times without decrease of extraction performance. The Nafion-modified coating exhibited much higher sensitivity than commercial coatings for the direct extraction of carbamate pesticides in aqueous solutions, due to its strong hydrophobic effect and π-π affinity based enrichment. When it was used for the determination of carbamate pesticides in combination with gas chromatography-flame ionization detection, good linearity (correlation coefficients higher than 0.9981), low limits of detection (15.2-27.2 ng/L) and satisfactory precision (relative standard deviation <8.2%, n=5) were achieved. The developed method was applied to the analysis of four carbamate pesticides in apple and lettuce samples, and acceptable recoveries (i.e. 87.5-106.5%) were obtained for the standard addition. Copyright © 2016 Elsevier B.V. All rights reserved.

Development of a novel naphthoic acid ionic liquid and its application in "no-organic solvent microextraction" for determination of triclosan and methyltriclosan in human fluids and the method optimization by central composite design.

PubMed

Wang, Hui; Gao, Jiajia; Yu, Nana; Qu, Jingang; Fang, Fang; Wang, Huili; Wang, Mei; Wang, Xuedong

2016-07-01

In traditional ionic liquids (ILs)-based microextraction, the hydrophobic and hydrophilic ILs are often used as extractant and disperser, respectively. However, the functional effects of ILs are not utilized in microextraction procedures. Herein, we introduced 1-naphthoic acid into imidazolium ring to synthesize a novel ionic liquid 1-butyl-3-methylimidazolium naphthoic acid salt ([C4MIM][NPA]), and its structure was characterized by IR, (1)H NMR and MS. On the basis of its acidic property and lower solubility than common [CnMIM][BF4], it was used as a mixing dispersive solvent with [C4MIM][BF4] in "functionalized ionic liquid-based no organic solvent microextraction (FIL-NOSM)". Utilization of [C4MIM][NPA] in FIL-NOSM procedures has two obvious advantages: (1) it promoted the non-polar environment, increased volume of the sedimented phase, and thus could enhance the extraction recoveries of triclosan (TCS) and methyltriclosan (MTCS) by more than 10%; and (2) because of the acidic property, it can act as a pH modifier, avoiding extra pH adjustment step. By combining single factor optimization and central composite design, the main factors in the FIL-NOSM method were optimized. Under the optimal conditions, the relative recoveries of TCS and MTCS reached up to 98.60-106.09%, and the LODs of them were as low as 0.12-0.15µgL(-1) in plasma and urine samples. In total, this [C4MIM][NPA]-based FIL-NOSM method provided high extraction efficiency, and required less pretreatment time and unutilized any organic solvent. To the best of our knowledge, this is the first application of [C4mim][NPA]-based microextraction method for the simultaneous quantification of trace TCS and MTCS in human fluids. Copyright © 2016 Elsevier B.V. All rights reserved.

Improved chip design for integrated solid-phase microextraction in on-line proteomic sample preparation.

PubMed

Bergkvist, Jonas; Ekström, Simon; Wallman, Lars; Löfgren, Mikael; Marko-Varga, György; Nilsson, Johan; Laurell, Thomas

2002-04-01

A recently introduced silicon microextraction chip (SMEC), used for on-line proteomic sample preparation, has proved to facilitate the process of protein identification by sample clean up and enrichment of peptides. It is demonstrated that a novel grid-SMEC design improves the operating characteristics for solid-phase microextraction, by reducing dispersion effects and thereby improving the sample preparation conditions. The structures investigated in this paper are treated both numerically and experimentally. The numerical approach is based on finite element analysis of the microfluidic flow in the microchip. The analysis is accomplished by use of the computational fluid dynamics-module FLOTRAN in the ANSYS software package. The modeling and analysis of the previously reported weir-SMEC design indicates some severe drawbacks, that can be reduced by changing the microextraction chip geometry to the grid-SMEC design. The overall analytical performance was thereby improved and also verified by experimental work. Matrix-assisted laser desorption/ionization mass spectra of model peptides extracted from both the weir-SMEC and the new grid-SMEC support the numerical analysis results. Further use of numerical modeling and analysis of the SMEC structures is also discussed and suggested in this work.

Hollow-Fibre-Supported Dispersive Liquid-Liquid Microextraction for Determination of Atrazine and Triclosan in Aqueous Samples

PubMed Central

Letseka, Thabiso

2017-01-01

We report the application of the dispersive liquid-liquid microextraction coupled to hollow-fibre membrane-assisted liquid-phase microextraction and its application for extraction of atrazine and triclosan. Under optimum conditions, namely, 25 μL of a 1 : 4 chlorobenzene : ethyl acetate mixture dispersed in 1 mL of aqueous sample, 10% (m/v) NaCl, a magnetic stirrer speed at 600 rpm, and 10 minutes' extraction time with toluene-filled fibre as the acceptor phase, the method demonstrates sufficient figures of merit. These include linearity (R2 ≥ 0.9975), intravial precision (%RSD ≤ 7.6), enrichment factors (127 and 142), limits of detection (0.0081 and 0.0169 µg/mL), and recovery from river water and sewerage (96–101%). The relatively high detection limits are attributed to the flame ionization detector which is less preferred than a mass spectrometer in trace analyses. This is the first report of a homogenous mixture of the dispersed organic solvent in aqueous solutions and its employment in extraction of organic compounds from aqueous solutions. It therefore adds yet another candidate in the pool of miniaturised solvent microextraction techniques. PMID:29158736

A star-shaped polythiophene dendrimer coating for solid-phase microextraction of triazole agrochemicals.

PubMed

Abolghasemi, Mir Mahdi; Habibiyan, Rahim; Jaymand, Mehdi; Piryaei, Marzieh

2018-02-14

A nanostructured star-shaped polythiophene dendrimer was prepared and used as a fiber coating for headspace solid phase microextraction of selected triazolic pesticides (tebuconazole, hexaconazole, penconazole, diniconazole, difenoconazole, triticonazole) from water samples. The dendrimer with its large surface area was characterized by thermogravimetric analysis, UV-Vis spectroscopy and field emission scanning electron microscopy. It was placed on a stainless steel wire for use in SPME. The experimental conditions for fiber coating, extraction, stirring rate, ionic strength, pH value, desorption temperature and time were optimized. Following thermal desorption, the pesticides were quantified by GC-MS. Under optimum conditions, the repeatability (RSD) for one fiber (for n = 3) ranges from 4.3 to 5.6%. The detection limits are between 8 and 12 pg mL -1 . The method is fast, inexpensive (in terms of equipment), and the fiber has high thermal stability. Graphical abstract Schematic presentation of a nanostructured star-shaped polythiophene dendrimer for use in headspace solid phase microextraction of the triazolic pesticides (tebuconazole, hexaconazole, penconazole, diniconazole, difenoconazole, triticonazole). They were then quantified by gas chromatography-mass spectrometry.

A chemometric strategy for optimization of solid-phase microextraction: determination of bisphenol A and 4-nonylphenol with HPLC.

PubMed

Liu, Xiaoyan; Zhang, Xiaoyun; Zhang, Haixia; Liu, Mancang

2008-08-01

A sensitive method for the analysis of bisphenol A and 4-nonylphenol is developed by means of the optimization of solid-phase microextraction using Uniform Experimental Design methodology followed by high-performance liquid chromatographic analysis with fluorescence detection. The optimal extraction conditions are determined based on the relationship between parameters and the peak area. The curve calibration plots are linear (r2>or=0.9980) over the concentration range of 1.25-125 ng/mL for bisphenol A and 2.59-202.96 ng/mL for 4-nonylphenol, respectively. The detection limits, based on a signal-to-noise ratio of 3, are 0.097 ng/mL for bisphenol A and 0.27 ng/mL for 4-nonylphenol, respectively. The validity of the proposed method is demonstrated by the analysis of the investigated analytes in real water samples and sensitivity of the optimized method is verified by comparing results with those obtained by previous methods using the same commercial solid-phase microextraction fiber.

Sample preparation techniques for the determination of trace residues and contaminants in foods.

PubMed

Ridgway, Kathy; Lalljie, Sam P D; Smith, Roger M

2007-06-15

The determination of trace residues and contaminants in complex matrices, such as food, often requires extensive sample extraction and preparation prior to instrumental analysis. Sample preparation is often the bottleneck in analysis and there is a need to minimise the number of steps to reduce both time and sources of error. There is also a move towards more environmentally friendly techniques, which use less solvent and smaller sample sizes. Smaller sample size becomes important when dealing with real life problems, such as consumer complaints and alleged chemical contamination. Optimal sample preparation can reduce analysis time, sources of error, enhance sensitivity and enable unequivocal identification, confirmation and quantification. This review considers all aspects of sample preparation, covering general extraction techniques, such as Soxhlet and pressurised liquid extraction, microextraction techniques such as liquid phase microextraction (LPME) and more selective techniques, such as solid phase extraction (SPE), solid phase microextraction (SPME) and stir bar sorptive extraction (SBSE). The applicability of each technique in food analysis, particularly for the determination of trace organic contaminants in foods is discussed.

Pseudo-stir bar hollow fiber solid/liquid phase microextraction combined with anodic stripping voltammetry for determination of lead and cadmium in water samples

PubMed Central

Es’haghi, Zarrin; Hoseini, Hasan Ali; Mohammadi-Nokhandani, Saeed; Ebrahimi, Javad

2013-01-01

A new procedure is presented for the determination of low concentrations of lead and cadmium in water samples. Ligand assisted pseudo-stir bar hollow fiber solid/liquid phase microextraction using sol–gel sorbent reinforced with carbon nanotubes was combined with differential pulse anodic stripping voltammetry for simultaneous determination of cadmium and lead in tap water, and Darongar river water samples. In the present work, differential pulse anodic stripping voltammetry (DPASV) using a hanging mercury drop electrode (HMDE) was used in order to determine the ultra trace level of lead and cadmium ions in real samples. This method is based on accumulation of lead and cadmium ions on the electrode using different ligands; Quinolin-8-ol, 5,7-diiodo quinoline-8-ol, 4,5-diphenyl-1H-imidazole-2(3H)-one and 2-{[2-(2-Hydroxy-ethylamino)-ethylamino]-methyl}-phenol as the complexing agent. The optimized conditions were obtained. The relationship between the peak current versus concentration was linear over the range of 0.05–500 ng mL−1 for Cd (II) and Pb (II). The limits of detection for lead and cadmium were 0.015 ng mL−1 and 0.012 ng mL−1, respectively. Under the optimized conditions, the pre-concentration factors are 2440 and 3710 for Cd (II) and Pb (II) in 5 mL of water sample, respectively. PMID:25685537

Optimization of headspace solid phase microextraction based on nano-structured ZnO combined with gas chromatography-mass spectrometry for preconcentration and determination of ultra-traces of chlorobenzenes in environmental samples.

PubMed

Ghasemi, Ensieh; Sillanpää, Mika

2014-12-01

In this study, a simple, novel and efficient preconcentration method for the determination of some chlorobenzenes (monochlorobenzene (MCB), three isomeric forms of dichlorobenzene (diCB), 1,3,5-trichlorobenzene (triCB) and hexachlorobenze (hexaCB)) has been developed using a headspace solid phase microextraction (HS-SPME) based on nano-structured ZnO combined with capillary gas chromatography-mass spectrometry (GC-MS). ZnO nanorods have been grown on fused silica fibers using a hydrothermal process. The diameter of ZnO nanorods was in the range of 50-80 nm. The effect of different variables on the extraction efficiency was studied simultaneously using an experimental design. The variables of interest in the HS-SPME were stirring rate, desorption time and temperature, ionic strength, extraction time and temperature. For this purpose, a multivariate strategy was applied based on an experimental design using a Plackett-Burman design for screening and a Box-Behnken design for optimizing of the significant factors. The detection limit and relative standard deviation (RSD) (n=5) for the target analytes were in the range of 0.01-0.1 ng L(-1) and 4.3-7.6%, respectively. The developed technique was found to be successfully applicable to preconcentration and determination of the target analytes in environmental water and soil samples. Copyright © 2014 Elsevier B.V. All rights reserved.

Automated dynamic hollow fiber liquid-liquid-liquid microextraction combined with capillary electrophoresis for speciation of mercury in biological and environmental samples.

PubMed

Li, Pingjing; He, Man; Chen, Beibei; Hu, Bin

2015-10-09

A simple home-made automatic dynamic hollow fiber based liquid-liquid-liquid microextraction (AD-HF-LLLME) device was designed and constructed for the simultaneous extraction of organomercury and inorganic mercury species with the assistant of a programmable flow injection analyzer. With 18-crown-6 as the complexing reagent, mercury species including methyl-, ethyl-, phenyl- and inorganic mercury were extracted into the organic phase (chlorobenzene), and then back-extracted into the acceptor phase of 0.1% (m/v) 3-mercapto-1-propanesulfonic acid (MPS) aqueous solution. Compared with automatic static (AS)-HF-LLLME system, the extraction equilibrium of target mercury species was obtained in shorter time with higher extraction efficiency in AD-HF-LLLME system. Based on it, a new method of AD-HF-LLLME coupled with large volume sample stacking (LVSS)-capillary electrophoresis (CE)/UV detection was developed for the simultaneous analysis of methyl-, phenyl- and inorganic mercury species in biological samples and environmental water. Under the optimized conditions, AD-HF-LLLME provided high enrichment factors (EFs) of 149-253-fold within relatively short extraction equilibrium time (25min) and good precision with RSD between 3.8 and 8.1%. By combining AD-HF-LLLME with LVSS-CE/UV, EFs were magnified up to 2195-fold and the limits of detection (at S/N=3) for target mercury species were improved to be sub ppb level. Copyright © 2015 Elsevier B.V. All rights reserved.

Determination of metal ions in tea samples using task-specific ionic liquid-based ultrasound-assisted dispersive liquid-liquid microextraction coupled to liquid chromatography with ultraviolet detection.

PubMed

Werner, Justyna

2016-04-01

Task-specific ionic liquid-based ultrasound-assisted dispersive liquid-liquid microextraction was used for the preconcentration of cadmium(II), cobalt(II), and lead(II) ions in tea samples, which were subsequently analyzed by liquid chromatography with UV detection. The proposed method of preconcentration is free of volatile organic compounds, which are often used as extractants and dispersing solvents in classic techniques of microextraction. A task-specific ionic liquid trioctylmethylammonium thiosalicylate was used as an extractant and a chelating agent. Ultrasound was used to disperse the ionic liquid. After microextraction, the phases were separated by centrifugation, and the ionic liquid phase was solubilized in methanol and directly injected into the liquid chromatograph. Selected microextraction parameters, such as the volume of ionic liquid, the pH of the sample, the duration of ultrasound treatment, the speed and time of centrifugation, and the effect of ionic strength, were optimized. Under optimal conditions an enrichment factor of 200 was obtained for each analyte. The limits of detection were 0.002 mg/kg for Cd(II), 0.009 mg/kg for Co(II), and 0.013 mg/kg for Pb(II). The accuracy of the proposed method was evaluated by an analysis of the Certified Reference Materials (INCT-TL-1, INCT-MPH-2) with the recovery values in the range of 90-104%. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Capillary liquid chromatography combined with pressurized liquid extraction and dispersive liquid-liquid microextraction for the determination of vitamin E in cosmetic products.

PubMed

Viñas, Pilar; Pastor-Belda, Marta; Campillo, Natalia; Bravo-Bravo, María; Hernández-Córdoba, Manuel

2014-06-01

Capillary liquid chromatography (LC) is used for the determination of tocopherols and tocotrienols in cosmetic products. Dispersive liquid-liquid microextraction (DLLME) allows the analytes to be preconcentrated into a very small volume of organic solvent which is then injected into the chromatograph running at a very low flow rate. Pressurized liquid extraction (PLE) at a high temperature and pressure was used to isolate vitamin E forms from cosmetics. The Taguchi experimental method was used to optimize the factors affecting DLLME. The parameters selected were 2mL of acetonitrile (disperser solvent), 100μL carbon tetrachloride (extraction solvent) and 10mL aqueous solution. A volume of 5μL of the organic phase was injected into the reversed-phase capillary LC system equipped with a diode array detector and using an isocratic mobile phase composed of an 95:5 (v/v) methanol:water mixture at a flow-rate of 20μLmin(-1). Quantification was carried out using aqueous standards and detection limits were in the range 0.1-0.5ngmL(-1), corresponding to 3-15ngg(-1) in the cosmetic sample. The recoveries were in the 87-105% range, with RSDs lower than 7.8%. The method was validated according to international guidelines and using a certified reference material. Copyright © 2014 Elsevier B.V. All rights reserved.

Analysis of PBDEs in soil, dust, spiked lake water, and human serum samples by hollow fiber-liquid phase microextraction combined with GC-ICP-MS.

PubMed

Xiao, Qin; Hu, Bin; Duan, Jiankun; He, Man; Zu, Wanqing

2007-10-01

A novel method for the analysis of four polybrominated diphenyl ethers (PBDEs) in environmental and human serum samples based on hollow fiber-liquid phase microextraction (HF-LPME) followed by gas chromatography-inductively coupled plasma mass spectrometric (GC-ICP-MS) detection has been developed. The organic solvent in the porous hollow fiber was first dipped into the sample for extraction at a given time, and the retracted organic phase was introduced into the GC-ICP-MS for analysis. The addition of methanol has a strong effect on the HF-LPME extraction efficiency. Other significant parameters affecting the extraction efficiency of HF-LPME were also studied. HF-LPME was effective to isolate the analytes from the complex matrix. Under the optimized conditions, the detection limits of the proposed method varied from 15.2 to 40.5 ng/L. In general, the relative standard deviations (RSDs) were less than 10%. Good linearity was obtained with the correlation coefficients all better than 0.999. The proposed method is simple, quick, few microliters of organic solvent required, and is especially suitable for the analysis of the real sample with small amount available. The overall process of HF-LPME with GC-ICP-MS was applied successfully for the determination of polybrominated diphenyl ethers (PBDEs) in environmental and spiked human serum samples, and the results were satisfactory.

Head space solid phase microextraction based on nano-structured lead dioxide: application to the speciation of volatile organoselenium in environmental and biological samples.

PubMed

Ghasemi, Ensieh; Farahani, Hadi

2012-10-05

A novel and efficient speciation method based on the nano-structured lead dioxide as stationary phase of head space solid phase microextraction combined with gas chromatography mass spectrometry (GC-MS) was developed for the determination of volatile organoselenium compounds (dimethylselenide (DMSe) and dimethyldiselenide (DMDSe)) in different biological and environmental samples. PbO(2) particles with a diameter in the range of 50-70 nm have been grown on platinum wire via elechtrochemical deposition. The effect of different variables on the extraction efficiency was studied simultaneously using an experimental design. The variables of interest in the HS-SPME were condition of coating preparation, desorption time, stirring rate, desorption temperature, ionic strength, time and temperature of extraction. A Plackett-Burman design was performed for screening in order to determine the significant variables affecting the extraction efficiency. Then, the significant factors were optimized by a Box-Behnken design (BBD) and the response surface equations were derived. The detection limit and relative standard deviation (RSD) (n=5, c=50 μgL(-1)) for DMSe were 16 ngL(-1) and 4.3%, respectively. They were also obtained for DMDSe as 11ngL(-1) and 4.6%, respectively. The developed technique was found to be applicable to spiked environmental and biological samples. Copyright © 2012 Elsevier B.V. All rights reserved.

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.

Using Single Drop Microextraction for Headspace Analysis with Gas Chromatography

NASA Astrophysics Data System (ADS)

Riccio, Daniel; Wood, Derrick C.; Miller, James M.

2008-07-01

Headspace (HS) gas chromatography (GC) is commonly used to analyze samples that contain non-volatiles. In 1996, a new sampling technique called single drop microextraction, SDME, was introduced, and in 2001 it was applied to HS analysis. It is a simple technique that uses equipment normally found in the undergraduate laboratory, making it ideal for instructional use, especially to illustrate HS analysis or as an alternative to solid-phase microextraction (SPME) to which it is very similar. The basic principles and practice of HS-GC using SDME are described, including a complete review of the literature. Some possible experiments are suggested using water and N -methylpyrrolidone (NMP) as solvents.

Effect of seaweed supplementation on tocopherol concentrations in bovine milk using dispersive liquid-liquid microextraction.

PubMed

Quigley, Andrew; Walsh, Siobhán W; Hayes, Eva; Connolly, Damian; Cummins, Wayne

2018-06-07

A dispersive liquid-liquid microextraction (DLLME) method, combined with HPLC-UV detection, was developed for the extraction and preconcentration of δ-tocopherol from bovine milk. This method was used to study the effect of supplementing cow feed with the seaweed Ascophyllum nodosum on vitamin content in milk. The optimal experimental conditions were determined: 200 μL of chloroform (extraction solvent), 1.0 mL of ethanol (dispersive solvent), 5 mL of water (aqueous phase). Under these optimal conditions the DLLME method provided linearity in the range 0.01 μg/mL to 8 μg/mL with R 2 values of 0.998. Limit of detection (LOD) was 0.01 μg/mL, while the enrichment factor was 89. Cow feed that was supplemented with Ascophyllum nodosum was shown to increase δ-tocopherol levels from 3.82 μg/mL to 5.96 μg/mL. Copyright © 2018. Published by Elsevier B.V.

Global volatile profile of virgin olive oils flavoured by aromatic/medicinal plants.

PubMed

Perestrelo, R; Silva, C; Silva, P; Câmara, J S

2017-07-15

The global volatile profile of commercial virgin olive oils and flavoured olive oils with aromatic/medicinal plants, was established using liquid-liquid microextraction (LLME) and headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-quadrupole mass spectrometry (GC-qMS). More than 60 volatile organic compounds (VOCs belonging to different groups were identified using both methods. Olive oils volatile profile was slightly influenced by maceration process, which occurred at room temperature (20±2°C) for 15days. The predominant differences were observed in terpenoids group, since some of them were only identified in the flavoured olive oils, while others showed an increase with the maceration process. VOCs mass transfer from plants to olive oils could explain the observed results. Principal components analysis (PCA) applied to LLME/GC-qMS data allowed to distinguish the olive oils. The flavoured oils would increase the use of olive oil among consumers as consequence of the improvement of its aromatic profile and healthy properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluation of needle trap micro-extraction and automatic alveolar sampling for point-of-care breath analysis.

PubMed

Trefz, Phillip; Rösner, Lisa; Hein, Dietmar; Schubert, Jochen K; Miekisch, Wolfram

2013-04-01

Needle trap devices (NTDs) have shown many advantages such as improved detection limits, reduced sampling time and volume, improved stability, and reproducibility if compared with other techniques used in breath analysis such as solid-phase extraction and solid-phase micro-extraction. Effects of sampling flow (2-30 ml/min) and volume (10-100 ml) were investigated in dry gas standards containing hydrocarbons, aldehydes, and aromatic compounds and in humid breath samples. NTDs contained (single-bed) polymer packing and (triple-bed) combinations of divinylbenzene/Carbopack X/Carboxen 1000. Substances were desorbed from the NTDs by means of thermal expansion and analyzed by gas chromatography-mass spectrometry. An automated CO2-controlled sampling device for direct alveolar sampling at the point-of-care was developed and tested in pilot experiments. Adsorption efficiency for small volatile organic compounds decreased and breakthrough increased when sampling was done with polymer needles from a water-saturated matrix (breath) instead from dry gas. Humidity did not affect analysis with triple-bed NTDs. These NTDs showed only small dependencies on sampling flow and low breakthrough from 1-5 %. The new sampling device was able to control crucial parameters such as sampling flow and volume. With triple-bed NTDs, substance amounts increased linearly with increasing sample volume when alveolar breath was pre-concentrated automatically. When compared with manual sampling, automatic sampling showed comparable or better results. Thorough control of sampling and adequate choice of adsorption material is mandatory for application of needle trap micro-extraction in vivo. The new CO2-controlled sampling device allows direct alveolar sampling at the point-of-care without the need of any additional sampling, storage, or pre-concentration steps.

Simultaneous determination of atorvastatin and valsartan in human plasma by solid-based disperser liquid-liquid microextraction followed by high-performance liquid chromatography-diode array detection.

PubMed

Farajzadeh, Mir Ali; Khorram, Parisa; Pazhohan, Azar

2016-04-01

A simple, sensitive, and efficient method has been developed for simultaneous estimation of valsartan and atorvastatin in human plasma by combination of solid-based dispersive liquid-liquid microextraction and high performance liquid chromatography-diode array detection. In the proposed method, 1,2-dibromoethane (extraction solvent) is added on a sugar cube (as a solid disperser) and it is introduced into plasma sample containing the analytes. After manual shaking and centrifugation, the resultant sedimented phase is subjected to back extraction into a small volume of sodium hydrogen carbonate solution using air-assisted liquid-liquid microextraction. Then the cloudy solution is centrifuged and the obtained aqueous phase is transferred into a microtube and analyzed by the separation system. Under the optimal conditions, extraction recoveries are obtained in the range of 81-90%. Calibration curves plotted in drug-free plasma sample are linear in the ranges of 5-5000μgL(-1) for valsartan and 10-5000μgL(-1) for atorvastatin with the coefficients of determination higher than 0.997. Limits of detection and quantification of the studied analytes in plasma sample are 0.30-2.6 and 1.0-8.2μgL(-1), respectively. Intra-day (n=6) and inter-days (n=4) precisions of the method are satisfactory with relative standard deviations less than 7.4% (at three levels of 10, 500, and 2000μgL(-1), each analyte). These data suggest that the method can be successfully applied to determine trace amounts of valsartan and atorvastatin in human plasma samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Characterization of three agave species by gas chromatography and solid-phase microextraction-gas chromatography-mass spectrometry.

PubMed

Peña-Alvarez, Araceli; Díaz, Laura; Medina, Alejandra; Labastida, Carmen; Capella, Santiago; Vera, Luz Elena

2004-02-20

Steam distillation (SD) extraction-solid-phase microextraction coupled to GC-MS was developed for the determination of terpenes and Bligh-Dyer extraction-derivatization coupled with GC for the determination of fatty acids such as ethyl esters were used. It was found that the three different Agave species have the same profile of fatty acids; the quantity of these compounds is different in each Agave variety. On the other hand, different terpenes were identified in the three Agave plants studied: nine in A. salmiana, eight in A. angustifolia and 32 in A. tequilana Weber var. azul.

[Improvement of the determination method of benzene, toluene, ethylbenzene and xylene(BTEX) in water using activated carbon fiber solid-phase microextraction/gas chromatography-mass spectrometry(GC-MS)].

PubMed

Jia, Jin-ping; Feng, Xue; Fang, Neng-hu; Huang, Jia-liang

2002-01-01

The methods of direct injection, carbon disulfide extraction and activated carbon fiber solid-phase microextraction/GC-MS, usually used in the determination of BTEX in water matrix, are compared and discussed. Experimental data of linearity, precision and limit of detection illustrate that the last one is better than the two other methods. This method was tested by the practical sample experiments and expected to be a simple and sensitive new method for the analysis of BTEX in water.

Stirring-controlled solidified floating solid-liquid drop microextraction as a new solid phase-enhanced liquid-phase microextraction method by exploiting magnetic carbon nanotube-nickel hybrid.

PubMed

Ghazaghi, Mehri; Mousavi, Hassan Zavvar; Shirkhanloo, Hamid; Rashidi, Alimorad

2017-01-25

A specific technique is introduced to overcome limitations of classical solidification of floating organic drop microextraction, such as tedious and time-consuming centrifuge step and using disperser solvent, by facile and efficient participation of solid and liquid phases. In this proposed method of stirring-controlled solidified floating solid-liquid drop microextraction (SC-SF-SLDME), magnetic carbon nanotube-nickel hybrid (MNi-CNT) as a solid part of the extractors are dispersed ultrasonically in sample solution, and the procedure followed by dispersion of liquid phase (1-undecanol) through high-rate stirring and easily recollection of MNi-CNT in organic solvent droplets through hydrophobic force. With the reduction in speed of stirring, one solid-liquid drop is formed on top of the solution. MNi-CNT acts as both extractor and the coalescence helper between organic droplets for a facile recollection. MNi-CNT was prepared by spray pyrolysis of nickel oleate/toluene mixture at 1000 °C. Four tyrosine kinase inhibitors were selected as model analytes and the effecting parameters were investigated. The results confirmed that magnetic nanoadsorbent has an important role in the procedure and complete collection of dispersed solvent is not achieved in the absence of the solid phase. Also, short extraction time exhibited success of the proposed method and effect of dispersed solid/liquid phases. The limits of quantification (LOQs) for imatinib, sunitinib, erlotinib, and nilotinib were determined to be as low as 0.7, 1.7, 0.6, and 1.0 μg L -1 , respectively. The intra-day precisions (RSDs) were lower than 4.5%. Method performance was investigated by determination of mentioned tyrosine kinase inhibitors (TKIs) in human serum and cerebrospinal fluid samples with good recoveries in the range of 93-98%. Copyright © 2016 Elsevier B.V. All rights reserved.

Screen-printed electrode-based electrochemical detector coupled with in-situ ionic-liquid-assisted dispersive liquid-liquid microextraction for determination of 2,4,6-trinitrotoluene.

PubMed

Fernández, Elena; Vidal, Lorena; Iniesta, Jesús; Metters, Jonathan P; Banks, Craig E; Canals, Antonio

2014-03-01

A novel method is reported, whereby screen-printed electrodes (SPELs) are combined with dispersive liquid-liquid microextraction. In-situ ionic liquid (IL) formation was used as an extractant phase in the microextraction technique and proved to be a simple, fast and inexpensive analytical method. This approach uses miniaturized systems both in sample preparation and in the detection stage, helping to develop environmentally friendly analytical methods and portable devices to enable rapid and onsite measurement. The microextraction method is based on a simple metathesis reaction, in which a water-immiscible IL (1-hexyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide, [Hmim][NTf2]) is formed from a water-miscible IL (1-hexyl-3-methylimidazolium chloride, [Hmim][Cl]) and an ion-exchange reagent (lithium bis[(trifluoromethyl)sulfonyl]imide, LiNTf2) in sample solutions. The explosive 2,4,6-trinitrotoluene (TNT) was used as a model analyte to develop the method. The electrochemical behavior of TNT in [Hmim][NTf2] has been studied in SPELs. The extraction method was first optimized by use of a two-step multivariate optimization strategy, using Plackett-Burman and central composite designs. The method was then evaluated under optimum conditions and a good level of linearity was obtained, with a correlation coefficient of 0.9990. Limits of detection and quantification were 7 μg L(-1) and 9 μg L(-1), respectively. The repeatability of the proposed method was evaluated at two different spiking levels (20 and 50 μg L(-1)), and coefficients of variation of 7 % and 5 % (n = 5) were obtained. Tap water and industrial wastewater were selected as real-world water samples to assess the applicability of the method.

Binary Solvents Dispersive Liquid-Liquid Microextraction (BS-DLLME) Method for Determination of Tramadol in Urine Using High-Performance Liquid Chromatography.

PubMed

Kiarostami, Vahid; Rouini, Mohamad-Reza; Mohammadian, Razieh; Lavasani, Hoda; Ghazaghi, Mehri

2014-02-03

Tramadol is an opioid, synthetic analog of codeine and has been used for the treatment of acute or chronic pain may be abused. In this work, a developed Dispersive liquid liquid microextraction (DLLME) as binary solvents-based dispersive liquid-liquid microextraction (BS-DLLME) combined with high performance liquid chromatography (HPLC) with fluorescence detection (FD) was employed for determination of tramadol in the urine samples. This procedure involves the use of an appropriate mixture of binary extraction solvents (70 μL CHCl3 and 30 μL ethyl acetate) and disperser solvent (600 μL acetone) for the formation of cloudy solution in 5 ml urine sample comprising tramadol and NaCl (7.5%, w/v). After centrifuging, the small droplets of extraction solvents were precipitated. In the final step, the HPLC with fluorescence detection was used for determination of tramadol in the precipitated phase. Various factors on the efficiency of the proposed procedure were investigated and optimized. The detection limit (S/N = 3) and quantification limit (S/N = 10) were found 0.2 and 0.9 μg/L, respectively. The relative standard deviations (RSD) for the extraction of 30 μg L of tramadol was found 4.1% (n = 6). The relative recoveries of tramadol from urine samples at spiking levels of 10, 30 and 60 μg/L were in the range of 95.6 - 99.6%. Compared with other methods, this method provides good figures of merit such as good repeatability, high extraction efficiency, short analysis time, simple procedure and can be used as microextraction technique for routine analysis in clinical laboratories.

Binary Solvents Dispersive Liquid—Liquid Microextraction (BS-DLLME) Method for Determination of Tramadol in Urine Using High-Performance Liquid Chromatography

PubMed Central

2014-01-01

Background Tramadol is an opioid, synthetic analog of codeine and has been used for the treatment of acute or chronic pain may be abused. In this work, a developed Dispersive liquid liquid microextraction (DLLME) as binary solvents-based dispersive liquid-liquid microextraction (BS-DLLME) combined with high performance liquid chromatography (HPLC) with fluorescence detection (FD) was employed for determination of tramadol in the urine samples. This procedure involves the use of an appropriate mixture of binary extraction solvents (70 μL CHCl3 and 30 μL ethyl acetate) and disperser solvent (600 μL acetone) for the formation of cloudy solution in 5 ml urine sample comprising tramadol and NaCl (7.5%, w/v). After centrifuging, the small droplets of extraction solvents were precipitated. In the final step, the HPLC with fluorescence detection was used for determination of tramadol in the precipitated phase. Results Various factors on the efficiency of the proposed procedure were investigated and optimized. The detection limit (S/N = 3) and quantification limit (S/N = 10) were found 0.2 and 0.9 μg/L, respectively. The relative standard deviations (RSD) for the extraction of 30 μg L of tramadol was found 4.1% (n = 6). The relative recoveries of tramadol from urine samples at spiking levels of 10, 30 and 60 μg/L were in the range of 95.6 – 99.6%. Conclusions Compared with other methods, this method provides good figures of merit such as good repeatability, high extraction efficiency, short analysis time, simple procedure and can be used as microextraction technique for routine analysis in clinical laboratories. PMID:24495475

Rapid ionic liquid-based ultrasound assisted dual magnetic microextraction to preconcentrate and separate cadmium-4-(2-thiazolylazo)-resorcinol complex from environmental and biological samples.

PubMed

Khan, Sumaira; Kazi, Tasneem Gul; Soylak, Mustafa

2014-04-05

A rapid and innovative microextraction technique named as, ionic liquid-based ultrasound-assisted dual magnetic microextraction (IL-UA-DMME) was developed for the preconcentration and extraction of trace cadmium from environmental and biological samples, prior to analyzed by flame atomic absorption spectrometry (FAAS). The proposed method has many obvious advantages, including evading the use of organic solvents and achieved high extraction yields by the combination of dispersive liquid-liquid microextraction (DLLME) and magnetic mediated-solid phase extraction (MM-SPE). In this approach ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6] play an important role to extract the cadmium-4-(2-thiazolylazo)-resorcinol (Cd-TAR) complex from acid digested sample solutions and ultrasonic irradiation was applied to assist emulsification. After then, dispersed small amount of Fe3O4 magnetic nanoparticles (MNPs) in sample solutions to salvaged the IL and complete phase separation was attained. Some analytical parameters that influencing the efficiency of proposed (IL-UA-DMME) method, such as pH, volume of IL, ligand concentration, ultra-sonication time, amount of Fe3O4 MNPs, sample volume and matrix effect were optimized. Limit of detection (LOD) and enrichment factor (EF) of the method under optimal experimental conditions were found to be 0.40μgL(-1) and 100, respectively. The relative standard deviation (RSD) of 50μgL(-1) Cd was 4.29%. The validity and accuracy of proposed method, was assessed to analyzed certified reference materials of fortified lake water TMDA-54.4, SPS-WW2 waste water, spinach leaves 1570a and also checked by standard addition method. The obtained values showed good agreement with the certified values and sufficiently high recovery were found in the range of 98.1-101% for Cd. The proposed method was facile, rapid and successfully applied for the determination of Cd in environmental and different biological samples. Copyright © 2013 Elsevier B.V. All rights reserved.

An on-line push/pull perfusion-based hollow-fiber liquid-phase microextraction system for high-performance liquid chromatographic determination of alkylphenols in water samples.

PubMed

Chao, Yu-Ying; Jian, Zhi-Xuan; Tu, Yi-Ming; Wang, Hsaio-Wen; Huang, Yeou-Lih

2013-06-07

In this study, we employed a novel on-line method, push/pull perfusion hollow-fiber liquid-phase microextraction (PPP-HF-LPME), to extract 4-tert-butylphenol, 2,4-di-tert-butylphenol, 4-n-nonylphenol, and 4-n-octylphenol from river and tap water samples; we then separated and quantified the extracted analytes through high-performance liquid chromatography (HPLC). Using this approach, we overcame the problem of fluid loss across the porous HF membrane to the donor phase, permitting on-line coupling of HF-LPME to HPLC. In our PPP-HF-LPME system, we used a push/pull syringe pump as the driving source to perfuse the acceptor phase, while employing a heating mantle and an ultrasonic probe to accelerate mass transfer. We optimized the experimental conditions such as the nature of the HF supported intermediary phase and the acceptor phase, the composition of the donor and acceptor phases, the sample temperature, and the sonication conditions. Our proposed method provided relative standard deviations of 3.1-6.2%, coefficients of determination (r(2)) of 0.9989-0.9998, and limits of detection of 0.03-0.2 ng mL(-1) for the analytes under the optimized conditions. When we applied this method to analyses of river and tap water samples, our results confirmed that this microextraction technique allows reliable monitoring of alkylphenols in water samples.

Determination of trace levels of benzophenone-type ultra-violet filters in real matrices by bar adsorptive micro-extraction using selective sorbent phases.

PubMed

Almeida, C; Stępkowska, A; Alegre, A; Nogueira, J M F

2013-10-11

Bar adsorptive micro-extraction (BAμE), using selective sorbent phases, followed by liquid desorption in combination with high performance liquid chromatography-diode array detection (BAμE-LD/HPLC-DAD), is proposed for the determination of trace levels of four benzophenone-type UV filters (benzophenone, 2-hydroxy-4-methoxy-benzophenone, 2,4-hydroxybenzophenone and 4-hydroxybenzophenone) in real matrices. By comparing three polymers (P1, P2 and P3) and five activated carbons (AC1, AC2, AC3, AC4 and AC5) phases, P2 (a modified pyrrolidone polymer) and AC4 coatings showed much higher selectivity and capacity through BAμE, where the former offers multiple mechanisms of interaction and faster equilibrium kinetics. Assays performed on 25mL of ultra-pure water samples spiked at the 8.0μg/L level, yielded recoveries ranging from 76.6±8.3% to 103.5±6.4% depending on the sorbent phase used (P2 or AC4), under optimized experimental conditions. The analytical performance showed convenient detection limits (0.3-0.5μg/L) and good linear dynamic ranges (1.0-24.0μg/L) with remarkable determination coefficients (r(2)>0.9969). Excellent repeatability was also achieved through intraday (RSD<13.0%) and interday (RSD<8.9%) experiments. By using the standard addition methodology, the application of the present analytical approach on sea water, wastewater, commercial cosmetic products and urine samples revealed good sensitivity, absence of matrix effects and the occurrence of levels of some benzophenones. The proposed methodology that uses nanostructured particles and operates under the floating sampling technology proved to be a sorption-based static micro-extraction alternative to monitor benzophenone-type UV filters in real matrices. Moreover, is easy to implement, reliable, sensitive, requiring low sample volume and the possibility to choose the most selective sorbent coating according to the target compounds involved. Copyright © 2013. Published by Elsevier B.V.

Hydrophilic interaction chromatography combined with dispersive liquid-liquid microextraction as a preconcentration tool for the simultaneous determination of the panel of underivatized neurotransmitters in human urine samples.

PubMed

Konieczna, Lucyna; Roszkowska, Anna; Niedźwiecki, Maciej; Bączek, Tomasz

2016-01-29

A simple and sensitive method using dispersive liquid-liquid microextraction (DLLME) followed by liquid chromatography coupled to mass spectrometry (LC-MS) with a hydrophilic interaction chromatography (HILIC) column was developed for the simultaneous determination of 13 compounds of different polarities, comprising monoamine neurotransmitters (dopamine, norepinephrine, epinephrine and serotonin) along with their respective precursors and metabolites, in human urine samples. The microextraction procedure was based on the fast injection of a mixture of ethanol (disperser solvent) and dichloromethane (extraction solvent) into a human urine sample, forming a cloudy solution in the Eppendorf tube. After centrifugation, the sedimented phase was collected and subsequently analyzed by LC-HILIC-MS in about 12min without a derivatization step. The separation was performed on an XBridge Amide™ BEH column 3.0×100mm, 3.5mm and the mobile phase consisted of phase A: 10mM ammonium formate buffer in water pH 3.0 and phase B: 10 mM ammonium formate buffer in acetonitrile, under gradient program elution. Tyrosine, tryptophan, 5-hydroxytryptophan, dopamine, epinephrine, norepinephrine, serotonin, 3-methoxytyramine, 5-hydroxyindole-3-acetic acid, 3,4-dihydroxy-l-phenylalanine and norvaline (internal standard) were detected in the positive ionization mode. While vanillylmandelic acid, homovanillic acid, 3,4-dihydroxyphenylacetic acid and 3,4-dihydroxybenzylamine (internal standard) were detected in the negative ionization mode. Parameters influencing DLLME and LC-HILIC-MS were investigated. Under the optimum conditions, the proposed method exhibited a low detection limit (5-10ngmL(-1)), and good linearity with R between 0.9991 and 0.9998. The recoveries in human urine samples were 99.0%±3.6%. for the 13 studied biogenic amines with intra- and inter-day RSDs of 0.24-9.55% and 0.31-10.0%, respectively. The developed DLLME-LC-MS method could be successfully applied for the determination of trace amounts of polar endogenous compounds, such as neurotransmitters, in human urine samples, including samples with a reduced volume obtained from pediatric patients. Copyright © 2015 Elsevier B.V. All rights reserved.

Comparison of micellar extraction combined with ionic liquid based vortex-assisted liquid-liquid microextraction and modified quick, easy, cheap, effective, rugged, and safe method for the determination of difenoconazole in cowpea.

PubMed

Chen, Xiaochu; Bian, Yanli; Liu, Fengmao; Teng, Peipei; Sun, Pan

2017-10-06

Two simple sample pretreatment for the determination of difenoconazole in cowpea was developed including micellar extraction combined with ionic liquid based vortex-assisted liquid-liquid microextraction (ME-IL-VALLME) prior to high performance liquid chromatography (HPLC), and modified quick, easy, cheap, effective, rugged, and safe method (QuEChERS) coupled with HPLC-MS/MS. In ME-IL-VALLME method, the target analyte was extracted by surfactant Tween 20 micellar solution, then the supernatant was diluted with 3mL water to decrease the solubility of micellar solution. Subsequently, the vortex-assisted liquid-liquid microextraction (VALLME) procedure was performed in the diluted extraction solution by using the ionic liquid of 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIM]PF 6 ) as the extraction solvent and Tween 20 as an emulsifier to enhance the dispersion of the water-immiscible ionic liquid into the aqueous phase. Parameters that affect the extraction have been investigated in both methods Under the optimum conditions, the limits of quantitation were 0.10 and 0.05mgkg -1 , respectively. And good linearity was achieved with the correlation coefficient higher than 0.9941. The relative recoveries ranged from 78.6 to 94.8% and 92.0 to 118.0% with the relative standard deviations (RSD) of 7.9-9.6% and 1.2-3.2%, respectively. Both methods were quick, simple and inexpensive. However, the ME-IL-VALLME method provides higher enrichment factor compared with conventional QuEChERS method. The ME-IL-VALLME method has a strong potential for the determination of difenoconazole in complex vegetable matrices with HPLC. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of water-phase derivatization followed by solid-phase microextraction and gas chromatography/mass spectrometry for fast determination of valproic acid in human plasma.

PubMed

Deng, Chunhui; Li, Ning; Ji, Jie; Yang, Bei; Duan, Gengli; Zhang, Xiangmin

2006-01-01

In this study, a simple, rapid, and sensitive method was developed and validated for the quantification of valproic acid (VPA), an antiepileptic drug, in human plasma, which was based on water-phase derivatization followed by headspace solid-phase microextraction (HS-SPME) and gas chromatography/mass spectrometry (GC/MS). In the proposed method, VPA in plasma was rapidly derivatized with a mixture of isobutyl chloroformate, ethanol and pyridine under mild conditions (room temperature, aqueous medium), and the VPA ethyl ester formed was headspace-extracted and simultaneously concentrated using the SPME technique. Finally, the analyte extracted on SPME fiber was analyzed by GC/MS. The experimental parameters and method validations were studied. The optimal conditions were obtained: PDMS fiber, stirring rate of 1100 rpm, sample temperature of 80 degrees C, extraction time of 20 min, NaCl concentration of 30%. The proposed method had a limit of quantification (0.3 microg/mL), good recovery (89-97%) and precision (RSD value less than 10%). Because the proposed method combined a rapid water-phase derivatization with a fast, simple and solvent-free sample extraction and concentration technique of SPME, the sample preparation time was less than 25 min. This much shortens the whole analysis time of VPA in plasma. The validated method has been successfully used to analyze VPA in human plasma samples for application in pharmacokinetic studies. All these results show that water-phase derivatization followed by HS-SPME and GC/MS is an alternative and powerful method for fast determination of VPA in biological fluids. Copyright 2006 John Wiley & Sons, Ltd.

Layered double hydroxide films on nanoporous anodic aluminum oxide/aluminum wire: a new fiber for rapid analysis of Origanum vulgare essential oils.

PubMed

Piryaei, Marzieh

2018-01-01

Zn/Al layered double hydroxide (LDH) films were fabricated in situ with anodic aluminium oxide aluminium as both the substrate and the sole aluminium source by means of urea hydrolysis. Headspace solid phase microextraction using LDH fibre in combination with capillary GC-MS was utilised as a monitoring technique for the collection and detection of the volatile compounds of Origanum vulgare. Experimental parameters, including the sample weight, microwave power, extraction time and humidity effect, were examined and optimised.

Volatile compound in cut and un-cut flowers of tetraploid Freesia hybrida.

PubMed

Ao, Man; Liu, Baofeng; Wang, Li

2013-01-01

The flower volatile compounds (FVCs) of two tetraploid Freesia hybrida (pink-yellow and yellow) cultivars and their cut flowers were analysed by headspace solid-phase microextraction combined with gas chromatography-mass spectrometry. Twelve FVCs were identified in the pink-yellow cultivar, with linalool as the major compound; 30 FVCs were identified in the yellow cultivar, with linalool and terpineol as the two major compounds. The FVCs (>1%) of the two cut flower cultivars were very similar to that of the un-cut flowers, and no significant difference was observed.

Accelerated solvent extraction combined with dispersive liquid-liquid microextraction before gas chromatography with mass spectrometry for the sensitive determination of phenols in soil samples.

PubMed

Xing, Han-Zhu; Wang, Xia; Chen, Xiang-Feng; Wang, Ming-Lin; Zhao, Ru-Song

2015-05-01

A method combining accelerated solvent extraction with dispersive liquid-liquid microextraction was developed for the first time as a sample pretreatment for the rapid analysis of phenols (including phenol, m-cresol, 2,4-dichlorophenol, and 2,4,6-trichlorophenol) in soil samples. In the accelerated solvent extraction procedure, water was used as an extraction solvent, and phenols were extracted from soil samples into water. The dispersive liquid-liquid microextraction technique was then performed on the obtained aqueous solution. Important accelerated solvent extraction and dispersive liquid-liquid microextraction parameters were investigated and optimized. Under optimized conditions, the new method provided wide linearity (6.1-3080 ng/g), low limits of detection (0.06-1.83 ng/g), and excellent reproducibility (<10%) for phenols. Four real soil samples were analyzed by the proposed method to assess its applicability. Experimental results showed that the soil samples were free of our target compounds, and average recoveries were in the range of 87.9-110%. These findings indicate that accelerated solvent extraction with dispersive liquid-liquid microextraction as a sample pretreatment procedure coupled with gas chromatography and mass spectrometry is an excellent method for the rapid analysis of trace levels of phenols in environmental soil samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Combination of in situ metathesis reaction with a novel "magnetic effervescent tablet-assisted ionic liquid dispersive microextraction" for the determination of endogenous steroids in human fluids.

PubMed

Wu, Jia; Xu, Zilin; Pan, Yixuan; Shi, Yi; Bao, Xiujie; Li, Jun; Tong, Yu; Tang, Han; Ma, Shuyan; Wang, Xuedong; Lyu, Jianxin

2018-05-01

Herein, a novel magnetic effervescence tablet-assisted microextraction coupled to in situ metathesis reaction of ionic liquid (IS-META-ILDM) is presented for the determination of four endogenous steroids in human urine, pregnant women's blood, and fetal umbilical cord blood. The magnetic effervescent tablets, which were composed of Fe 3 O 4 nanoparticles, sodium carbonate (alkaline source), and tartaric acid (acidic source), were used to disperse the extractant and for convenient magnetic separation. After the effervescent reaction, in situ reaction between NH 4 PF 6 and [C 6 MIM]BF 4 was adopted to change hydrophilic ionic liquid to hydrophobic liquid, which could be separated from the aqueous phase. The newly developed method has three obvious advantages: (1) combination of effervescent dispersion and magnetic nanoparticles' retrieval is cost-effective and the dispersion and collection of the extractant can be completed almost simultaneously; (2) as compared to temperature-controlled ionic liquid dispersive microextraction and cold-induced solidified microextraction, this method avoids a heating and cooling process which significantly reduces the extraction time and energy cost; and (3) the combination of adsorption by magnetic nanoparticles with extraction by in situ metathesis reaction easily produces high recoveries for target analytes. The optimized composition of effervescent tablet and experimental parameters are as follows: 0.64 g mixture of sodium carbonate and tartaric acid, 7 mg of Fe 3 O 4 (20 nm) as magnetic sorbents, 40 μL of [C 6 MIM]BF 4 as the extraction solvent, 0.15 g NH 4 PF 6 , and 300 μL of elution solvent. Under the optimized conditions, the newly developed method provided high extraction recoveries (90.0-118.5%) and low LODs (0.14-0.17 μg L -1 ) in urine and blood samples. In total, this IS-META-ILDM method provided high extraction efficiency, fast and convenient separation, and underutilization of any organic solvent, and thus it has great potential for the determination of trace endogenous steroids in complex human fluids. Graphical abstract The newly developed method has three obvious advantages: combination of effervescent dispersion and magnetic nanoparticles' retrieval is cost-effective and the dispersion and collection of the extractant can be completed almost simultaneously. It avoids a heating and cooling process which significantly reduces the extraction time and energy cost and easily produces high recoveries for target analytes.

A novel application of three phase hollow fiber based liquid phase microextraction (HF-LPME) for the HPLC determination of two endocrine disrupting compounds (EDCs), n-octylphenol and n-nonylphenol, in environmental waters.

PubMed

Villar-Navarro, Mercedes; Ramos-Payán, María; Fernández-Torres, Rut; Callejón-Mochón, Manuel; Bello-López, Miguel Ángel

2013-01-15

This work proposes for the first time the use of a three phase hollow fiber liquid phase microextraction (HF-LPME) procedure for the extraction, and the later HPLC determination using fluorescence detection, of two much known endocrine disrupting compounds (EDCs): n-octylphenol (OP) and n-nonylphenol (NP). The extraction was carried out through a dihexyl ether liquid membrane supported on an Accurel® Q3/2 polypropylene hollow fiber. Optimum pH for donor and acceptor phases and extraction time were established. Enrichment (preconcentration) factors of 50 were obtained that allows detection limits of 0.54 and 0.52 ng mL(-1) for OP and NP, respectively. The method was successfully applied to the determination of these EDCs in environmental water samples, including urban wastewaters. Copyright © 2012 Elsevier B.V. All rights reserved.

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.

Determination of transformation products of unsymmetrical dimethylhydrazine in water using vacuum-assisted headspace solid-phase microextraction.

PubMed

Orazbayeva, Dina; Kenessov, Bulat; Psillakis, Elefteria; Nassyrova, Dayana; Bektassov, Marat

2018-06-22

A new, sensitive and simple method based on vacuum-assisted headspace solid-phase microextraction (Vac-HSSPME) followed by gas chromatography-mass-spectrometry (GC-MS), is proposed for the quantification of rocket fuel unsymmetrical dimethylhydrazine (UDMH) transformation products in water samples. The target transformation products were: pyrazine, 1-methyl-1H-pyrazole, N-nitrosodimethylamine, N,N-dimethylformamide, 1-methyl-1Н-1,2,4-triazole, 1-methyl-imidazole and 1H-pyrazole. For these analytes and within shorter sampling times, Vac-HSSPME yielded detection limits (0.5-100 ng L -1 ) 3-10 times lower than those reported for regular HSSPME. Vac-HSSPME sampling for 30 min at 50 °C yielded the best combination of analyte responses and their standard deviations (<15%). 1-Formyl-2,2-dimethylhydrazine and formamide were discarded because of the poor precision and accuracy when using Vac-HSSPME. The recoveries for the rest of the analytes ranged between 80 and 119%. The modified Mininert valve and Thermogreen septum could be used for automated extraction as it ensured stable analyte signals even after long waiting times (>24 h). Finally, multiple Vac-HSSME proved to be an efficient tool for controlling the matrix effect and quantifying UDMH transformation products. Copyright © 2018 Elsevier B.V. All rights reserved.

Silica-based ionogels: nanoconfined ionic liquid-rich fibers for headspace solid-phase microextraction coupled with gas chromatography-barrier discharge ionization detection.

PubMed

Pena-Pereira, Francisco; Marcinkowski, Lukasz; Kloskowski, Adam; Namieśnik, Jacek

2014-12-02

In this work, hybrid silica-based materials with immobilized ionic liquids (ILs) were prepared by sol-gel technology and evaluated as solid-phase microextraction (SPME) fiber coatings. High loadings of the IL 1-methyl-3-butylimidazolium bis(trifluoromethylsulfonyl)imide ([C4MIM][TFSI]) were confined within the hybrid network. Coatings composition and morphology were evaluated using scanning electron microscopy and energy dispersive X-ray spectrometry. The obtained ionogel SPME fibers exhibited high extractability for aromatic volatile compounds, yielding good sensitivity and precision when combined with a gas chromatograph with barrier ionization discharge (GC-BID) detection. A central composite design was used for assessing the effect of experimental parameters on the extraction process. Under optimized conditions, the proposed ionogel SPME fiber coatings enabled the achievement of excellent enrichment factors (up to 7400). The limits of detection (LODs) were found in the range 0.03-1.27 μg L(-1), whereas the repeatability and fiber-to-fiber reproducibility were 5.6% and 12.0% on average, respectively. Water samples were analyzed by the proposed methodology, showing recovery values in the range of 88.7-113.9%. The results obtained in this work suggest that ionogels can be promising coating materials for future applications of SPME and related sample preparation techniques.

Improvement of a headspace solid phase microextraction-gas chromatography/mass spectrometry method for the analysis of wheat bread volatile compounds.

PubMed

Raffo, Antonio; Carcea, Marina; Castagna, Claudia; Magrì, Andrea

2015-08-07

An improved method based on headspace solid phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME/GC-MS) was proposed for the semi-quantitative determination of wheat bread volatile compounds isolated from both whole slice and crust samples. A DVB/CAR/PDMS fibre was used to extract volatiles from the headspace of a bread powdered sample dispersed in a sodium chloride (20%) aqueous solution and kept for 60min at 50°C under controlled stirring. Thirty-nine out of all the extracted volatiles were fully identified, whereas for 95 other volatiles a tentative identification was proposed, to give a complete as possible profile of wheat bread volatile compounds. The use of an array of ten structurally and physicochemically similar internal standards allowed to markedly improve method precision with respect to previous HS-SPME/GC-MS methods for bread volatiles. Good linearity of the method was verified for a selection of volatiles from several chemical groups by calibration with matrix-matched extraction solutions. This simple, rapid, precise and sensitive method could represent a valuable tool to obtain semi-quantitative information when investigating the influence of technological factors on volatiles formation in wheat bread and other bakery products. Copyright © 2015 Elsevier B.V. All rights reserved.

Determination of organotin compounds by headspace solid-phase microextraction-gas chromatography-pulsed flame-photometric detection (HS-SPME-GC-PFPD).

PubMed

Bravo, Manuel; Lespes, Gaëtane; De Gregori, Ida; Pinochet, Hugo; Gautier, Martine Potin

2005-12-01

A method based on Headspace solid-phase microextraction (HS-SPME, with a 100 mum PDMS-fiber) in combination with gas-chromatography and pulsed flame-photometric detection (GC-PFPD) has been investigated for simultaneous determination of eight organotin compounds. Monobutyltin (MBT), dibutyltin (DBT), tributyltin (TBT), monophenyltin (MPhT), and the semi-volatile diphenyltin (DPhT), triphenyltin (TPhT), monooctyltin (MOcT), and dioctyltin (DOcT) were determined after derivatization with sodium tetraethylborate. The conditions used for the extraction and preconcentration step were optimised by experimental design methodology. Tripropyltin (TPrT) and diheptyltin (DHepT) were used as internal standards for quantification of volatile and semi-volatile organotin compounds, respectively. The analytical precision (RSD) for ten successive injections of a standard mixture containing all the organic tin compounds ranged between 2 and 11%. The limits of detection for all the organotin compounds were sub ng (Sn) L(-1) in water and close to ng (Sn) kg(-1) in sediments. The accuracy of the method was evaluated by analysis of two certified reference material (CRM) sediment samples. The HS-SPME-GC-PFPD was then applied to the analysis of three harbour sediment samples. The results showed that headspace SPME is an attractive tool for analysis of organotin compounds in solid environmental matrices.

Solid phase microextraction of phthalic acid esters from vegetable oils using iron (III)-based metal-organic framework/graphene oxide coating.

PubMed

Zhang, Shuaihua; Yang, Qian; Li, Zhi; Wang, Wenjin; Zang, Xiaohuan; Wang, Chun; Wang, Zhi

2018-10-15

A hybrid composite featuring an iron-based metal-organic framework Material of Institute Lavoisier-88(Fe) and graphene oxide (MIL-88(Fe)/GO) was synthesized and used as the solid-phase microextraction (SPME) coating. The SPME fiber was prepared by covalent bonding of the MIL-88(Fe)/GO composite onto the stainless steel substrate. The fiber had a good durability and allowed >100 replicate extractions. The developed method, which combined the MIL-88(Fe)/GO coated fiber based SPME with gas chromatography-flame ionization detection (GC-FID), achieved low limits of detection (0.5-2.0 ng g -1 , S/N = 3) and good linearity (r 2  > 0.994) for the phthalic acid esters (PAEs) from various vegetable oil samples. The repeatability and fiber-to-fiber reproducibility were in the range of 4.0-9.1% and 5.7-11.4%, respectively. The method was successfully applied to the analysis of PAEs from vegetable oil samples with good recoveries (83.1-104.1%) and satisfactory precisions (RSDs < 10.5%), indicating that the MIL-88(Fe)/GO hybrid composite is a good coating material for the SPME of PAEs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Combination of solid-phase extraction with dispersive liquid-liquid microextraction followed by GC-MS for determination of pesticide residues from water, milk, honey and fruit juice.

PubMed

Shamsipur, Mojtaba; Yazdanfar, Najmeh; Ghambarian, Mahnaz

2016-08-01

In this work, an effective preconcentration method for the extraction and determination of traces of multi-residue pesticides was developed using solid-phase extraction (SPE) coupled with dispersive liquid-liquid microextraction and gas chromatography-mass spectrometry (GC-MS). Variables affecting the performance of both extraction steps such as type and volume of elution and extraction solvents, breakthrough volume, salt addition, extraction time were thoroughly investigated. The proposed method resulted in good linearities (R(2)>0.9915) over the ranges of 1-10,000ngkg(-1), limits of detection (LODs) in the range of 0.5-1.0ngkg(-1) at S/N=3, and precision of RSD% of ⩽11.8. Under optimal conditions, the preconcentration factors were obtained in the range of 2362-10,593 for 100mL sample solutions. Comparison of the proposed method with other ones demonstrated that SPE-DLLME method provides higher extraction efficiency and larger preconcentration factor for determination of pesticides residues. Further, it is simple, inexpensive, highly sensitive, and can be successfully applied to separation, preconcentration and determination of the pesticides (and other noxious materials) in different real food samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development of a simple and sensitive method for the characterization of odorous waste gas emissions by means of solid-phase microextraction (SPME) and GC-MS/olfactometry.

PubMed

Kleeberg, K K; Liu, Y; Jans, M; Schlegelmilch, M; Streese, J; Stegmann, R

2005-01-01

A solid-phase microextraction (SPME) method has been developed for the extraction of odorous compounds from waste gas. The enriched compounds were characterized by gas chromatography-mass spectrometry (GC-MS) and gas chromatography followed by simultaneous flame ionization detection and olfactometry (GC-FID/O). Five different SPME fiber coatings were tested, and the carboxen/polydimethylsiloxane (CAR/PDMS) fiber showed the highest ability to extract odorous compounds from the waste gas. Furthermore, parameters such as exposure time, desorption temperature, and desorption time have been optimized. The SPME method was successfully used to characterize an odorous waste gas from a fat refinery prior to and after waste gas treatment in order to describe the treatment efficiency of the used laboratory scale plant which consisted of a bioscrubber/biofilter combination and an activated carbon adsorber. The developed method is a valuable approach to provide detailed information of waste gas composition and complements existing methods for the determination of odors. However, caution should be exercised if CAR/PDMS fibers are used for the quantification of odorous compounds in multi-component matrices like waste gas emissions since the relative affinity of each analyte was shown to differ according to the total amount of analytes present in the sample.

Measurement of isoprene solubility in water, human blood and plasma by multiple headspace extraction gas chromatography coupled with solid phase microextraction.

PubMed

Mochalski, Paweł; King, Julian; Kupferthaler, Alexander; Unterkofler, Karl; Hinterhuber, Hartmann; Amann, Anton

2011-12-01

The aim of this study was to determine the solubility (liquid-to-air ratios) of isoprene in water, human blood and plasma. To this end, an experimental setup combining multiple headspace extraction, solid phase microextraction and gas chromatography-mass spectrometry was applied. The water:air partition coefficients of isoprene were determined for the temperature range 4.5-37 °C and amounted to 1.171-0.277 (g mL(l)(-1)) (g mL(a)(-1))(-1). On the basis of these data, the enthalpy of volatilization was calculated as 29.46 ± 2.83 kJ mol(-1). The blood:air partition coefficients at 37 °C were determined for ten normal healthy volunteers spread around a median value of 0.95 ± 0.09 (g mL(l)(-1)) (g mL(a)(-1))(-1) and were approximately 16% lower than the plasma:air partition coefficients (1.11 ± 0.2). The applied methodology can be particularly attractive for solubility studies targeting species at very low concentrations in the solution, i.e. when headspace sample enrichment is necessary to provide sufficient measurement sensitivity and reliability. This can be especially helpful if environmental or physiological solute levels have to be considered.

Comparison of two extraction techniques, solid-phase microextraction versus continuous liquid-liquid extraction/solvent-assisted flavor evaporation, for the analysis of flavor compounds in gueuze lambic beer.

PubMed

Thompson-Witrick, Katherine A; Rouseff, Russell L; Cadawallader, Keith R; Duncan, Susan E; Eigel, William N; Tanko, James M; O'Keefe, Sean F

2015-03-01

Lambic is a beer style that undergoes spontaneous fermentation and is traditionally produced in the Payottenland region of Belgium, a valley on the Senne River west of Brussels. This region appears to have the perfect combination of airborne microorganisms required for lambic's spontaneous fermentation. Gueuze lambic is a substyle of lambic that is made by mixing young (approximately 1 year) and old (approximately 2 to 3 years) lambics with subsequent bottle conditioning. We compared 2 extraction techniques, solid-phase microextraction (SPME) and continuous liquid-liquid extraction/solvent-assisted flavor evaporation (CCLE/SAFE), for the isolation of volatile compounds in commercially produced gueuze lambic beer. Fifty-four volatile compounds were identified and could be divided into acids (14), alcohols (12), aldehydes (3), esters (20), phenols (3), and miscellaneous (2). SPME extracted a total of 40 volatile compounds, whereas CLLE/SAFE extracted 36 volatile compounds. CLLE/SAFE extracted a greater number of acids than SPME, whereas SPME was able to isolate a greater number of esters. Neither extraction technique proved to be clearly superior and both extraction methods can be utilized for the isolation of volatile compounds found in gueuze lambic beer. © 2015 Institute of Food Technologists®

Determination of benzimidazole anthelmintics in milk and honey by monolithic fiber-based solid-phase microextraction combined with high-performance liquid chromatography-diode array detection.

PubMed

Zhang, Yong; Huang, Xiaojia; Yuan, Dongxing

2015-01-01

A porous poly(methacrylic acid-co-ethylene dimethacrylate) monolithic fiber (MEMF) for solid-phase microextraction (SPME) of five benzimidazole anthelmintics was prepared by in-situ polymerization. The effect of polymerization conditions on SPME of the target analytes was studied thoroughly. The physicochemical properties of the monolith were characterized by infrared spectroscopy, elemental analysis, scanning electron microscopy, and mercury intrusion porosimetry. Several conditions affecting the extraction efficiency were investigated and, under the optimized conditions, a simple and sensitive method for the determination of trace benzimidazoles residues in milk and honey was established by coupling MEMF-SPME with high-performance liquid chromatography-diode array detection (MEMF-SPME-HPLC-DAD). Under the optimum experimental conditions, the limits of detection (S/N = 3) of the method were 0.11-0.30 μg L(-1) for milk and 0.086-0.28 μg L(-1) for honey. Evaluation of intra-day and inter-day precision showed reproducibility was satisfactory-relative standard deviations (RSD) for both were <10 %. Finally, the method was successfully used for determination of benzimidazole residues in milk and honey. Recoveries obtained for determination of benzimidazole anthelmintics in spiked samples ranged from 72.3 to 121 %, with RSD always <11 %.

Solvent-modified solid-phase microextraction for the determination of diazepam in human plasma samples by capillary gas chromatography.

PubMed

Krogh, M; Grefslie, H; Rasmussen, K E

1997-02-21

This paper describes microextraction and gas chromatographic analysis of diazepam from human plasma. The method was based on immobilisation of 1.5 microliters of 1-octanol on a polyacrylate-coated fiber designed for solid-phase microextraction. The solvent-modified fibre was used to extract diazepam from the samples. The plasma sample was pre-treated to release diazepam from the protein binding. The fibre was inserted into the modified plasma sample, adjusted to pH 5.5 an internal standard was added and the mixture was carefully stirred for 4 min. The fibre with the immobilised solvent and the enriched analytes was injected into the capillary gas chromatograph. The solvent and the extracted analytes were evaporated at 300 degrees C in the split-splitless injection port of the gas chromatograph, separated on a methylsilicon capillary column and detected with a nitrogen-phosphorus detector. The method was shown to be reproducible with a detection limit of 0.10 nmol/ml in human plasma.

Simultaneous speciation of inorganic arsenic, selenium and tellurium in environmental water samples by dispersive liquid liquid microextraction combined with electrothermal vaporization inductively coupled plasma mass spectrometry.

PubMed

Liu, Ying; He, Man; Chen, Beibei; Hu, Bin

2015-09-01

A new method based on dispersive liquid liquid microextraction (DLLME) combined with electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) was developed for the simultaneous speciation of inorganic arsenic (As), selenium (Se) and tellurium (Te) with sodium diethyldithiocarbamate (DDTC) as both chelating reagent and chemical modifier. As(III), Se(IV) and Te(IV) were transformed into DDTC-chelates at pH 7 and extracted into the fine droplets formed by injecting the binary solution of bromobenzene (extraction solvent) and methanol (dispersive solvent) into the sample solution. After phase separation by centrifugation, As(III), Se(IV) and Te(IV) preconcentrated in the organic phase were determined by ETV-ICP-MS. Total inorganic As, Se and Te were obtained by reducing As(V), Se(VI) and Te(VI) to As(III), Se(IV) and Te(IV) with L-cysteine, which were then subjected to the same DLLME-ETV-ICP-MS process. The concentration of As(V), Se(VI), Te(VI) were calculated by subtracting the concentration of As(III), Se(IV) and Te(IV) from the total inorganic As, Se and Te, respectively. The main factors affecting the microextraction efficiency and the vaporization behavior of target species were investigated in detail. Under the optimal conditions, the limits of detection were 2.5, 8.6 and 0.56 ng L(-1) for As(III), Se(IV) and Te(IV), respectively, with the relative standard deviations (n=7) of 8.5-9.7%. The developed method was applied to the speciation of inorganic As, Se and Te in Certified Reference Materials of GSBZ50004-88, GBW(E)080395 and GBW(E)080548 environmental waters, and the determined values are in good agreement with the certified values. The method was also successfully applied to the simultaneous speciation of inorganic As, Se and Te in different environmental water samples with the recoveries in the range of 86.3-107% for the spiked samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Combined dispersive solid-phase extraction-dispersive liquid-liquid microextraction-derivatization for gas chromatography-mass spectrometric determination of aliphatic amines on atmospheric fine particles.

PubMed

Majedi, Seyed Mohammad; Lee, Hian Kee

2017-02-24

Short-chain aliphatic amines are ubiquitous in the atmospheric environment. They play an important role in the formation and growth of atmospheric particles. As such, there is a pressing need to monitor these particle-bound compounds present at trace quantities. The present work describes an efficient, one-step microextraction technique for the preconcentration and detection of trace levels of 10 aliphatic amines on fine particles (particulate matter of 2.5μm or less (PM 2.5 )) in the atmosphere. After extraction of amines from particles in acidified water samples, carbon-based sorbents (in dispersive solid-phase extraction mode), and vortex agitation were utilized for simultaneous derivatization-extraction and dispersive liquid-liquid microextraction. The approach significantly increased the recoveries and enrichment of the amine derivatives. This one-step, combined technique is proposed for the first time. Several influential factors including type and concentration of derivatization reagent (for gas chromatographic separation), type of buffer, sample pH, types and volumes of extraction and disperser solvents, type and amount of sorbent, vortex time and temperature, desorption solvent type and volume, and salt content were investigated and optimized. Under the optimum conditions, high enrichment factors (in the range of between 307 and 382) and good reproducibility (relative standard deviations, below 7.0%, n=5) were achieved. The linearity ranged from 0.1μg/L-100μg/L, and from 0.5μg/L-100μg/L, depending on the analytes. The limits of detection were between 0.02μg/L (corresponding to ∼0.01ng/m 3 in air) and 0.09μg/L (corresponding to ∼0.04ng/m 3 in air). The developed method was successfully applied to the analysis of PM 2.5 samples collected by air sampling through polytetrafluoroethylene filters. The concentration levels of amines ranged from 1.04 to 4.16ng/m 3 in the air sampled. Copyright © 2016 Elsevier B.V. All rights reserved.

Identification of volatile organic compounds emitted by a naturally aged book using solid-phase microextraction/gas chromatography/mass spectrometry.

PubMed

Lattuati-Derieux, Agnès; Bonnassies-Termes, Sylvette; Lavédrine, Bertrand

2004-02-13

Solid-phase microextraction (SPME) coupled to gas chromatography/mass spectrometry (GC/MS) has been applied to the analysis of volatile organic compounds emitted from a naturally aged groundwood pulp paper originating from an old book in order to access the products produced through the decomposition reactions occurring in paper upon ageing. Two different extraction methods were developed and compared: headspace SPME and contact SPME. The influence of few extraction parameters were tested in order to define the best extraction conditions. An optimised non-destructive contact SPME method was elaborated and allowed the characterisation of more than 50 individual constituents.

The measurement of ecstasy in human hair by triple phase directly suspended droplet microextraction prior to HPLC-DAD analysis.

PubMed

Es'haghi, Zarrin; Mohtaji, Maryam; Hasanzade-Meidani, Mahin; Masrournia, Mahboubeh

2010-04-01

New pre-concentration technique, triple phase suspended droplet microextraction (SD-LPME) and liquid chromatography-photodiode array detection was applied to determine ecstasy, MDMA (3,4-methylendioxy-N-methylamphetamine) in hair samples. In this research MDMA in hair was digested and after treatment extracted. The effective parameters were investigated and method was evaluated. Under the optimal conditions, the MDMA was enriched by factor 98.11. Linearity (r=0.9921), was obtained in the range of 10-15,000 ng mL(-1) and detection limit was 0.1 ng mL(-1). 2010 Elsevier B.V. All rights reserved.

Solid phase microextraction field kit

DOEpatents

Nunes, Peter J.; Andresen, Brian D.

2005-08-16

A field kit for the collection, isolation and concentration of trace amounts of high explosives (HE), biological weapons (BW) and chemical weapons (CW) residues in air, soil, vegetation, swipe, and liquid samples. The field kit includes a number of Solid Phase Microextraction (SPME) fiber and syringe assemblies in a hermetically sealed transportation container or tubes which includes a sampling port, a number of extra SPME fiber and syringe assemblies, the fiber and syringe assemblies including a protective cap for the fiber, and an extractor for the protective cap, along with other items including spare parts, protective glove, and an instruction manual, all located in an airtight container.

A novel sorbent based on carbon nanotube/amino-functionalized sol-gel for the headspace solid-phase microextraction of α-bisabolol from medicinal plant samples using experimental design.

PubMed

Yarazavi, Mina; Noroozian, Ebrahim

2018-02-13

A novel sol-gel coating on a stainless-steel fiber was developed for the first time for the headspace solid-phase microextraction and determination of α-bisabolol with gas chromatography and flame ionization detection. The parameters influencing the efficiency of solid-phase microextraction process, such as extraction time and temperature, pH, and ionic strength, were optimized by the experimental design method. Under optimized conditions, the linear range was between 0.0027 and 100 μg/mL. The relative standard deviations determined at 0.01 and 1.0 μg/mL concentration levels (n = 3), respectively, were as follows: intraday relative standard deviations 3.4 and 3.3%; interday relative standard deviations 5.0 and 4.3%; and fiber-to-fiber relative standard deviations 6.0 and 3.5%. The relative recovery values were 90.3 and 101.4% at 0.01 and 1.0 μg/mL spiking levels, respectively. The proposed method was successfully applied to various real samples containing α-bisabolol. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ionic liquid supported on an electrodeposited polycarbazole film for the headspace solid-phase microextraction and gas chromatography determination of aromatic esters.

PubMed

Feng, Yuanyuan; Zhao, Faqiong; Zeng, Baizhao

2015-05-01

A polycarbazole film was electrodeposited on a stainless-steel wire from a solution of N,N-dimethylformamide/propylene carbonate (1:9 v/v) containing 0.10 M carbazole and 0.10 M tetrabutylammonium perchlorate. The obtained polycarbazole fiber was immersed into an ionic liquid (1-hydroxyethyl-3-methyl imidazolium bis[(trifluoromethyl)sulfonyl]imide) solution (in dimethylsulfoxide) for 30 min, followed by drying under an infrared lamp. The resulting polycarbazole/ionic liquid fiber was applied to the headspace solid-phase microextraction and determination of aromatic esters by coupling with gas chromatography and flame ionization detection. Under the optimized conditions, the limits of detection were below 61 ng/L (S/N = 3) and the linear ranges were 0.061-500 μg/L with correlation coefficients above 0.9876. The relative standard deviations were below 4.8% (n = 5) for a single fiber, and below 9.9% for multi-fiber (n = 4). This fiber also exhibited good stability. It could be used for more than 160 times of headspace solid-phase microextraction and could withstand a high temperature up to 350°C. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of endocrine-disrupting compounds in water samples by magnetic nanoparticle-assisted dispersive liquid-liquid microextraction combined with gas chromatography-tandem mass spectrometry.

PubMed

Pérez, Rosa Ana; Albero, Beatriz; Tadeo, José Luis; Sánchez-Brunete, Consuelo

2016-11-01

A rapid extraction procedure is presented for the determination of five endocrine-disrupting compounds, estrone, ethinylestradiol, bisphenol A, triclosan, and 2-ethylhexylsalicylate, in water samples. The analysis involves a two-step extraction procedure that combines dispersive liquid-liquid microextraction (DLLME) with dispersive micro-solid phase extraction (D-μ-SPE), using magnetic nanoparticles, followed by in situ derivatization in the injection port of a gas chromatograph coupled to triple quadrupole mass spectrometry. The use of uncoated or oleate-coated Fe 3 O 4 nanoparticles as sorbent in the extraction process was evaluated and compared. The main parameters involved in the extraction process were optimized applying experimental designs. Uncoated Fe 3 O 4 nanoparticles were selected in order to simplify and make more cost-effective the procedure. DLLME was carried out at pH 3, during 2 min, followed by the addition of the nanoparticles for D-μ-SPE employing 1 min in the extraction. Analysis of spiked water samples of different sources gave satisfactory recovery results for all the compounds with detection limits ranging from 7 to 180 ng l -1 . Finally, the procedure was applied in tap, well, and river water. Graphical abstract Diagram of the extraction method using magnetic nanoparticles (MNPs).

Determination of ten pyrethroids in various fruit juices: comparison of dispersive liquid-liquid microextraction sample preparation and QuEChERS method combined with dispersive liquid-liquid microextraction.

PubMed

Zhang, Yaohai; Zhang, Xuelian; Jiao, Bining

2014-09-15

Dispersive liquid-liquid microextraction (DLLME) sample preparation and the quick, easy, cheap, effective, rugged and safe (QuEChERS) method combined with DLLME were developed and compared for the analysis of ten pyrethroids in various fruit juices using gas chromatography-electron capture detection (GC-ECD). QuEChERS-DLLME method has found its widespread applications to all the fruit juices including those samples with more complex matrices (orange, lemon, kiwi and mango) while DLLME was confined to the fruit juices with simpler matrices (apple, pear, grape and peach). The two methods provided acceptable recoveries and repeatability. In addition, the applicabilities of two methods were demonstrated with the real samples and further confirmed by gas chromatography-mass spectrometry (GC-MS). Copyright © 2014. Published by Elsevier Ltd.

Determination of imidazole derivatives by micellar electrokinetic chromatography combined with solid-phase microextraction using activated carbon-polymer monolith as adsorbent.

PubMed

Shih, Yung-Han; Lirio, Stephen; Li, Chih-Keng; Liu, Wan-Ling; Huang, Hsi-Ya

2016-01-08

In this study, an effective method for the separation of imidazole derivatives 2-methylimidazole (2-MEI), 4- methylimidazole (4-MEI) and 2-acetyl-4-tetrahydroxybutylimidazole (THI) in caramel colors using cation-selective exhaustive injection and sweeping micellar electrokinetic chromatography (CSEI-sweeping-MEKC) was developed. The limits of detection (LOD) and quantitation (LOQ) for the CSEI-sweeping-MEKC method were in the range of 4.3-80μgL(-1) and 14-270μgL(-1), respectively. Meanwhile, a rapid fabrication activated carbon-polymer (AC-polymer) monolithic column as adsorbent for solid-phase microextraction (SPME) of imidazole colors was developed. Under the optimized SPME condition, the extraction recoveries for intra-day, inter-day and column-to-column were in the range of 84.5-95.1% (<6.3% RSDs), 85.6-96.1% (<4.9% RSDs), and 81.3-96.1% (<7.1% RSDs), respectively. The LODs and LOQs of AC-polymer monolithic column combined with CSEI-sweeping-MEKC method were in the range of 33.4-60.4μgL(-1) and 111.7-201.2μgL(-1), respectively. The use of AC-polymer as SPME adsorbent demonstrated the reduction of matrix effect in food samples such as soft drink and alcoholic beverage thereby benefiting successful determination of trace-level caramel colors residues using CSEI-sweeping-MEKC method. The developed AC-polymer monolithic column can be reused for more than 30 times without any significant loss in the extraction recovery for imidazole derivatives. Copyright © 2015 Elsevier B.V. All rights reserved.

Halloysite nanotubes-titanium dioxide as a solid-phase microextraction coating combined with negative corona discharge-ion mobility spectrometry for the determination of parathion.

PubMed

Saraji, Mohammad; Jafari, Mohammad Taghi; Mossaddegh, Mehdi

2016-07-05

Halloysite nanotubes-titanium dioxide (HNTs-TiO2) as a biocompatible environmentally friendly solid-phase microextraction (SPME) fiber coating was prepared. HNTs-TiO2 was chemically coated on the surface of a fused-silica fiber using a sol-gel process. Parathion as an organophosphorus pesticide was selected as a model compound to investigate the extraction efficiency of the fiber. The extracted analyte was detected by negative corona discharge-ion mobility spectrometer (NCD-IMS). The effective parameters on the extraction efficiency, such as salt effect, extraction temperature and extraction time were investigated and optimized. The extraction efficiency of HNTs-TiO2 fiber was compared with bare-silica (sol-gel based coating without HNTs-TiO2), HNTs, carbon nanotubes and commercial SPME fibers (PA, PDMS, and PDMS-DVB). The HNTs-TiO2 fiber showed highest extraction efficiency among the studied fibers. The intra- and inter-day relative standard deviations were found to be 4.3 and 6.3%, respectively. The limit of detection and limit of quantification values were 0.03 and 0.1 μg L(-1), respectively. The dynamic range of the method was in the range of 0.1-25 μg L(-1). The spiking recoveries were between 85 (±9) and 97 (±6). The SPME-HNTs-TiO2 combined with NCD-IMS was successfully applied for the determination of parathion in apple, strawberry, celery and water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Development of a bar adsorptive micro-extraction-large-volume injection-gas chromatography-mass spectrometric method for pharmaceuticals and personal care products in environmental water matrices.

PubMed

Neng, N R; Nogueira, J M F

2012-01-01

The combination of bar adsorptive micro-extraction using activated carbon (AC) and polystyrene-divinylbenzene copolymer (PS-DVB) sorbent phases, followed by liquid desorption and large-volume injection gas chromatography coupled to mass spectrometry, under selected ion monitoring mode acquisition, was developed for the first time to monitor pharmaceutical and personal care products (PPCPs) in environmental water matrices. Assays performed on 25 mL water samples spiked (100 ng L(-1)) with caffeine, gemfibrozil, triclosan, propranolol, carbamazepine and diazepam, selected as model compounds, yielded recoveries ranging from 74% to 99% under optimised experimental conditions (equilibrium time, 16 h (1,000 rpm); matrix characteristics: pH 5, 5% NaCl for AC phase; LD: methanol/acetonitrile (1:1), 45 min). The analytical performance showed good precision (RSD < 18%), convenient detection limits (5-20 ng L(-1)) and excellent linear dynamic range (20-800 ng L(-1)) with remarkable determination coefficients (r(2) > 0.99), where the PS-DVB sorbent phase showed a much better efficiency. By using the standard addition methodology, the application of the present analytical approach on tap, ground, sea, estuary and wastewater samples allowed very good performance at the trace level. The proposed method proved to be a suitable sorption-based micro-extraction alternative for the analysis of priority pollutants with medium-polar to polar characteristics, showing to be easy to implement, reliable, sensitive and requiring a low sample volume to monitor PPCPs in water matrices.

Hollow Fiber Supported Liquid Membrane Extraction Combined with HPLC-UV for Simultaneous Preconcentration and Determination of Urinary Hippuric Acid and Mandelic Acid

PubMed Central

Bahrami, Abdulrahman; Ghamari, Farhad; Yamini, Yadollah; Ghorbani Shahna, Farshid; Moghimbeigi, Abbas

2017-01-01

This work describes a new extraction method with hollow-fiber liquid-phase microextraction based on facilitated pH gradient transport for analyzing hippuric acid and mandelic acid in aqueous samples. The factors affecting the metabolites extraction were optimized as follows: the volume of sample solution was 10 mL with pH 2 containing 0.5 mol·L−1 sodium chloride, liquid membrane containing 1-octanol with 20% (w/v) tributyl phosphate as the carrier, the time of extraction was 150 min, and stirring rate was 500 rpm. The organic phase immobilized in the pores of a hollow fiber was back-extracted into 24 µL of a solution containing sodium carbonate with pH 11, which was placed inside the lumen of the fiber. Under optimized conditions, the high enrichment factors of 172 and 195 folds, detection limit of 0.007 and 0.009 µg·mL−1 were obtained. The relative standard deviation (RSD) (%) values for intra- and inter-day precisions were calculated at 2.5%–8.2% and 4.1%–10.7%, respectively. The proposed method was successfully applied to the analysis of these metabolites in real urine samples. The results indicated that hollow-fiber liquid-phase microextraction (HF-LPME) based on facilitated pH gradient transport can be used as a sensitive and effective method for the determination of mandelic acid and hippuric acid in urine specimens. PMID:28208685

Determination of three estrogens and bisphenol A by functional ionic liquid dispersive liquid-phase microextraction coupled with ultra-high performance liquid chromatography and ultraviolet detection.

PubMed

Jiang, Yuehuang; Tang, Tingting; Cao, Zhen; Shi, Guoyue; Zhou, Tianshu

2015-06-01

A hydroxyl-functionalized ionic liquid, 1-hydroxyethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, was employed in an improved dispersive liquid-phase microextraction method coupled with ultra high performance liquid chromatography for the enrichment and determination of three estrogens and bisphenol A in environmental water samples. The introduced hydroxyl group acted as the H-bond acceptor that dispersed the ionic liquid effectively in the aqueous phase without dispersive solvent or external force. Fourier transform infrared spectroscopy indicated that the hydroxyl group of the cation of the ionic liquid enhanced the combination of extractant and analytes through the formation of hydrogen bonds. The improvement of the extraction efficiency compared with that with the use of alkyl ionic liquid was proved by a comparison study. The main parameters including volume of extractant, temperature, pH, and extraction time were investigated. The calibration curves were linear in the range of 5.0-1000 μg/L for estrone, estradiol, and bisphenol A, and 10.0-1000 μg/L for estriol. The detection limits were in the range of 1.7-3.4 μg/L. The extraction efficiency was evaluated by enrichment factor that were between 85 and 129. The proposed method was proved to be simple, low cost, and environmentally friendly for the determination of the four endocrine disruptors in environmental water samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Current trends in sample preparation for cosmetic analysis.

PubMed

Zhong, Zhixiong; Li, Gongke

2017-01-01

The widespread applications of cosmetics in modern life make their analysis particularly important from a safety point of view. There is a wide variety of restricted ingredients and prohibited substances that primarily influence the safety of cosmetics. Sample preparation for cosmetic analysis is a crucial step as the complex matrices may seriously interfere with the determination of target analytes. In this review, some new developments (2010-2016) in sample preparation techniques for cosmetic analysis, including liquid-phase microextraction, solid-phase microextraction, matrix solid-phase dispersion, pressurized liquid extraction, cloud point extraction, ultrasound-assisted extraction, and microwave digestion, are presented. Furthermore, the research and progress in sample preparation techniques and their applications in the separation and purification of allowed ingredients and prohibited substances are reviewed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of atenolol in human plasma using ionic-liquid-based ultrasound-assisted in situ solvent formation microextraction followed by high-performance liquid chromatography.

PubMed

Zeeb, Mohsen; Farahani, Hadi; Papan, Mohammad Kazem

2016-06-01

An efficient analytical method called ionic-liquid-based ultrasound-assisted in situ solvent formation microextraction followed by high-performance liquid chromatography was developed for the determination of atenolol in human plasma. A hydrophobic ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) was formed by the addition of a hydrophilic ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate) to a sample solution containing an ion-pairing agent during microextraction. The analyte was extracted into the ionic liquid phase while the microextraction solvent was dispersed throughout the sample by utilizing ultrasound. The sample was then centrifuged, and the extracting phase retracted into the microsyringe and injected to liquid chromatography. After optimization, the calibration curve showed linearity in the range of 2-750 ng/mL with the regression coefficient corresponding to 0.998. The limits of detection (S/N = 3) and quantification (S/N = 10) were 0.5 and 2 ng/mL, respectively. A reasonable relative recovery range of 90-96.7% and satisfactory intra-assay (4.8-5.1%, n = 6) and interassay (5.0-5.6%, n = 9) precision along with a substantial sample clean-up demonstrated good performance of the procedure. It was applied for the determination of atenolol in human plasma after oral administration and some pharmacokinetic data were obtained. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous sampling and analysis of indoor air infested with Cimex lectularius L. (Hemiptera: Cimicidae) by solid phase microextraction, thin film microextraction and needle trap device.

PubMed

Eom, In-Yong; Risticevic, Sanja; Pawliszyn, Janusz

2012-02-24

Air in a room infested by Cimex lectularius L. (Hemiptera: Cimicidae) was sampled simultaneously by three different sampling devices including solid phase microextraction (SPME) fiber coatings, thin film microextraction (TFME) devices, and needle trap devices (NTDs) and then analyzed by gas chromatography-mass spectrometry (GC-MS). The main focus of this study was to fully characterize indoor air by identifying compounds extracted by three different microextraction formats and, therefore, perform both the device comparison and more complete characterization of C. lectularius pheromone. The NTD technique was capable of extracting both (E)-2-hexenal and (E)-2-octenal, which were previously identified as alarm pheromones of bedbugs, and superior NTD recoveries for these two components allowed reliable identification based on mass spectral library searching and linear temperature programmed retention index (LTPRI) technique. While the use of DVB/CAR/PDMS SPME fiber coatings provided complementary sample fingerprinting and profiling results, TFME sampling devices provided discriminative extraction coverage toward highly volatile analytes. In addition to two alarm pheromones, relative abundances of all other analytes were recorded for all three devices and aligned across all examined samples, namely, highly infested area, less infested area, and control samples which were characterized by different bedbug populations. The results presented in the current study illustrate comprehensive characterization of infested indoor air samples through the use of three different non-invasive SPME formats and identification of novel components comprising C. lectularius pheromone, therefore, promising future alternatives for use of potential synthetic pheromones for detection of infestations. Copyright © 2011 Elsevier B.V. All rights reserved.

Combination of solvent extractants for dispersive liquid-liquid microextraction of fungicides from water and fruit samples by liquid chromatography with tandem mass spectrometry.

PubMed

Pastor-Belda, Marta; Garrido, Isabel; Campillo, Natalia; Viñas, Pilar; Hellín, Pilar; Flores, Pilar; Fenoll, José

2017-10-15

A multiresidue method was developed to determine twenty-five fungicides belonging to three different chemical families, oxazoles, strobilurins and triazoles, in water and fruit samples, using dispersive liquid-liquid microextraction (DLLME) and liquid chromatography/tandem mass spectrometry (LC-MS 2 ). Solid-liquid extraction with acetonitrile was used for the analysis in fruits, the extract being used as dispersant solvent in DLLME. Since some of the analytes showed high affinity for chloroform and the others were more efficiently extracted with undecanol, a mixture of both solvents was used as extractant in DLLME. After evaporation of CHCl 3 , the enriched phase was analyzed. Enrichment factors in the 23-119 and 12-60 ranges were obtained for waters and fruits, respectively. The approach was most sensitive for metominostrobin with limits of quantification of 1ngL -1 and 5ngkg -1 in waters and fruits, respectively, while a similar sensitivity was attained for tebuconazole in fruits. Recoveries of the fungicides varied between 86 and 116%. Copyright © 2017 Elsevier Ltd. All rights reserved.

A quantitative headspace-solid-phase microextraction-gas chromatography-flame ionization detector method to analyze short chain free fatty acids in rat feces.

PubMed

Fiorini, Dennis; Boarelli, Maria Chiara; Gabbianelli, Rosita; Ballini, Roberto; Pacetti, Deborah

2016-09-01

This study sought to develop and validate a quantitative method to analyze short chain free fatty acids (SCFAs) in rat feces by solid-phase microextraction and gas chromatography (SPME-GC) using the salt mixture ammonium sulfate and sodium dihydrogen phosphate as salting out agent. Conditioning and extraction time, linearity, limits of detection and quantification, repeatability, and recovery were evaluated. The proposed method allows quantification with improved sensitivity as compared with other methods exploiting SPME-GC. The method has been applied to analyze rat fecal samples, quantifying acetic, propionic, isobutyric, butyric, isopentanoic, pentanoic, and hexanoic acids. Copyright © 2016 Elsevier Inc. All rights reserved.

Rapid determination of some psychotropic drugs in complex matrices by tandem dispersive liquid-liquid microextraction followed by high performance liquid chromatography.

PubMed

Asghari, Alireza; Fahimi, Ebrahim; Bazregar, Mohammad; Rajabi, Maryam; Boutorabi, Leila

2017-05-01

Simple and rapid determinations of some psychotropic drugs in some pharmaceutical wastewater and human plasma samples were successfully accomplished via the tandem dispersive liquid-liquid microextraction combined with high performance liquid chromatography-ultraviolet detection (TDLLME-HPLC-UV). TDLLME of the three psychotropic drugs clozapine, chlorpromazine, and thioridazine was easily performed through two consecutive dispersive liquid-liquid microextractions. By performing this convenient method, proper sample preconcentrations and clean-ups were achieved in just about 7min. In order to achieve the best extraction efficiency, the effective parameters involved were optimized. The optimal experimental conditions consisted of 100μL of CCl 4 (as the extraction organic solvent), and the pH values of 13 and 2 for the donor and acceptor phases, respectively. Under these optimum experimental conditions, the proposed TDLLME-HPLC-UV technique provided a good linearity in the range of 5-3000ngmL -1 for the three psychotropic drugs with the correlation of determinations (R 2 s) higher than 0.996. The limits of quantification (LOQs) and limits of detection (LODs) obtained were 5.0ngmL -1 and 1.0-1.5ngmL -1 , respectively. Also the proper enrichment factors (EFs) of 96, 99, and 88 for clozapine, chlorpromazine, and thioridazine, respectively, and good extraction repeatabilities (relative standard deviations below 9.3%, n=5) were obtained. Copyright © 2017 Elsevier B.V. All rights reserved.

Application of liquid-liquid-liquid microextraction and high-performance liquid chromatography for the determination of alkylphenols and bisphenol-A in water.

PubMed

Lin, Che-Yi; Fuh, Ming-Ren; Huang, Shang-Da

2011-02-01

A method termed liquid-liquid-liquid microextraction (LLLME) was utilized to extract 4-t-butylphenol, 4-t-octylphenol, 4-n-nonylphenol, and bisphenol-A from water. The extracted target analytes were separated and quantified by high-performance liquid chromatography using a fluorescence detector. In LLLME, the donor phase (i.e. water sample) was made weakly acidic by adding monobasic potassium phosphate (KH(2) PO(4)); the organic phase adopted was 4-chlorotoluene; the acceptor phase (i.e. enriched extract) was 0.2 M tetraethylammonium hydroxide dissolved in ethylene glycol. This study solves a problem associated with the surface activity of long-chain alkylphenolate ions, permitting LLLME to extract long-chain alkylphenols. Experimental conditions such as acceptor phase composition, organic phase identity, acceptor phase volume, sample agitation, extraction time, and salt addition were optimized. The relative standard deviation (RSD, 2.0-5.8%), coefficient of determination (r(2) 0.9977-0.9999), and detection limit (0.017-0.0048 ng/mL) of the proposed method were achieved under the selected optimized conditions. The method was successfully applied to analyses of lake and tap water samples, and the relative recoveries of target analytes from the spiked lake and tap water samples were 92.8-106.3 and 93.6-105.6%, respectively. The results obtained with the proposed method confirm this microextraction technique to be reliable for the monitoring of alkylphenols and bisphenol-A in water samples. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gas chromatographic determination of polycyclic aromatic hydrocarbons in water and smoked rice samples after solid-phase microextraction using multiwalled carbon nanotube loaded hollow fiber.

PubMed

Matin, Amir Abbas; Biparva, Pourya; Gheshlaghi, Mohammad

2014-12-29

A novel solid-phase microextraction fiber was prepared based on multiwalled carbon nanotubes (MWCNTs) loaded on hollow fiber membrane pores. Stainless steel wire was used as unbreakable support. The major advantages of the proposed fiber are its (a) high reproducibility due to the uniform structure of the hollow fiber membranes, (b) high extraction capacity related to the porous structure of the hollow fiber and outstanding adsorptive characteristics of MWCNTs. The proposed fiber was applied for the microextraction of five representative polycyclic aromatic hydrocarbons (PAHs) from aqueous media (river and hubble-bubble water) and smoked rice samples followed by gas chromatographic determination. Analytical merits of the method, including high correlation coefficients [(0.9963-0.9992) and (0.9982-0.9999)] and low detection limits [(9.0-13.0ngL(-1)) and (40.0-150.0ngkg(-1))] for water and rice samples, respectively, made the proposed method suitable for the ultra-trace determination of PAHs. Copyright © 2014 Elsevier B.V. All rights reserved.

Preconcentration of aqueous dyes through phase-transfer liquid-phase microextraction with a room-temperature ionic liquid.

PubMed

Chen, Hsiu-Liang; Chang, Shuo-Kai; Lee, Chia-Ying; Chuang, Li-Lin; Wei, Guor-Tzo

2012-09-12

In this study, we employed the room-temperature ionic liquid [bmim][PF(6)] as both ion-pair agent and an extractant in the phase-transfer liquid-phase microextraction (PTLPME) of aqueous dyes. In the PTLPME method, a dye solution was added to the extraction solution, comprising a small amount of [bmim][PF(6)] in a relatively large amount of CH(2)Cl(2), which serves as the disperser solvent to an extraction solution. Following extraction, CH(2)Cl(2) was evaporated from the extractant, resulting in the extracted dyes being concentrated in a small volume of the ionic liquid phase to increase the enrichment factor. The enrichment factors of for the dye Methylene Blue, Neutral Red, and Methyl Red were approximately 500, 550 and 400, respectively; their detection limits were 0.014, 0.43, and 0.02 μg L(-1), respectively, with relative standard deviations of 4.72%, 4.20%, and 6.10%, respectively. Copyright © 2012 Elsevier B.V. All rights reserved.

Simultaneous Determination of Parathion, Malathion, Diazinon, and Pirimiphos Methyl in Dried Medicinal Plants Using Solid-Phase Microextraction Fibre Coated with Single-Walled Carbon Nanotubes

PubMed Central

Ahmadkhaniha, Reza; Samadi, Nasrin; Salimi, Mona; Sarkhail, Parisa; Rastkari, Noushin

2012-01-01

A reliable and sensitive headspace solid-phase microextraction gas chromatography-mass spectrometry method for simultaneous determination of different organophosphorus pesticides in dried medicinal plant samples is described. The analytes were extracted by single-walled carbon nanotubes as a new solid-phase microextraction adsorbent. The developed method showed good performance. For diazinon and pirimiphos methyl calibration, curves were linear (r 2 ≥ 0.993) over the concentration ranges from 1.5 to 300 ng g−1, and the limit of detection at signal-to-noise ratio of 3 was 0.3 ng g−1. For parathion and malathion, the linear range and limit of detection were 2.5–300 (r 2 ≥ 0.991) and 0.5 ng g−1, respectively. In addition, a comparative study between the single-walled carbon nanotubes and a commercial polydimethylsiloxane fibre for the determination of target analytes was carried out. Single-walled carbon nanotubes fibre showed higher extraction capacity, better thermal stability (over 350°C), and longer lifespan (over 250 times) than the commercial polydimethylsiloxane fibre. The developed method was successfully applied to determine target organophosphorus pesticides in real samples. PMID:22645439

Gas chromatographic detection of some nitro explosive compounds in soil samples after solid-phase microextraction with carbon ceramic copper nanoparticle fibers.

PubMed

Farhadi, Khalil; Bochani, Shayesteh; Hatami, Mehdi; Molaei, Rahim; Pirkharrati, Hossein

2014-07-01

In this research, a new solid-phase microextraction fiber based on carbon ceramic composites with copper nanoparticles followed by gas chromatography with flame ionization detection was applied for the extraction and determination of some nitro explosive compounds in soil samples. The proposed method provides an overview of trends related to synthesis of solid-phase microextraction sorbents and their applications in preconcentration and determination of nitro explosives. The sorbents were prepared by mixing of copper nanoparticles with a ceramic composite produced by mixture of methyltrimethoxysilane, graphite, methanol, and hydrochloric acid. The prepared sorbents were coated on copper wires by dip-coating method. The prepared nanocomposites were evaluated statistically and provided better limits of detection than the pure carbon ceramic. The limit of detection of the proposed method was 0.6 μg/g with a linear response over the concentration range of 2-160 μg/g and square of correlation coefficient >0.992. The new proposed fiber has been demonstrated to be a suitable, inexpensive, and sensitive candidate for extraction of nitro explosive compounds in contaminated soil samples. The constructed fiber can be used more than 100 times without the need for surface generation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rapid Screening of Volatile Organic Compounds from Aframomum danielli Seeds Using Headspace Solid Phase Microextraction Coupled to Gas Chromatography Mass Spectrometry

PubMed Central

Njobeh, Patrick B.; Gbashi, Sefater; Adegoke, Gabriel O.; Dubery, Ian A.

2018-01-01

Volatile organic compounds (VOCs) derived from plants have been used in the fragrance industry since time immemorial. Herein we report on the rapid screening of VOCs from seeds of ripe Aframomum danielli (family, Zingiberaceae) using a polydimethylsiloxane fibre headspace solid phase microextraction coupled to a gas chromatography mass spectrometry (SPME-GC/MS) instrument. Portions of 0.25, 0.35, and 0.50 g of ground sample were weighed and extraction of volatile organic compounds (VOCs) was achieved using a 100 μm polydimethylsiloxane solid phase microextraction (PDMS SPME) fibre, with the equilibrium time of 40 minutes and extraction temperature of 50°C; the following compounds with their respective relative abundances were obtained as the top ten most abundant and annotated ones using NIST, Wiley, and Fragrances Libraries: eucalyptol (58%); β-pinene (22%); α-pinene (7.5%); α-terpineol (4%), α-terpinyl acetate (2%); α-bergamotene (1%); pinocarveol (0.39%); α-copaene (0.35%); caryophyllene (0.34); and β-bisabolene (0.31%). These compounds have been reported elsewhere in the literature and listed in the Fragrances Library, incorporated into the Saturn QP2020 GCMS Solution® software used for their analysis. PMID:29849643

Characterization of the Key Aroma Compounds in Proso Millet Wine Using Headspace Solid-Phase Microextraction and Gas Chromatography-Mass Spectrometry.

PubMed

Liu, Jingke; Zhao, Wei; Li, Shaohui; Zhang, Aixia; Zhang, Yuzong; Liu, Songyan

2018-02-20

The volatile compounds in proso millet wine were extracted by headspace solid-phase microextraction (85 μm polyacrylate (PA), 100 μm polydimethylsiloxane (PDMS), 75 μm Carboxen (CAR)/PDMS, and 50/30 μm divinylbenzene (DVB)/CAR/PDMS fibers), and analyzed using gas chromatography-mass spectrometry; the odor characteristics and intensities were analyzed by the odor activity value (OAV). Different sample preparation factors were used to optimize this method: sample amount, extraction time, extraction temperature, and content of NaCl. A total of 64 volatile compounds were identified from the wine sample, including 14 esters, seven alcohols, five aldehydes, five ketones, 12 benzene derivatives, 12 hydrocarbons, two terpenes, three phenols, two acids, and two heterocycles. Ethyl benzeneacetate, phenylethyl alcohol, and benzaldehyde were the main volatile compounds found in the samples. According to their OAVs, 14 volatile compounds were determined to be odor-active compounds (OAV > 1), and benzaldehyde, benzeneacetaldehyde, 1-methyl-naphthalene, 2-methyl-naphthalene, and biphenyl were the prominent odor-active compounds (OAV > 50), having a high OAV. Principal component analysis (PCA) showed the difference of distribution of the 64 volatile compounds and 14 odor-active compounds with four solid-phase microextraction (SPME) fibers.

Preparation and application of a polythiophene solid-phase microextraction fiber for the determination of endocrine-disruptor pesticides in well waters.

PubMed

Pelit, Levent; Dizdaş, Tuğberk Nail

2013-10-01

A robust solid-phase microextraction fiber was fabricated by electropolymerization of thiophene on a stainless steel wire. This fiber was applied for the determination of endocrine-disruptor pesticides, namely, chlorpyrifos, penconazole, procymidone, bromopropylate, and λ-cyhalothrin in well waters by a headspace solid-phase microextraction procedure. Operational parameters, namely, pH, sample volume, adsorption temperature and time, desorption temperature, stirring rate, and salt amount were optimized as 7.0, 8 mL, 70°C and 20 min, 250°C, 600 rpm, and 0.3 g/mL, respectively. The separation power of GC was coupled with the excellent sensitivity of the developed fiber enabling us to determine pesticide mixtures simultaneously in a ng/mL range. The LOD was in the range of 0.02-0.64 ng/mL. The method was successfully applied for the selective and sensitive determination of target pesticides in well water samples with acceptable recovery values (92-110%). The polythiophene fiber gives satisfactory results compared with commercial fibers. Commonly used pesticides with different polarities were chosen as representative compounds to search the applicability of the fiber for well water analysis collected from vineyards. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Application of a novel cold activated carbon fiber-solid phase microextraction for analysis of organochlorine pesticides in soil.

PubMed

Chai, Xiaolan; Jia, Jinping; Sun, Tonghua; Wang, Yalin; Liao, Liyan

2007-08-01

A novel and simple analytical procedure using cold activated carbon fiber-solid phase microextraction (CACF-SPME) was applied to determine organochlorine pesticides (OCs) in soil samples. The pesticides in this study consist of alpha -, beta -, gamma -, and delta -hexachlorocyclohexane (HCH). By heating the sample while cooling the fiber, the developed method not only provides better performance in terms of sensitivity, linearity and recovery but also offers shorter adsorption procedure than that of traditional headspace-solid phase microextraction (HS-SPME). The experimental conditions such as the amount of water, adsorption time and adsorption temperature were optimized. Matrix effects were investigated with different types of soils. We concluded that using the standard addition method was required for quantification purposes. The limits of detection obtained using the proposed method range from 0.01 to 0.05 ng/g, and the recoveries for CACF-SPME are in the range of 80.01% to 89.68% with relative standard deviation (RSDs) better than 8.60%. The proposed method was further applied to determine OCs in real agricultural soil. The results are in good agreement with those obtained using traditional ultrasonic extraction. The research demonstrates the suitability of the CACF-SPME for the analysis of OCs in soil.

A novel poly(3,4-ethylenedioxythiophene)-ionic liquid composite coating for the headspace solid-phase microextraction and gas chromatography determination of several alcohols in soft drinks.

PubMed

Wu, Mian; Zhang, Haibo; Zhao, Faqiong; Zeng, Baizhao

2014-11-19

A novel poly(3,4-ethylenedioxythiophene)-ionic liquid (i.e., 1-hydroxyethyl-3-methyl imidazolium-bis[(trifluoromethyl)sulfonyl]imide) composite film was electrodeposited on a Pt wire for headspace solid-phase microextraction. The film showed nodular structure and had large specific surface. In addition, it displayed high thermal stability (up to 300°C) and durable property (could be used for more than 200 times). Coupled with gas chromatography-flame ionization detection, the resulting fiber was applied to the headspace solid-phase microextraction and determination of several alcohols (i.e., linalool, nonanol, terpineol, geraniol, decanol and dodecanol). It presented higher extraction capability in comparison with the poly(3,4-ethylenedioxythiophene) and commercial polydimethylsiloxane/divinylbenzene fiber. Under the optimized conditions, the linear ranges exceeded three magnitudes with correlation coefficients above 0.9952 and the low limits of detection were 34.2-81.3ng L(-1). For different alcohols the repeatabilities (defined as RSD) were <5.8% and <7.8% for single fiber (n=5) and fiber-to-fiber (n=4), respectively. The proposed method was applied to the determination of these alcohols in real samples with acceptable recoveries from 81.1% to 106.6%. Copyright © 2014 Elsevier B.V. All rights reserved.

Graphene oxide decorated with silver nanoparticles as a coating on a stainless-steel fiber for solid-phase microextraction.

PubMed

Wang, Licheng; Hou, Xiudan; Li, Jubai; Liu, Shujuan; Guo, Yong

2015-07-01

A novel graphene oxide decorated with silver nanoparticles coating on a stainless-steel fiber for solid-phase microextraction was prepared. Scanning electron microscopy and X-ray photoelectron spectroscopy were used to characterize the coating surface and showed that silver nanoparticles were dispersed on the wrinkled graphene oxide surface. Coupled to gas chromatography with flame ionization detection, the extraction abilities of the fiber for polycyclic aromatic hydrocarbons were examined in the headspace solid-phase microextraction mode. The extraction parameters including adsorption time, adsorption temperature, salt concentration, desorption time and desorption temperature were investigated. Under the optimized condition, wide linearity with low limits of detection from 2 to 10 ng/L was obtained. The relative standard deviations for single-fiber repeatability and fiber-to-fiber reproducibility were less than 10.6 and 17.5%, respectively. The enrichment factors were from 1712.5 to 4503.7, showing the fiber has good extraction abilities. Moreover, the fiber exhibited a good stability and could be reused for more than 120 times. The established method was also applied for determination of polycyclic aromatic hydrocarbons in two real water samples and the recoveries of analytes ranged from 84.4-116.3% with relative standard deviations less than 16.2%. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A paper-based analytical device for the determination of hydrogen sulfide in fuel oils based on headspace liquid-phase microextraction and cyclic voltammetry.

PubMed

Nechaeva, Daria; Shishov, Andrey; Ermakov, Sergey; Bulatov, Andrey

2018-06-01

An easily performed miniaturized, cheap, selective and sensitive procedure for the determination of H 2 S in fuel oil samples based on a headspace liquid-phase microextraction followed by a cyclic voltammetry detection using a paper-based analytical device (PAD) was developed. A modified wax dipping method was applied to fabricate the PAD. The PAD included hydrophobic zones of sample and supporting electrolyte connecting by hydrophilic channel. The zones of sample and supporting electrolyte were connected with nickel working, platinum auxiliary and Ag/AgCl reference electrodes. The analytical procedure included separation of H 2 S from fuel oil sample based on the headspace liquid-phase microextraction in alkaline solution. Then, sulfide ions solution obtained and supporting electrolyte were dropped on the zones followed by analyte detection at + 0.45 V. Under the optimized conditions, H 2 S concentration in the range from 2 to 20 mg kg -1 had a good linear relation with the peak current. The limit of detection (3σ) was 0.6 mg kg -1 . The procedure was successfully applied to the analysis of fuel oil samples. Copyright © 2018 Elsevier B.V. All rights reserved.

Graphene/dodecanol floating solidification microextraction for the preconcentration of trace levels of cinnamic acid derivatives in traditional Chinese medicines.

PubMed

Hu, Shuang; Yang, Xiao; Xue, Jiao; Chen, Xuan; Bai, Xiao-Hong; Yu, Zhi-Hui

2017-07-01

A novel graphene/dodecanol floating solidification microextraction followed by HPLC with diode-array detection has been developed to extract trace levels of four cinnamic acid derivatives in traditional Chinese medicines. Several parameters affecting the performance were investigated and optimized. Also, possible microextraction mechanism was analyzed and discussed. Under the optimum conditions (amount of graphene in dodecanol: 0.25 mg/mL; volume of extraction phase: 70 μL; pH of sample phase: 3; extraction time: 30   min; stirring rate: 1000 rpm; salt amount: 26.5% NaCl; volume of sample phase: 10 mL, and without dispersant addition), the enrichment factors of four cinnamic acid derivatives ranged from 26 to 112, the linear ranges were 1.0 × 10 -2 -10.0 μg/mL for caffeic acid, 1.3 × 10 -3 -1.9 μg/mL for p-hydroxycinnamic acid, 2.8 × 10 -3 -4.1 μg/mL for ferulic acid, and 2.7 × 10 -3 -4.1 μg/mL for cinnamic acid, with r 2 ≥ 0.9993. The detection limits were found to be in the range of 0.1-1.0 ng/mL, and satisfactory recoveries (92.5-111.2%) and precisions (RSDs 1.1-9.5%) were also achieved. The results showed that the approach is simple, effective and sensitive for the preconcentration and determination of trace levels of cinnamic acid derivatives in Chinese medicines. The proposed method was compared with conventional dodecanol floating solidification microextraction and other extraction methods. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Water-contained surfactant-based vortex-assisted microextraction method combined with liquid chromatography for determination of synthetic antioxidants from edible oil.

PubMed

Amlashi, Nadiya Ekbatani; Hadjmohammadi, Mohammad Reza; Nazari, Seyed Saman Seyed Jafar

2014-09-26

For the first time, a novel water-contained surfactant-based vortex-assisted microextraction method (WSVAME) was developed for the extraction of two synthetic antioxidants (t-butyl hydroquinone (TBHQ) and butylated hydroxyanisole (BHA)) from edible oil samples. The novel microextraction method is based on the injection of an aqueous solution of non-ionic surfactant, Brij-35, into the oil sample in a conical bottom glass tube to form a cloudy solution. Vortex mixing was applied to accelerate the dispersion process. After extraction and phase separation by centrifugation, the lower sediment phase was directly analyzed by HPLC. The effects of the four experimental parameters including volume and concentration of extraction solvent (aqueous solution of Brij-35), percentage of acetic acid added to the oil sample and vortex time on the extraction efficiency were studied with a full factorial design. The central composite design and multiple linear regression method were applied for the construction of the best polynomial model based on experimental recoveries. The proposed method showed good linearity within the range of 0.200-200 μg mL(-1), the square of correlation coefficient higher than 0.999 and appropriate limit of detection (0.026 and 0.020 μg mL(-1) for TBHQ and BHA, respectively), while the precision for inner-day was ≤ 3.0 (n=5) and it was ≤ 3.80 (n=5) for inter-day assay. Under the optimal condition (30 μL of 0.10 mol L(-1) Brij-35 solution as extraction solvent and vortex time 1 min), the method was successfully applied for determination of TBHQ and BHA in different commercial edible oil samples. The recoveries in all cases were above 95%, with relative standard deviations below 5%. This approach is considered as a simple, sensitive and environmentally friendly method because of biodegradability of the extraction phase and no use of organic solvent in the extraction procedure. Copyright © 2014 Elsevier B.V. All rights reserved.

Application of Solid Phase Microextraction with Gas Chromatography-Mass Spectrometry as a Rapid, Reliable, and Safe Method for Field Sampling and Analysis of Chemical Warfare Agent Precursors

DTIC Science & Technology

2005-03-01

in hair samples with analysis by GC-MS [41,42]. The research discussed here examined a polydimethylsiloxane polymer with 10% activated charcoal (PDMS...Field Sampling and Analysis of Chemical Warfare Agent Precursors” Name of Candidate: LT Douglas Parrish Doctor of Philosophy, Environmental...Microextraction with Gas Chromatography-Mass Spectrometry as a Rapid, Reliable, and Safe Method for Field Sampling and Analysis of Chemical Warfare

Development of a novel ultrasound-assisted headspace liquid-phase microextraction and its application to the analysis of chlorophenols in real aqueous samples.

PubMed

Xu, Hui; Liao, Ying; Yao, Jinrong

2007-10-05

A new sample pretreatment technique, ultrasound-assisted headspace liquid-phase microextraction was developed as mentioned in this paper. In the technique, the volatile analytes were headspace extracted into a small drop of solvent, which suspended on the bottom of a cone-shaped PCR tube instead of the needle tip of a microsyringe. More solvent could be suspended in the PCR tube than microsyringe due to the larger interfacial tension, thus the analysis sensitivity was significantly improved with the increase of the extractant volume. Moreover, ultrasound-assisted extraction and independent controlling temperature of the extractant and the sample were performed to enhance the extraction efficiency. Following the extraction, the solvent-loaded sample was analyzed by high-performance liquid chromatography. Chlorophenols (2-chlorophenol, 2,4-dichlorophenol and 2,6-dichlorophenol) were chosen as model analytes to investigate the feasibility of the method. The experimental conditions related to the extraction efficiency were systematically studied. Under the optimum experimental conditions, the detection limit (S/N=3), intra- and inter-day RSD were 6 ng mL(-1), 4.6%, 3.9% for 2-chlorophenol, 12 ng mL(-1), 2.4%, 8.8% for 2,4-dichlorophenol and 23 ng mL(-1), 3.3%, 5.3% for 2,6-dichlorophenol, respectively. The proposed method was successfully applied to determine chlorophenols in real aqueous samples. Good recoveries ranging from 84.6% to 100.7% were obtained. In addition, the extraction efficiency of our method and the conventional headspace liquid-phase microextraction were compared; the extraction efficiency of the former was about 21 times higher than that of the latter. The results demonstrated that the proposed method is a promising sample pretreatment approach, its advantages over the conventional headspace liquid-phase microextraction include simple setup, ease of operation, rapidness, sensitivity, precision and no cross-contamination. The method is very suitable for the analysis of trace volatile and semivolatile pollutants in real aqueous sample.

Solventless and solvent-minimized sample preparation techniques for determining currently used pesticides in water samples: a review.

PubMed

Tankiewicz, Maciej; Fenik, Jolanta; Biziuk, Marek

2011-10-30

The intensification of agriculture means that increasing amounts of toxic organic and inorganic compounds are entering the environment. The pesticides generally applied nowadays are regarded as some of the most dangerous contaminants of the environment. Their presence in the environment, especially in water, is hazardous because they cause human beings to become more susceptible to disease. For these reasons, it is essential to monitor pesticide residues in the environment with the aid of all accessible analytical methods. The analysis of samples for the presence of pesticides is problematic, because of the laborious and time-consuming operations involved in preparing samples for analysis, which themselves may be a source of additional contaminations and errors. To date, it has been standard practice to use large quantities of organic solvents in the sample preparation process; but as these solvents are themselves hazardous, solventless and solvent-minimized techniques are coming into use. This paper discusses the most commonly used over the last 15 years sample preparation techniques for monitoring organophosphorus and organonitrogen pesticides residue in water samples. Furthermore, a significant trend in sample preparation, in accordance with the principles of 'Green Chemistry' is the simplification, miniaturization and automation of analytical techniques. In view of this aspect, several novel techniques are being developed in order to reduce the analysis step, increase the sample throughput and to improve the quality and the sensitivity of analytical methods. The paper describes extraction techniques requiring the use of solvents - liquid-liquid extraction (LLE) and its modifications, membrane extraction techniques, hollow fibre-protected two-phase solvent microextraction, liquid phase microextraction based on the solidification of a floating organic drop (LPME-SFO), solid-phase extraction (SPE) and single-drop microextraction (SDME) - as well as solvent-free techniques - solid phase microextraction (SPME) and stir bar sorptive extraction (SBSE). The advantages and drawbacks of these techniques are also discussed, and some solutions to their limitations are proposed. Copyright © 2011 Elsevier B.V. All rights reserved.

Determination of diflubenzuron and chlorbenzuron in fruits by combining acetonitrile-based extraction with dispersive liquid-liquid microextraction followed by high-performance liquid chromatography.

PubMed

Ruan, Chunqiang; Zhao, Xiang; Liu, Chenglan

2015-09-01

In this study, a simple and low-organic-solvent-consuming method combining an acetonitrile-partitioning extraction procedure followed by "quick, easy, cheap, effective, rugged and safe" cleanup with ionic-liquid-based dispersive liquid-liquid microextraction and high-performance liquid chromatography with diode array detection was developed for the determination of diflubenzuron and chlorbenzuron in grapes and pears. Ionic-liquid-based dispersive liquid-liquid microextraction was performed using the ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate as the extractive solvent and acetonitrile extract as the dispersive solvent. The main factors influencing the efficiency of the dispersive liquid-liquid microextraction were evaluated, including the extractive solvent type and volume and the dispersive solvent volume. The validation parameters indicated the suitability of the method for routine analyses of benzoylurea insecticides in a large number of samples. The relative recoveries at three spiked levels ranged between 98.6 and 109.3% with relative standard deviations of less than 5.2%. The limit of detection was 0.005 mg/kg for the two insecticides. The proposed method was successfully used for the rapid determination of diflubenzuron and chlorbenzuron residues in real fruit samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of tramadol by dispersive liquid-liquid microextraction combined with GC-MS.

PubMed

Habibollahi, Saeed; Tavakkoli, Nahid; Nasirian, Vahid; Khani, Hossein

2015-01-01

Dispersive liquid-liquid microextraction (DLLME) coupled with gas chromatography-mass spectrometry (GC-MS) has been developed for preconcentration and determination of tramadol, ((±)-cis-2-[(dimethylamino)methyl]-1-(3-methoxyphenyl)cyclohexanol-HCl), in aqueous and biological samples (urine, blood). DLLME is a simple, rapid and efficient method for determination of drugs in aqueous samples. Efficient factors on the DLLME process has defined and optimized for extraction of tramadol including type of extraction and disperser solvents and their volumes, pH of donor phase, time of extraction and ionic strength of donor phase. Based on the results of this study, under optimal conditions and by using 2-nitro phenol as internal standard, tramadol was determined by GC-MS, and the figures of merit of this work were evaluated. The enrichment factor, relative recovery and limit of detection were obtained 420, 99.2% and 0.08 µg L(-1), respectively. The linear range was between 0.26 and 220.00 µg L(-1) (R(2) = 0.9970). The relative standard deviation for 50.00 µg L(-1) of tramadol in aqueous samples by using 2-nitro phenol as IS was 3.6% (n = 7). Finally, the performance of DLLME was evaluated for analysis of tramadol in urine and blood. Published by Oxford University Press 2014. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Development of a dispersive liquid-liquid microextraction method using a lighter-than-water ionic liquid for the analysis of polycyclic aromatic hydrocarbons in water.

PubMed

Medina, Giselle S; Reta, Mario

2016-11-01

A dispersive liquid-liquid microextraction method using a lighter-than-water phosphonium-based ionic liquid for the extraction of 16 polycyclic aromatic hydrocarbons from water samples has been developed. The extracted compounds were analyzed by liquid chromatography coupled to fluorescence/diode array detectors. The effects of several experimental parameters on the extraction efficiency, such as type and volume of ionic liquid and disperser solvent, type and concentration of salt in the aqueous phase and extraction time, were investigated and optimized. Three phosphonium-based ionic liquids were assayed, obtaining larger extraction efficiencies when trihexyl-(tetradecyl)phosphonium bromide was used. The optimized methodology requires a few microliters of a lighter-than-water phosphonium-based ionic liquid, which allows an easy separation of the extraction solvent phase. The obtained limits of detection were between 0.02 and 0.56 μg/L, enrichment factors between 109 and 228, recoveries between 60 and 108%, trueness between 0.4 and 9.9% and reproducibility values between 3 and 12% were obtained. These figures of merit combined with the simplicity, rapidity and low cost of the analytical methodology indicate that this is a viable and convenient alternative to the methods reported in the literature. The developed method was used to analyze polycyclic aromatic hydrocarbons in river water samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Combination of saponification and dispersive liquid-liquid microextraction for the determination of tocopherols and tocotrienols in cereals by reversed-phase high-performance liquid chromatography.

PubMed

Shammugasamy, Balakrishnan; Ramakrishnan, Yogeshini; Ghazali, Hasanah M; Muhammad, Kharidah

2013-07-26

A simple sample preparation technique coupled with reversed-phase high-performance liquid chromatography was developed for the determination of tocopherols and tocotrienols in cereals. The sample preparation procedure involved a small-scale hydrolysis of 0.5g cereal sample by saponification, followed by the extraction and concentration of tocopherols and tocotrienols from saponified extract using dispersive liquid-liquid microextraction (DLLME). Parameters affecting the DLLME performance were optimized to achieve the highest extraction efficiency and the performance of the developed DLLME method was evaluated. Good linearity was observed over the range assayed (0.031-4.0μg/mL) with regression coefficients greater than 0.9989 for all tocopherols and tocotrienols. Limits of detection and enrichment factors ranged from 0.01 to 0.11μg/mL and 50 to 73, respectively. Intra- and inter-day precision were lower than 8.9% and the recoveries were around 85.5-116.6% for all tocopherols and tocotrienols. The developed DLLME method was successfully applied to cereals: rice, barley, oat, wheat, corn and millet. This new sample preparation approach represents an inexpensive, rapid, simple and precise sample cleanup and concentration method for the determination of tocopherols and tocotrienols in cereals. Copyright © 2013 Elsevier B.V. All rights reserved.

Enantioselective determination of the organochlorine pesticide bromocyclen in spiked fish tissue using solid-phase microextraction coupled to gas chromatography with ECD and ICP-MS detection.

PubMed

Fidalgo-Used, Natalia; Montes-Bayón, Maria; Blanco-González, Elisa; Sanz-Medel, Alfredo

2008-05-15

A method for enantioselective determination of bromocyclen enantiomers in fish tissue has been developed. The enantiomers were resolved by capillary gas chromatography (GC) using a commercial chiral column (CP-Chirasil-Dex CB) and a temperature program from 50 degrees C (held for 1 min), raised to 140 degrees C at 40 degrees C min(-1) and then raised at 0.2 degrees C min(-1) to 155 degrees C. This enantioselective gas chromatographic separation was combined with a clean-up/enrichment procedure based on solid-phase microextraction (SPME). Under SPME optimized conditions, precision, linearity range and detection limits of the developed SPME-enantioselective GC procedure were evaluated and compared using two different detection systems: a classical electron-capture detection (ECD) and an element specific detection using inductively coupled plasma mass spectrometry (ICP-MS). The SPME-GC-ECD method exhibited an excellent sensitivity, with detection limits of 0.2 ng L(-1) for each enantiomer of bromocyclen. Although ICP-MS offered poorer detection limits (7 ng L(-1) as Br, equivalent to 36 ng L(-1) of each enantiomer) than conventional ECD detector, it proved to be clearly superior in terms of selectivity. The relative potential and performance of the two compared methods for real-life analysis has been illustrated by the determination of enantiomers of bromocyclen in spiked tissue extracts of trout.

Displacement-dispersive liquid-liquid microextraction based on solidification of floating organic drop of trace amounts of palladium in water and road dust samples prior to graphite furnace atomic absorption spectrometry determination.

PubMed

Ghanbarian, Maryam; Afzali, Daryoush; Mostafavi, Ali; Fathirad, Fariba

2013-01-01

A new displacement-dispersive liquid-liquid microextraction method based on the solidification of floating organic drop was developed for separation and preconcentration of Pd(ll) in road dust and aqueous samples. This method involves two steps of dispersive liquid-liquid microextraction based on solidification. In Step 1, Cu ions react with diethyldithiocarbamate (DDTC) to form Cu-DDTC complex, which is extracted by dispersive liquid-liquid microextraction based on a solidification procedure using 1-undecanol (extraction solvent) and ethanol (dispersive solvent). In Step 2, the extracted complex is first dispersed using ethanol in a sample solution containing Pd ions, then a dispersive liquid-liquid microextraction based on a solidification procedure is performed creating an organic drop. In this step, Pd(ll) replaces Cu(ll) from the pre-extracted Cu-DDTC complex and goes into the extraction solvent phase. Finally, the Pd(ll)-containing drop is introduced into a graphite furnace using a microsyringe, and Pd(ll) is determined using atomic absorption spectrometry. Several factors that influence the extraction efficiency of Pd and its subsequent determination, such as extraction and dispersive solvent type and volume, pH of sample solution, centrifugation time, and concentration of DDTC, are optimized.

Comparison between dispersive solid-phase and dispersive liquid-liquid microextraction combined with spectrophotometric determination of malachite green in water samples based on ultrasound-assisted and preconcentration under multi-variable experimental design optimization.

PubMed

Alipanahpour Dil, Ebrahim; Ghaedi, Mehrorang; Asfaram, Arash; Zare, Fahimeh; Mehrabi, Fatemeh; Sadeghfar, Fardin

2017-11-01

The ultrasound-assisted dispersive solid-phase microextraction (USA-DSPME) and the ultrasound-assisted dispersive liquid-liquid microextraction (USA-DLLME) developed for as an ultra preconcentration and/or technique for the determination of malachite green (MG) in water samples. Central composite design based on analysis of variance and desirability function guide finding best operational conditions and represent dependency of response to variables viz. volume of extraction, eluent and disperser solvent, pH, adsorbent mass and ultrasonication time has significant influence on methods efficiency. Optimum conditions was set for USA-DSPME as: 1mg CNTs/Zn:ZnO@Ni 2 P-NCs; 4min sonication time and 130μL eluent at pH 6.0. Meanwhile optimum point for USA-DLLME conditions were fixed at pH 6.0; 4min sonication time and 130, 650μL and 10mL of extraction solvent (CHCl 3 ), disperser solvent (ethanol) and sample volume, respectively. Under the above specified best operational conditions, the enrichment factors for the USA-DSPME and USA-DLLME were 88.89 and 147.30, respectively. The methods has linear response in the range of 20.0 to 4000.0ngmL -1 with the correlation coefficients (r) between 0.9980 to 0.9995, while its reasonable detection limits viz. 1.386 to 2.348ngmL -1 and good relative standard deviations varied from 1.1% to 2.8% (n=10) candidate this method for successful monitoring of analyte from various media. The relative recoveries of the MG dye from water samples at spiking level of 500ngmL -1 were in the range between 94.50% and 98.86%. The proposed methods has been successfully applied to the analysis of the MG dye in water samples, and a satisfactory result was obtained. Copyright © 2017. Published by Elsevier B.V.

Speciation and determination of ultra trace amounts of inorganic tellurium in environmental water samples by dispersive liquid-liquid microextraction and electrothermal atomic absorption spectrometry.

PubMed

Najafi, Nahid Mashkouri; Tavakoli, Hamed; Alizadeh, Reza; Seidi, Shahram

2010-06-18

A simple and powerful method has been developed for the rapid and selective determination of Te(IV) and Te(VI), employing dispersive liquid-liquid microextraction combined with electrothermal atomic absorption spectrometry using palladium as permanent modifier. Under acidic conditions pH 1, only Te(IV) can form a complex with ammonium pyrrolidine dithiocarbamate (APDC) and therefore be extracted into fine droplets of carbon tetrachloride (extraction solvent) which are dispersed with ethanol into the water sample solution. After centrifugation, Te(IV) was determined in the sedimented organic phase while Te(VI) remained in the aqueous phase. Total inorganic tellurium was determined after the reduction of the Te(VI) to Te(IV). Te(VI) was calculated as the difference between the measured total inorganic tellurium and Te(IV) content. The effective parameters for improving the efficiency of microextraction process were investigated by using experimental and central composite designs. Under optimal conditions the enrichment factor was 125 and the calibration graph was linear in the range of 0.015-1 ng mL(-1) with detection limit and characteristic mass of 0.004 ng mL(-1) and 0.033 pg, respectively. The relative standard deviation for 0.5 ng mL(-1) of tellurium measurement was 3.6% (n=6) at ash and atomization temperature, 900 and 2600 degrees C, respectively. The recoveries of spiked Te(IV) and Te(VI) to the environmental water samples were 89.6-101.3% and 96.6-99.1%, respectively. The accuracy is also evaluated by applying the proposed method to certified reference material (NIST SRM 1643e), for which the result was in a good agreement with the certified values reported for this CRM (95% confidence level). 2010 Elsevier B.V. All rights reserved.

Molecularly imprinted-solid phase extraction combined with simultaneous derivatization and dispersive liquid-liquid microextraction for selective extraction and preconcentration of methamphetamine and ecstasy from urine samples followed by gas chromatography.

PubMed

Djozan, Djavanshir; Farajzadeh, Mir Ali; Sorouraddin, Saeed Mohammad; Baheri, Tahmineh

2012-07-27

In this study, a developed technique was reported for extraction and pre-concentration of methamphetamine (MAMP) and 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) from urine samples using molecularly imprinted-solid phase extraction (MISPE) along with simultaneous derivatization and dispersive liquid-liquid microextraction (DLLME). Molecularly imprinted microspheres as sorbent in solid phase extraction (SPE) procedure were synthesized using precipitation polymerization with MAMP as the template. Aqueous solution of the target analytes was passed through MAMP-MIP cartridge and the adsorbed analytes were then eluted with methanol. The collected eluate was mixed with butylchloroformate which served as the derivatization reagent as well as the extraction solvent. The mixture was immediately injected into deionized water. After centrifugation, 1 μL of the settled organic phase was injected into gas chromatography-flame ionization detection (GC-FID) or gas chromatography-mass spectrometry (GC-MS). Various experimental parameters affecting the performance of both of the steps (MISPE and DLLME) were thoroughly investigated. The calibration graphs were linear in the ranges of 10-1500 ng mL(-1) (MAMP) and 50-1500 ng mL(-1) (MDMA), and the detection limits (LODs) were 2 and 18 ng mL(-1), respectively. The relative standard deviations (%RSDs) obtained for six repeated experiments (100 ng mL(-1) of each drug) were 5.1% and 6.8% for MAMP and MDMA, respectively. The relative recoveries obtained for the analytes in human urine samples, spiked with different levels of each drug, were within the range of 80-88%. Copyright © 2012 Elsevier B.V. All rights reserved.

Bar adsorptive microextraction technique - application for the determination of pharmaceuticals in real matrices.

PubMed

Almeida, Carlos; Ahmad, Samir M; Nogueira, José Manuel F

2017-03-01

In the present work, bar adsorptive microextraction using miniaturized devices (7.5 × 3.0 mm) coated with suitable sorbent phases, combined with microliquid desorption (100 μL) followed by high-performance liquid chromatography with diode array detection (BAμE-μLD/HPLC-DAD), is proposed for the determination of trace level of six pharmaceuticals (furosemide, mebeverine, ketoprofen, naproxen, diclofenac and mefenamic acid) in environmental water and urine matrices. By comparing ten distinct sorbent materials (five polymeric and five activated carbons), the polymer P5 proved to be the most suitable to achieve the best selectivity and efficiency. The solvent volume minimization in the liquid desorption stage demonstrated remarkable effectiveness, being more environmentally friendly, and simultaneously increased the microextraction enrichment factor two-fold. Assays performed through BAμE(P5, 0.9 mg)-μLD(100 μL)/HPLC-DAD on 25 mL of ultrapure water samples spiked at the 4.0 μg/L level yielded average recoveries ranging from 91.4% (furosemide) to 101.0% (ketoprofen) with good precision (RSD < 10.6%), under optimized experimental conditions. The analytical performance showed convenient detection limits (25.0 - 120.0 ng/L), good linear dynamic ranges (0.1 to 24.0 μg/L), appropriate determination coefficients (r 2 > 0.9983), and excellent repeatability through intraday (RSD < 10.4%)) and interday (RSD < 10.0%) assays. By using the standard addition methodology, the application of the present analytical approach on environmental waters and urine samples revealed the occurrence of trace levels of some pharmaceuticals. The solvent minimization during the back-extraction step associated with the miniaturization of BAμE devices proved to be a very promising analytical technology for static microextraction analysis. Graphical abstract BAμE operating under the floating sampling technology for the determination of pharmaceuticals in aqueous media.

Determination of N,N-dimethyltryptamine in beverages consumed in religious practices by headspace solid-phase microextraction followed by gas chromatography ion trap mass spectrometry.

PubMed

Gaujac, Alain; Dempster, Nicola; Navickiene, Sandro; Brandt, Simon D; de Andrade, Jailson Bittencourt

2013-03-15

A novel analytical approach combining solid-phase microextraction (SPME)/gas chromatography ion trap mass spectrometry (GC-IT-MS) was developed for the detection and quantification N,N-dimethyltryptamine (DMT), a powerful psychoactive indole alkaloid present in a variety of South American indigenous beverages, such as ayahuasca and vinho da jurema. These particular plant products, often used within a religious context, are increasingly consumed throughout the world following an expansion of religious groups and the availability of plant material over the Internet and high street shops. The method described in the present study included the use of SPME in headspace mode combined GC-IT-MS and included the optimization of the SPME procedure using multivariate techniques. The method was performed with a polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber in headspace mode (70 min at 60 °C) which resulted in good precision (RSD<8.6%) and accuracy values (71-109%). Detection and quantification limits obtained for DMT were 0.78 and 9.5 mg L(-1), respectively and good linearity (1.56-300 mg L(-1), r(2)=0.9975) was also observed. In addition, the proposed method showed good robustness and allowed for the minimization of sample manipulation. Five jurema beverage samples were prepared in the laboratory in order to study the impact of temperature, pH and ethanol on the ability to extract DMT into solution. The developed method was then applied to the analysis of twelve real ayahuasca and vinho da jurema samples, obtained from Brazilian religious groups, which revealed DMT concentration levels between 0.10 and 1.81 g L(-1). Copyright © 2013 Elsevier B.V. All rights reserved.

Development of magnetic dispersive solid phase extraction using toner powder as an efficient and economic sorbent in combination with dispersive liquid-liquid microextraction for extraction of some widely used pesticides in fruit juices.

PubMed

Farajzadeh, Mir Ali; Mohebbi, Ali

2018-01-12

In this study, for the first time, a magnetic dispersive solid phase extraction method using an easy-accessible, cheap, and efficient magnetic sorbent (toner powder) combined with dispersive liquid-liquid microextraction has been developed for the extraction and preconcentration of some widely used pesticides (diazinon, ametryn, chlorpyrifos, penconazole, oxadiazon, diniconazole, and fenazaquin) from fruit juices prior to their determination by gas chromatography-flame ionization detection. In this method, the magnetic sorbent is mixed with an appropriate dispersive solvent (methanol-water, 80:20, v/v) and then injected into an aqueous sample containing the analytes. By this action the analytes are rapidly adsorbed on the sorbent by binding to its carbon. The sorbent particles are isolated from the aqueous solution in the presence of an external magnetic field. Then an appropriate organic solvent (acetone) is used to desorb the analytes from the sorbent. Finally, the obtained supernatant is mixed with an extraction solvent and injected into deionized water in order to achieve high enrichment factors and sensitivity. Several significant factors affecting the performance of the introduced method were investigated and optimized. Under the optimum experimental conditions, the extraction recoveries of the proposed method for the selected analytes ranged from 49-75%. The relative standard deviations were ≤7% for intra- (n = 6) and inter-day (n = 4) precisions at a concentration of 10 μg L -1 of each analyte. The limits of detection were in the range of 0.15-0.36 μg L -1 . Finally, the applicability of the proposed method was evaluated by analysis of the selected analytes in some fruit juices. Copyright © 2017 Elsevier B.V. All rights reserved.

Optimisation of solid-phase microextraction combined with gas chromatography-mass spectrometry based methodology to establish the global volatile signature in pulp and skin of Vitis vinifera L. grape varieties.

PubMed

Perestrelo, Rosa; Barros, António S; Rocha, Sílvia M; Câmara, José S

2011-09-15

The volatiles (VOCs) and semi-volatile organic compounds (SVOCs) responsible for aroma are mainly present in skin of grape varieties. Thus, the present investigation is directed towards the optimisation of a solvent free methodology based on headspace-solid-phase microextraction (HS-SPME) combined with gas chromatography-quadrupole mass spectrometry (GC-qMS) in order to establish the global volatile composition in pulp and skin of Bual and Bastardo Vitis vinifera L. varieties. A deep study on the extraction-influencing parameters was performed, and the best results, expressed as GC peak area, number of identified compounds and reproducibility, were obtained using 4 g of sample homogenised in 5 mL of ultra-pure Milli-Q water in a 20 mL glass vial with addition of 2g of sodium chloride (NaCl). A divinylbenzene/carboxen/polydimethylsiloxane fibre was selected for extraction at 60°C for 45 min under continuous stirring at 800 rpm. More than 100 VOCs and SVOCs, including 27 monoterpenoids, 27 sesquiterpenoids, 21 carbonyl compounds, 17 alcohols (from which 2 aromatics), 10 C(13) norisoprenoids and 5 acids were identified. The results showed that, for both grape varieties, the levels and number of volatiles in skin were considerably higher than those observed in pulp. According to the data obtained by principal component analysis (PCA), the establishment of the global volatile signature of grape and the relationship between different part of grapes-pulp and skin, may be an useful tool to winemaker decision to define the vinification procedures that improves the organoleptic characteristics of the corresponding wines and consequently contributed to an economic valorization and consumer acceptance. Copyright © 2011 Elsevier B.V. All rights reserved.

Ultra-preconcentration and determination of selected pharmaceutical and personal care products in different water matrices by solid-phase extraction combined with dispersive liquid-liquid microextraction prior to ultra high pressure liquid chromatography tandem mass spectrometry analysis.

PubMed

Celano, Rita; Piccinelli, Anna Lisa; Campone, Luca; Rastrelli, Luca

2014-08-15

Pharmaceutical and personal care products (PPCPs) are one of the most important classes of emerging contaminants. The potential of ecological and environmental impacts associated with PPCPs are of particular concern because they continually penetrate the aquatic environment. This work describes a novel ultra-preconcentration technique for the rapid and highly sensitive analysis of selected PPCPs in environmental water matrices at ppt levels. Selected PPCPs were rapidly extracted and concentrated from large volumes of aqueous solutions (500 and 250mL) by solid-phase extraction combined with dispersive liquid-liquid microextraction (SPE-DLLME) and then analyzed using UHPLC-MS/MS. Experimental parameters were carefully investigated and optimized to achieve the best SPE-DLLME efficiency and higher enrichment factors. The best results were obtained using the ternary mixture acetonitrile/methanol/dichloromethane 3:3:4, v/v/v, both as SPE eluent and DLLME extractant/dispersive mixture. DLLME aqueous solution (5% NaCl, 10mgL(-1) TBAB) was also modified to improve the extraction efficiency of more hydrophilic PPCPs. Under the optimal conditions, an exhaustive extraction for most of the investigated analytes (recoveries >70%), with a precision (RSD <10%) and very high enrichment factors were attained for different aqueous matrices (drinking, sea, river and wastewater). Method detection and quantification limits were at very low ppt levels and below 1 and 3ngL(-1), respectively, for 15 of selected PPCPs. The proposed analytical procedure offers numerous advantages such as the simplicity of operation, rapidity, a high enrichment factor and sensitivity. So it is suitable for monitoring and studies of occurrence of PPCPs in different environmental compartments. Copyright © 2014 Elsevier B.V. All rights reserved.

Ultrasonic assisted dispersive solid-phase microextraction of Eriochrome Cyanine R from water sample on ultrasonically synthesized lead (II) dioxide nanoparticles loaded on activated carbon: Experimental design methodology.

PubMed

Bahrani, Sonia; Ghaedi, Mehrorang; Mansoorkhani, Mohammad Javad Khoshnood; Asfaram, Arash; Bazrafshan, Ali Akbar; Purkait, Mihir Kumar

2017-01-01

The present research focus on designing an appropriate dispersive solid-phase microextraction (UA-DSPME) for preconcentration and determination of Eriochrome Cyanine R (ECR) in aqueous solutions with aid of sonication using lead (II) dioxide nanoparticles loaded on activated carbon (PbO-NPs-AC). This material was fully identified with XRD and SEM. Influence of pH, amounts of sorbent, type and volume of eluent, and sonication time on response properties were investigated and optimized by central composite design (CCD) combined with surface response methodology using STATISTICA. Among different solvents, dimethyl sulfoxide (DMSO) was selected as an efficient eluent, which its combination by present nanoparticles and application of ultrasound waves led to enhancement in mass transfer. The predicted maximum extraction (100%) under the optimum conditions of the process variables viz. pH 4.5, eluent 200μL, adsorbent dosage 2.5mg and 5min sonication was close to the experimental value (99.50%). at optimum conditions some experimental features like wide 5-2000ngmL -1 ECR, low detection limit (0.43ngmL -1 , S/N=3:1) and good repeatability and reproducibility (relative standard deviation, <5.5%, n=12) indicate versatility in successful applicability of present method for real sample analysis. Investigation of accuracy by spiking known concentration of ECR over 200-600ngmL -1 gave mean recoveries from 94.850% to 101.42% under optimal conditions. The procedure was also applied for the pre-concentration and subsequent determination of ECR in tap and waste waters. Copyright © 2016 Elsevier B.V. All rights reserved.

Solid-phase microextraction coupled to liquid chromatography for the analysis of phenolic compounds in water.

PubMed

González-Toledo, E; Prat, M D; Alpendurada, M F

2001-07-20

Solid-phase microextraction (SPME) coupled to high-performance liquid chromatography (HPLC) has been applied to the analysis of priority pollutant phenolic compounds in water samples. Two types of polar fibers [50 microm Carbowax-templated resin (CW-TPR) and 60 microm polydimethylsiloxane-divinylbenzene (PDMS-DVB)] were evaluated. The effects of equilibration time and ionic strength of samples on the adsorption step were studied. The parameters affecting the desorption process, such as desorption mode, solvent composition and desorption time, were optimized. The developed method was used to determine the phenols in spiked river water samples collected in the Douro River, Portugal. Detection limits of 1-10 microg l(-1) were achieved under the optimized conditions.

Application of solid-phase microextraction method to determine bioavailable fraction of PAH in hazardous waste.

PubMed

Jefimova, J; Irha, N; Mägi, R; Kirso, U

2012-10-01

The solid-phase microextraction (SPME) method was developed to determine PAH free dissolved concentration (C(free)) in field leachates from hazardous waste disposal. SPME technique, involving a 100-μm polydimethylsiloxane (PDMS) fiber coupled to GC-MS was optimized for determination of C(free). The following PAH were found in bioavailable form: acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, with C(free) varying between 2.38 and 62.35 ng/L. Conventional solvent extraction was used for measurement of total concentration (C(total)) in the same samples, and ranging from 1.26 to 77.56 μg/L. Determining C(free) of the hydrophobic toxic pollutants could give useful information for risk assessment of the hazardous waste.

Analysis of Volatile Fragrance and Flavor Compounds by Headspace Solid Phase Microextraction and GC-MS: An Undergraduate Instrumental Analysis Experiment

NASA Astrophysics Data System (ADS)

Galipo, Randolph C.; Canhoto, Alfredo J.; Walla, Michael D.; Morgan, Stephen L.

1999-02-01

A senior-level undergraduate laboratory experiment that demonstrates the use of solid-phase microextraction (SPME) and capillary gas chromatography-mass spectrometry (GC-MS) was developed for the identification of volatile compounds in consumer products. SPME minimizes sample preparation and concentrates volatile analytes in a solvent-free manner. Volatile flavor and fragrance compounds were extracted by SPME from the headspace of vials containing shampoos, chewing gums, and perfumes and analyzed by GC-MS. Headspace SPME was shown to be more sensitive than conventional headspace analysis of similar samples performed with an airtight syringe. Analysis times were less than 30 min, allowing multiple analyses to be performed in a typical laboratory class period.

Extraction and preconcentration of residual solvents in pharmaceuticals using dynamic headspace-liquid phase microextraction and their determination by gas chromatography-flame ionization detection.

PubMed

Farajzadeh, Mir Ali; Dehghani, Hamideh; Yadeghari, Adeleh; Khoshmaram, Leila

2017-02-01

The present study describes a microextraction and determination method for analyzing residual solvents in pharmaceutical products using dynamic headspace-liquid phase microextraction technique followed by gas chromatography-flame ionization detection. In this method dimethyl sulfoxide (μL level) placed into a GC liner-shaped extraction vessel is used as a collection/extraction solvent. Then the liner is exposed to the headspace of a vial containing the sample solution. The effect of different parameters influencing the microextraction procedure including collection/extraction solvent type and its volume, ionic strength, extraction time, extraction temperature and concentration of NaOH solution used in dissolving the studied pharmaceuticals are investigated and optimized. Under the optimum extraction conditions, the method showed wide linear ranges between 0.5 and 5000 mg L -1 . The other analytical parameters were obtained in the following ranges: enrichment factors 240-327, extraction recoveries 72-98% and limits of detection 0.1-0.8 mg L -1 in solution and 0.6-3.2 μg g -1 in solid. Relative standard deviations for the extraction of 100 mg L -1 of each analyte were obtained in the ranges of 4-7 and 5-8% for intra-day (n = 6) and inter-day (n = 4) respectively. Finally the target analytes were determined in different samples such as erythromycin, azithromycin, cefalexin, amoxicillin and co-amoxiclav by the proposed method. Copyright © 2016 John Wiley & Sons, Ltd.

Matrix solid-phase dispersion coupled with homogeneous ionic liquid microextraction for the determination of sulfonamides in animal tissues using high-performance liquid chromatography.

PubMed

Wang, Zhibing; He, Mengyu; Jiang, Chunzhu; Zhang, Fengqing; Du, Shanshan; Feng, Wennan; Zhang, Hanqi

2015-12-01

Matrix solid-phase dispersion coupled with homogeneous ionic liquid microextraction was developed and applied to the extraction of some sulfonamides, including sulfamerazine, sulfamethazine, sulfathiazole, sulfachloropyridazine, sulfadoxine, sulfisoxazole, and sulfaphenazole, in animal tissues. High-performance liquid chromatography was applied to the separation and determination of the target analytes. The solid sample was directly treated by matrix solid-phase dispersion and the eluate obtained was treated by homogeneous ionic liquid microextraction. The ionic liquid was used as the extraction solvent in this method, which may result in the improvement of the recoveries of the target analytes. To avoid using organic solvent and reduce environmental pollution, water was used as the elution solvent of matrix solid-phase dispersion. The effects of the experimental parameters on recoveries, including the type and volume of ionic liquid, type of dispersant, ratio of sample to dispersant, pH value of elution solvent, volume of elution solvent, amount of salt in eluate, amount of ion-pairing agent (NH4 PF6 ), and centrifuging time, were evaluated. When the present method was applied to the analysis of animal tissues, the recoveries of the analytes ranged from 85.4 to 118.0%, and the relative standard deviations were lower than 9.30%. The detection limits for the analytes were 4.3-13.4 μg/kg. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Three-phase molecularly imprinted sol-gel based hollow fiber liquid-phase microextraction combined with liquid chromatography-tandem mass spectrometry for enrichment and selective determination of a tentative lung cancer biomarker.

PubMed

Moein, Mohammad Mahdi; Javanbakht, Mehran; Karimi, Mohammad; Akbari-Adergani, Behrouz; Abdel-Rehim, Mohamed

2015-07-15

In the present study, the modification of a polysulfone hollow fiber membrane with in situ molecularly imprinted sol-gel process (as a novel and one-step method) was prepared and investigated. 3-(propylmethacrylate)trimethoxysilane (3PMTMOS) as an inorganic precursor was used for preparation of molecularly imprinted sol-gel. The modified molecularly imprinted sol-gel hollow fiber membrane (MSHM) was used for the liquid-phase microextraction (LPME) of hippuric acid (HA) in human plasma and urine samples. MSHM as a selective, robust, and durable tool was used for at least 50 extractions without significant decrease in the extraction efficiency. The non-molecularly imprinted sol-gel hollow fiber membrane (NSHM) as blank hollow fiber membrane was prepared by the same process, only without HA. To achieve the best condition, influential parameters on the extraction efficiency were thoroughly investigated. The capability of this robust, green, and simple method for extraction of HA was successfully accomplished with LC/MS/MS. The limits of detection (LOD) and quantification (LOQ) in human plasma and urine samples were 0.3 and 1.0nmolL(-1), respectively. The standard calibration curves were obtained within the concentration range 1-2000nmolL(-1) for HA in human plasma and urine. The coefficients of determination (r(2)) were ≥0.998. The obtained data exhibited recoveries were higher than 89% for the extraction of HA in human plasma and urine samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Validation of an Analytical Method for Determination of 13 priority polycyclic aromatic hydrocarbons in mineral water using dispersive liquid-liquid microextraction and GC-MS

PubMed Central

Sadeghi, Ramezan; Kobarfard, Farzad; Yazdanpanah, Hassan; Eslamizad, Samira; Bayat, Mitra

2016-01-01

Dispersive liquid-liquid microextraction (DLLME) combined with gas chromatography–mass spectrometry (GC–MS) was used for the extraction and determination of 13 polycyclic aromatic hydrocarbons (PAHs) in mineral water samples. In this procedure, the suitable combination of extraction solvent (500 µL chloroform) and disperser solvent (1000 µL acetone) were quickly injected into the water sample (10.00 mL) by Hamilton syringe. After centrifugation, 500 µL of the lower organic phase was dried under a gentle stream of nitrogen, re-dissolved in chloroform and injected into GC-MS. Chloroform and acetone were found to be the best extraction and disperser solvent, respectively. Validation of the method was performed using spiked calibration curves. The enrichment factor ranged from 93 to 129 and the recovery ranged from 71 to 90%. The linear ranges for all the PAHs were 0.10-2.80 ngmL-1. The relative standard deviations (RSDs) of PAHs in water by using anthracene-d10 as internal standard, were in the range of 4-11% for most of the analytes (n = 3). Limit of detection (LOD) for different PAHs were between 0.03 and 0.1 ngmL-1. The method was successfully applied for the analysis of PAHs in mineral water samples collected from Tehran. PMID:27610156

A novel hybrid metal-organic framework-polymeric monolith for solid-phase microextraction.

PubMed

Lin, Chen-Lan; Lirio, Stephen; Chen, Ya-Ting; Lin, Chia-Her; Huang, Hsi-Ya

2014-03-17

This study describes the fabrication of a novel hybrid metal-organic framework- organic polymer (MOF-polymer) for use as a stationary phase in fritless solid-phase microextraction (SPME) for validating analytical methods. The MOF-polymer was prepared by using ethylene dimethacrylate (EDMA), butyl methacrylate (BMA), and an imidazolium-based ionic liquid as porogenic solvent followed by microwave-assisted polymerization with the addition of 25 % MOF. This novel hybrid MOF-polymer was used to extract penicillin (penicillin G, penicillin V, oxacillin, cloxacillin, nafcillin, dicloxacillin) under different conditions. Quantitative analysis of the extracted penicillin samples using the MOF-organic polymer for SPME was conducted by using capillary electrochromatography (CEC) coupled with UV analysis. The penicillin recovery was 63-96.2 % with high reproducibility, sensitivity, and reusability. The extraction time with the proposed fabricated SPME was only 34 min. © 2014 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.

Combination of dispersive liquid-liquid microextraction with flame atomic absorption spectrometry using microsample introduction for determination of lead in water samples.

PubMed

Naseri, Mohammad Taghi; Hemmatkhah, Payam; Hosseini, Mohammad Reza Milani; Assadi, Yaghoub

2008-03-03

The dispersive liquid-liquid microextraction (DLLME) was combined with the flame atomic absorption spectrometry (FAAS) for determination of lead in the water samples. Diethyldithiophosphoric acid (DDTP), carbon tetrachloride and methanol were used as chelating agent, extraction solvent and disperser solvent, respectively. A new FAAS sample introduction system was employed for the microvolume nebulization of the non-flammable chlorinated organic extracts. Injection of 20 microL volumes of the organic extract into an air-acetylene flame provided very sensitive spike-like and reproducible signals. Some effective parameters on the microextraction and the complex formation were selected and optimized. These parameters include extraction and disperser solvent type as well as their volume, extraction time, salt effect, pH and amount of the chelating agent. Under the optimized conditions, the enrichment factor of 450 was obtained from a sample volume of 25.0 mL. The enhancement factor, calculated as the ratio of the slopes of the calibration graphs with and without preconcentration, which was about 1000. The calibration graph was linear in the range of 1-70 microgL(-1) with a detection limit of 0.5 microgL(-1). The relative standard deviation (R.S.D.) for seven replicate measurements of 5.0 and 50 microgL(-1) of lead were 3.8 and 2.0%, respectively. The relative recoveries of lead in tap, well, river and seawater samples at the spiking level of 20 microgL(-1) ranged from 93.8 to 106.2%. The characteristics of the proposed method were compared with those of the liquid-liquid extraction (LLE), cloud point extraction (CPE), on-line and off-line solid-phase extraction (SPE) as well as co-precipitation, based on bibliographic data. Operation simplicity, rapidity, low cost, high enrichment factor, good repeatability, and low consumption of the extraction solvent at a microliter level are the main advantages of the proposed method.

Multivariate analysis of the volatile components in tobacco based on infrared-assisted extraction coupled to headspace solid-phase microextraction and gas chromatography-mass spectrometry.

PubMed

Yang, Yanqin; Pan, Yuanjiang; Zhou, Guojun; Chu, Guohai; Jiang, Jian; Yuan, Kailong; Xia, Qian; Cheng, Changhe

2016-11-01

A novel infrared-assisted extraction coupled to headspace solid-phase microextraction followed by gas chromatography with mass spectrometry method has been developed for the rapid determination of the volatile components in tobacco. The optimal extraction conditions for maximizing the extraction efficiency were as follows: 65 μm polydimethylsiloxane-divinylbenzene fiber, extraction time of 20 min, infrared power of 175 W, and distance between the infrared lamp and the headspace vial of 2 cm. Under the optimum conditions, 50 components were found to exist in all ten tobacco samples from different geographical origins. Compared with conventional water-bath heating and nonheating extraction methods, the extraction efficiency of infrared-assisted extraction was greatly improved. Furthermore, multivariate analysis including principal component analysis, hierarchical cluster analysis, and similarity analysis were performed to evaluate the chemical information of these samples and divided them into three classifications, including rich, moderate, and fresh flavors. The above-mentioned classification results were consistent with the sensory evaluation, which was pivotal and meaningful for tobacco discrimination. As a simple, fast, cost-effective, and highly efficient method, the infrared-assisted extraction coupled to headspace solid-phase microextraction technique is powerful and promising for distinguishing the geographical origins of the tobacco samples coupled to suitable chemometrics. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Analysis of volatile organic compounds in pleural effusions by headspace solid-phase microextraction coupled with cryotrap gas chromatography and mass spectrometry.

PubMed

Huang, Zhongping; Zhang, Jie; Zhang, Peipei; Wang, Hong; Pan, Zaifa; Wang, Lili

2016-07-01

Headspace solid-phase microextraction coupled with cryotrap gas chromatography and mass spectrometry was applied to the analysis of volatile organic compounds in pleural effusions. The highly volatile organic compounds were separated successfully with high sensitivity by the employment of a cryotrap device, with the construction of a cold column head by freezing a segment of metal capillary with liquid nitrogen. A total of 76 volatile organic compounds were identified in 50 pleural effusion samples (20 malignant effusions and 30 benign effusions). Among them, 34 more volatile organic compounds were detected with the retention time less than 8 min, by comparing with the normal headspace solid-phase microextraction coupled with gas chromatography and mass spectrometry method. Furthermore, 24 volatile organic compounds with high occurrence frequency in pleural effusion samples, 18 of which with the retention time less than 8 min, were selected for the comparative analysis. The results of average peak area comparison and box-plot analysis showed that except for cyclohexanone, 2-ethyl-1-hexanol, and tetramethylbenzene, which have been reported as potential cancer biomarkers, cyclohexanol, dichloromethane, ethyl acetate, n-heptane, ethylbenzene, and xylene also had differential expression between malignant and benign effusions. Therefore, the proposed approach was valuable for the comprehensive characterization of volatile organic compounds in pleural effusions. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Application of solid-phase microextraction with gas chromatography and mass spectrometry for the early detection of active moulds on historical woollen objects.

PubMed

Sawoszczuk, Tomasz; Syguła-Cholewińska, Justyna; Del Hoyo-Meléndez, Julio M

2017-02-01

The goal of this work was to determine the microbial volatile organic compounds emitted by moulds growing on wool in search of particular volatiles mentioned in the literature as indicators of active mould growth. The keratinolytically active fungi were inoculated on two types of media: (1) samples of wool placed on broths, and (2) on broths containing amino acids that are elements of the structure of keratin. All samples were prepared inside 20 mL vials (closed system). In the first case (1) the broths did not contain any sources of organic carbon, nitrogen, or sulfur, i.e. wool was the only nutrient for the moulds. A third type of sample was historical wool prepared in a Petri dish without a broth and inoculated with a keratinolytically active mould (open system). The microbial volatiles emitted by moulds were sampled with the headspace solid-phase microextraction method. Volatiles extracted on solid-phase microextraction fibers were analyzed in a gas chromatography with mass spectrometry system. Qualitative and quantitative analyses of chromatograms were carried out in search of indicators of metabolic activity. The results showed that there are three groups of volatiles that can be used for the detection of active forms of moulds on woollen objects. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of solid-phase microextraction coupled with liquid chromatography for analysis of tramadol in brain tissue using its molecularly imprinted polymer.

PubMed

Habibi-Khorasani, Monireh; Mohammadpour, Amir Hooshang; Mohajeri, Seyed Ahmad

2017-02-01

In this work, performance of a molecularly imprinted polymer (MIP) as a selective solid-phase microextraction sorbent for the extraction and enrichment of tramadol in aqueous solution and rabbit brain tissue, is described. Binding properties of MIPs were studied in comparison with their nonimprinted polymer (NIP). Ten milligrams of the optimized MIP was then evaluated as a sorbent, for preconcentration, in molecularly imprinted solid-phase microextraction (MISPME) of tramadol from aqueous solution and rabbit brain tissue. The analytical method was calibrated in the range of 0.004 ppm (4 ng mL -1 ) and 10 ppm (10 μg mL -1 ) in aqueous media and in the ranges of 0.01 and 10 ppm in rabbit brain tissue, respectively. The results indicated significantly higher binding affinity of MIPs to tramadol, in comparison with NIP. The MISPME procedure was developed and optimized with a recovery of 81.12-107.54% in aqueous solution and 76.16-91.20% in rabbit brain tissue. The inter- and intra-day variation values were <8.24 and 5.06%, respectively. Finally the calibrated method was applied for determination of tramadol in real rabbit brain tissue samples after administration of a lethal dose. Our data demonstrated the potential of MISPME for rapid, sensitive and cost-effective sample analysis. Copyright © 2016 John Wiley & Sons, Ltd.

PEEK tube-based online solid-phase microextraction-high-performance liquid chromatography for the determination of yohimbine in rat plasma and its application in pharmacokinetics study.

PubMed

Xiang, Xiaowei; Shang, Bing; Wang, Xiaozheng; Chen, Qinhua

2017-04-01

Yohimbine is a novel compound for the treatment of erectile dysfunction derived from natural products, and pharmacokinetic study is important for its further development as a new medicine. In this work, we developed a novel PEEK tube-based solid-phase microextraction (SPME)-HPLC method for analysis of yohimbine in plasma and further for pharmacokinetic study. Poly (AA-EGDMA) was synthesized inside a PEEK tube as the sorbent for microextraction of yohimbine, and parameters that could influence extraction efficiency were systematically investigated. Under optimum conditions, the PEEK tube-based SPME method exhibits excellent enrichment efficiency towards yohimbine. By using berberine as internal standard, an online SPME-HPLC method was developed for analysis of yohimbine in human plasma sample. The method has wide linear range (2-1000 ng/mL) with an R 2 of 0.9962; the limit of detection was determined and was as low as 0.1 ng/mL using UV detection. Finally, a pharmacokinetic study of yohimbine was carried out by the online SPME-HPLC method and the results have been compared with those of reported methods. Copyright © 2016 John Wiley & Sons, Ltd.

Simultaneous determination of cyanogen chloride and cyanogen bromide in treated water at sub-microg/L levels by a new solid-phase microextraction-gas chromatographic-electron-capture detection method.

PubMed

Cancho, B; Ventur, F; Galceran, M

2000-11-03

A headspace solid-phase microextraction (HS-SPME) procedure has been developed and applied for the determination of cyanogen halides in treated water samples at microg/L concentrations. Several SPME coatings were tested, the divinylbenzene-Carboxen-polydimethylsiloxane fiber being the most appropriate coating. GC-electron-capture detection was used for separation and quantitation. Experimental parameters such as sample volume, addition of a salt, extraction time and desorption conditions were studied. The optimized method has an acceptable linearity, good precision, with RSD values <10% for both compounds, and it is sufficiently sensitive to detect ng/L levels. HS-SPME was compared with liquid-liquid microextraction (US Environmental Protection Agency Method 551.1) for the analysis of spiked ultrapure and granular activated carbon filtered water samples. There was good agreement between the results from both methods. Finally, the optimized procedure was applied to determine both compounds at the Barcelona water treatment plant (N.E. Spain). Cyanogen chloride in treated water was <1.0 microg/L and cyanogen bromide ranged from 3.2 to 6.4 microg/L.

Role of microextraction sampling procedures in forensic toxicology.

PubMed

Barroso, Mário; Moreno, Ivo; da Fonseca, Beatriz; Queiroz, João António; Gallardo, Eugenia

2012-07-01

The last two decades have provided analysts with more sensitive technology, enabling scientists from all analytical fields to see what they were not able to see just a few years ago. This increased sensitivity has allowed drug detection at very low concentrations and testing in unconventional samples (e.g., hair, oral fluid and sweat), where despite having low analyte concentrations has also led to a reduction in sample size. Along with this reduction, and as a result of the use of excessive amounts of potentially toxic organic solvents (with the subsequent environmental pollution and costs associated with their proper disposal), there has been a growing tendency to use miniaturized sampling techniques. Those sampling procedures allow reducing organic solvent consumption to a minimum and at the same time provide a rapid, simple and cost-effective approach. In addition, it is possible to get at least some degree of automation when using these techniques, which will enhance sample throughput. Those miniaturized sample preparation techniques may be roughly categorized in solid-phase and liquid-phase microextraction, depending on the nature of the analyte. This paper reviews recently published literature on the use of microextraction sampling procedures, with a special focus on the field of forensic toxicology.

Rapid analysis of aflatoxins B1, B2, and ochratoxin A in rice samples using dispersive liquid-liquid microextraction combined with HPLC.

PubMed

Lai, Xian-Wen; Sun, Dai-Li; Ruan, Chun-Qiang; Zhang, He; Liu, Cheng-Lan

2014-01-01

A novel, simple, and rapid method is presented for the analysis of aflatoxin B1, aflatoxin B2, and ochratoxin A in rice samples by dispersive liquid-liquid microextraction combined with LC and fluorescence detection. After extraction of the rice samples with a mixture of acetonitrile/water/acetic acid, mycotoxins were rapidly partitioned into a small volume of organic solvent (chloroform) by dispersive liquid-liquid microextraction. The three mycotoxins were simultaneously determined by LC with fluorescence detection after precolumn derivatization for aflatoxin B1 and B2. Parameters affecting both extraction and dispersive liquid-liquid microextraction procedures, including the extraction solvent, the type and volume of extractant, the volume of dispersive solvent, the addition of salt, the pH and the extraction time, were optimized. The optimized protocol provided an enrichment factor of approximately 1.25 and with detection of limits (0.06-0.5 μg/kg) below the maximum levels imposed by current regulations for aflatoxins and ochratoxin A. The mean recovery of three mycotoxins ranged from 82.9-112%, with a RSD less than 7.9% in all cases. The method was successfully applied to measure mycotoxins in commercial rice samples collected from local supermarkets in China. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solid-phase extraction combined with dispersive liquid-liquid microextraction and chiral liquid chromatography-tandem mass spectrometry for the simultaneous enantioselective determination of representative proton-pump inhibitors in water samples.

PubMed

Zhao, Pengfei; Deng, Miaoduo; Huang, Peiting; Yu, Jia; Guo, Xingjie; Zhao, Longshan

2016-09-01

This report describes, for the first time, the simultaneous enantioselective determination of proton-pump inhibitors (PPIs-omeprazole, lansoprazole, pantoprazole, and rabeprazole) in environmental water matrices based on solid-phase extraction combined with dispersive liquid-liquid microextraction (SPE-DLLME) and chiral liquid chromatography-tandem mass spectrometry. The optimized results of SPE-DLLME were obtained with PEP-2 column using methanol-acetonitrile (1/1, v/v) as elution solvent, dichloroethane, and acetonitrile as extractant and disperser solvent, respectively. The separation and determination were performed using reversed-phase chromatography on a cellulose chiral stationary phase, a Chiralpak IC (250 mm × 4.6 mm, 5 μm) column, under isocratic conditions at 0.6 mL min(-1) flow rate. The analytes were detected in multiple reaction monitoring (MRM) mode by triple quadrupole mass spectrometry. Isotopically labeled internal standards were used to compensate matrix interferences. The method provided enrichment factors of around 500. Under optimal conditions, the mean recoveries for all eight enantiomers from the water samples were 89.3-107.3 % with 0.9-10.3 % intra-day RSD and 2.3-8.1 % inter-day RSD at 20 and 100 ng L(-1) levels. Correlation coefficients (r (2)) ≥ 0.999 were achieved for all enantiomers within the range of 2-500 μg L(-1). The method detection and quantification limits were at very low levels, within the range of 0.67-2.29 ng L(-1) and 2.54-8.68 ng L(-1), respectively. This method was successfully applied to the determination of the concentrations and enantiomeric fractions of the targeted analytes in wastewater and river water, making it applicable to the assessment of the enantiomeric fate of PPIs in the environment. Graphical Abstract Simultaneous enantioselective determination of representative proton-pump inhibitors in water samples.

Determination of hydroxyaromatic compounds in water by solid-phase microextraction coupled to high-performance liquid chromatography.

PubMed

Wu, Y C; Huang, S D

1999-03-12

Solid-phase microextraction (SPME) coupled with high-performance liquid chromatography (HPLC) for the analysis of hydroxyaromatic compounds is described. Three kinds of fibers [50 microns carbowax-templated resin (CW-TPR), 60 microns polydimethylsiloxane-divinylbenzene (PDMS-DVB) and 85 microns polyacrylate (PA) fibers] were evaluated. CW-TPR and PDMS-DVB were selected for further study. The parameters of the desorption procedure (such as desorption mode, the composition of the solvent for desorption and the duration of fiber soaking) were studied and optimized. The effect of the structure and physical properties of analytes, carryover, duration of absorption, temperature of absorption, pH and ionic strength of samples were also investigated. The method was applied to environmental samples (lake water) using a simple calibration curve.

The leaf volatile constituents of Isatis tinctoria by Solid-Phase Microextraction and Gas chromatography/Mass Spectrometry.

PubMed

Condurso, Cettina; Verzera, Antonella; Romeo, Vincenza; Ziino, Marisa; Trozzi, Alessandra; Ragusa, Salvatore

2006-08-01

The leaf volatile constituents of Isatis tinctoria L. (Brassicaceae) have been studied by Solid-Phase Microextraction and Gas chromatography/Mass Spectrometry (SPME/GC-MS). Seventy components were fully characterized by mass spectra, linear retention indices, and injection of standards; the average composition (ppm) as single components and classes of substances is reported. Aliphatic hydrocarbons, acids, alcohols, aldehydes and esters, aromatic aldehydes, esters and ethers, furans, isothiocyanates and thiocyanates, sulfurated compounds, nitriles, terpenes and sesquiterpenes were identified. Leaf volatiles in Isatis tinctoria L. were characterized by a high amount of isothiocyanates which accounted for about 40 % of the total volatile fraction. Isothiocyanates are important and characteristic flavour compounds in Brassica vegetables and the cancer chemo-protective attributes are recently responsible for their growing interest.

Comparison of different coatings in solid-phase microextraction for the determination of organochlorine pesticides in ground water.

PubMed

Pérez-Trujillo, J P; Frías, S; Conde, J E; Rodríguez-Delgado, M A

2002-07-19

A solid-phase microextraction (SPME) procedure using three commercialised fibers (Carbowax-divinylbenzene, Carboxen-polydimethylsiloxane and divinylbenzene-Carboxen-polydimethylsiloxane) is presented for the determination of a selected group of organochlorine compounds in water samples. The extraction performances of these compounds were compared using fibers with two and three coatings. The optimal experimental procedures for the adsorption and desorption of pesticides were determined. The limits of detection with the divinylbenzene-Carboxen-polydimethylsiloxane fiber at levels below ng l(-1) were similar or lower than values presented in the literature for several of these compounds using polydimethylsiloxane fiber. The advantages of using this fiber, such as no salt addition, are discussed. Finally, the optimised procedures were applied successfully for the determination of these compounds in polluted ground water samples.

Developing a New Sampling And Analysis Method For Hydrazine And Monomethyl Hydrazine: Using a Derivatizing Agent With Solid Phase Microextraction

NASA Technical Reports Server (NTRS)

Allen, John

2001-01-01

Solid phase microextraction (SPME) will be used to develop a method for detecting monomethyl hydrazine (MMH) and hydrazine (Hz). A derivatizing agent, pentafluorobenzoyl chloride (PFBCI), is known to react readily with MMH and Hz. The SPME fiber can either be coated with PFBCl and introduced into a gaseous stream containing MMH, or PFBCl and MMH can react first in a syringe barrel and after a short equilibration period a SPME is used to sample the resulting solution. These methods were optimized and compared. Because Hz and MMH can degrade the SPME, letting the reaction occur first gave better results. Only MMH could be detected using either of these methods. Future research will concentrate on constructing calibration curves and determining the detection limit.

Analysis of Volatile Components of Cape Gooseberry (Physalis peruviana L.) Grown in Turkey by HS-SPME and GC-MS

PubMed Central

2014-01-01

Volatile components in cape gooseberry fruit at ripe stage were collected using headspace-solid phase microextraction, and analyzed by gas chromatography-mass spectrometry. Three solid phase microextraction fiber coatings (DVB/CAR/PDMS, CAR/PDMS, and PDMS/DVB) were tested for evaluation of volatile compounds. DVB/CAR/PDMS fiber showed a strong extraction capacity for volatile compounds and produced the best result in case of total peak areas. A total of 133 volatile compounds were identified in fruit pulp; among them 1-hexanol (6.86%), eucalyptol (6.66%), ethyl butanoate (6.47%), ethyl octanoate (4.01%), ethyl decanoate (3.39%), 4-terpineol (3.27%), and 2-methyl-1-butanol (3.10%) were the major components in the sample extracts. PMID:24741358

Analysis of volatile components of cape gooseberry (Physalis peruviana L.) grown in Turkey by HS-SPME and GC-MS.

PubMed

Yilmaztekin, Murat

2014-01-01

Volatile components in cape gooseberry fruit at ripe stage were collected using headspace-solid phase microextraction, and analyzed by gas chromatography-mass spectrometry. Three solid phase microextraction fiber coatings (DVB/CAR/PDMS, CAR/PDMS, and PDMS/DVB) were tested for evaluation of volatile compounds. DVB/CAR/PDMS fiber showed a strong extraction capacity for volatile compounds and produced the best result in case of total peak areas. A total of 133 volatile compounds were identified in fruit pulp; among them 1-hexanol (6.86%), eucalyptol (6.66%), ethyl butanoate (6.47%), ethyl octanoate (4.01%), ethyl decanoate (3.39%), 4-terpineol (3.27%), and 2-methyl-1-butanol (3.10%) were the major components in the sample extracts.

ZnO nanorod array polydimethylsiloxane composite solid phase micro-extraction fiber coating: fabrication and extraction capability.

PubMed

Wang, Dan; Wang, Qingtang; Zhang, Zhuomin; Chen, Guonan

2012-01-21

ZnO nanorod array coating is a novel kind of solid-phase microextraction (SPME) fiber coating which shows good extraction capability due to the nanostructure. To prepare the composite coating is a good way to improve the extraction capability. In this paper, the ZnO nanorod array polydimethylsiloxane (PDMS) composite SPME fiber coating has been prepared and its extraction capability for volatile organic compounds (VOCs) has been studied by headspace sampling the typical volatile mixed standard solution of benzene, toluene, ethylbenzene and xylene (BTEX). Improved detection limit and good linear ranges have been achieved for this composite SPME fiber coating. Also, it is found that the composite SPME fiber coating shows good extraction selectivity to the VOCs with alkane radicals.

Offline solid phase microextraction sampling system

DOEpatents

Harvey, Chris A.

2008-12-16

An offline solid phase microextraction (SPME) sampling apparatus for enabling SPME samples to be taken a number of times from a previously collected fluid sample (e.g. sample atmosphere) stored in a fused silica lined bottle which keeps volatile organics in the fluid sample stable for weeks at a time. The offline SPME sampling apparatus has a hollow body surrounding a sampling chamber, with multiple ports through which a portion of a previously collected fluid sample may be (a) released into the sampling chamber, (b) SPME sampled to collect analytes for subsequent GC analysis, and (c) flushed/purged using a fluidically connected vacuum source and purging fluid source to prepare the sampling chamber for additional SPME samplings of the same original fluid sample, such as may have been collected in situ from a headspace.

Magnetical hollow fiber bar collection of extract in homogenous ionic liquid microextraction of triazine herbicides in water samples.

PubMed

Wang, Kun; Jiang, Jia; Kang, Mingqin; Li, Dan; Zang, Shuang; Tian, Sizhu; Zhang, Hanqi; Yu, Aimin; Zhang, Ziwei

2017-04-01

The homogeneous ionic liquid microextraction combined with magnetical hollow fiber bar collection was developed for extracting triazine herbicides from water samples. These analytes were separated and determined by high performance liquid chromatography. The triazines were quickly extracted into ionic liquid microdroplets dispersed in solution, and then these microdroplets were completely collected with magnetical hollow fiber bars; the pores of which were impregnated with hydrophobic ionic liquid, which makes the phase separation simplified with no need of centrifugation. Some experimental parameters, such as the type of ionic liquid, ultrasonic immersion time of hollow fiber, pH of sample solution, volume of hydrophilic ionic liquid, amount of ion-pairing agent NH 4 PF 6 , NaCl concentration, number of magnetical hollow fiber bar, stirring rate, and collection time were investigated and optimized. When the present method was applied to the analysis of real water samples, the precision and recoveries of six triazine herbicides vary from 0.1 to 9.2% and 73.4 to 118.5%, respectively. The detection limits for terbumeton, ametryn, prometryn, terbutryn, trietazine, and dimethametryn were 0.48, 0.15, 0.15, 0.14, 0.35, and 0.16 μg L -1 , respectively.

Indirect spectrophotometric determination of ultra trace amounts of selenium based on dispersive liquid-liquid microextraction-solidified floating organic drop.

PubMed

Haji Shabani, Ali Mohammad; Dadfarnia, Shayessteh; Nozohor, Mahnaz

2013-12-01

A novel dispersive liquid-liquid microextraction-solidified floating organic drop (DLLME-SFOD) method combined with fiber optic-linear array detection spectrophotometry has been developed for the indirect determination of selenium. The method is based on the oxidation of the I(-) to iodine by inorganic Se(IV). The produced I2 reacts with the excess of I(-) ions in acidic media to give triiodide ions. The I3(-) is then extracted into 1-undecanol by DLLME-SFOD upon the formation of an ion pair with cetyltrimethylammonium cation. The extracted ion pair is determined by measuring its absorption at 360 nm. The absorbance signal is proportional to the selenium concentration in the aqueous phase. Under optimum conditions, the method provided an enrichment factor of 250 with a detection limit of 16.0 μg L(-1) and a linear dynamic range of 40.0-1000.0 μg L(-1). The relative standard deviation was found to be 2.1% (n=7) at 100.0 μg L(-1) concentration level. The method was successfully applied to th e determination of selenium in water samples and selenium plus tablet. Copyright © 2013 Elsevier B.V. All rights reserved.

Highly porous nanostructured copper foam fiber impregnated with an organic solvent for headspace liquid-phase microextraction.

PubMed

Saraji, Mohammad; Ghani, Milad; Rezaei, Behzad; Mokhtarianpour, Maryam

2016-10-21

A new headspace liquid-phase microextraction technique based on using a copper foam nanostructure substrate followed by gas chromatography-flame ionization detection was developed for the determination of volatile organic compounds in water and wastewater samples. The copper foam with highly porous nanostructured walls was fabricated on the surface of a copper wire by a rapid and facile electrochemical process and used as the extractant solvent holder. Propyl benzoate was immobilized in the pores of the copper foam coating and used for the microextraction of benzene, toluene, ethylbenzene and xylenes. The experimental parameters such as the type of organic solvent, desorption temperature, desorption time, salt concentration, sample temperature, equilibrium time and extraction time, were investigated and optimized. Under the optimum conditions, the method detection limit was between 0.06 and 0.25μgL -1 . The relative standard deviation of the method for the analytes at 4-8μgL -1 concentration level ranged from 7.9 to 11%. The fiber-to-fiber reproducibility for three fibers prepared under the same condition was 9.3-12%. The enrichment factor was in the range of 615-744. Different water samples were analyzed for the evaluation of the method in real sample analysis. Relative recoveries for spiked tap, river and wastewater samples were in the range of 85-94%. Finally, the extraction efficiency of the method was compared with those of headspace single drop microextraction and headspace SPME with the commercial fibers. Copyright © 2016 Elsevier B.V. All rights reserved.

A novel dispersive liquid-liquid microextraction based on solidification of floating organic droplet method for determination of polycyclic aromatic hydrocarbons in aqueous samples.

PubMed

Xu, Hui; Ding, Zongqing; Lv, Lili; Song, Dandan; Feng, Yu-Qi

2009-03-16

A new dispersive liquid-liquid microextraction based on solidification of floating organic droplet method (DLLME-SFO) was developed for the determination of five kinds of polycyclic aromatic hydrocarbons (PAHs) in environmental water samples. In this method, no specific holder, such as the needle tip of microsyringe and the hollow fiber, is required for supporting the organic microdrop due to the using of organic solvent with low density and proper melting point. Furthermore, the extractant droplet can be collected easily by solidifying it in the lower temperature. 1-Dodecanol was chosen as extraction solvent in this work. A series of parameters that influence extraction were investigated systematically. Under optimal conditions, enrichment factors (EFs) for PAHs were in the range of 88-118. The limit of detections (LODs) for naphthalene, diphenyl, acenaphthene, anthracene and fluoranthene were 0.045, 0.86, 0.071, 1.1 and 0.66ngmL(-1), respectively. Good reproducibility and recovery of the method were also obtained. Compared with the traditional liquid-phase microextraction (LPME) and dispersive liquid-liquid microextraction (DLLME) methods, the proposed method obtained about 2 times higher enrichment factor than those in LPME. Moreover, the solidification of floating organic solvent facilitated the phase transfer. And most importantly, it avoided using high-density and toxic solvent in the traditional DLLME method. The proposed method was successfully applied to determinate PAHs in the environmental water samples. The simple and low-cost method provides an alternative method for the analysis of non-polar compounds in complex environmental water.

Bubbles in solvent microextraction: the influence of intentionally introduced bubbles on extraction efficiency.

PubMed

Williams, D Bradley G; George, Mosotho J; Meyer, Riaan; Marjanovic, Ljiljana

2011-09-01

Significant improvements to microdrop extractions of triazine pesticides are realized by the intentional incorporation of an air bubble into the solvent microdroplet used in this microextraction technique. The increase is attributed partly to greater droplet surface area resulting from the air bubble being incorporated into the solvent droplet as opposed to it sitting thereon and partly to thin film phenomena. The method is useful at nanogram/liter levels (LOD 0.002-0.012 μg/L, LOQ 0.007-0.039 μg/L), is precise (7-12% at 10 μg/L concentration level), and is validated against certified reference materials containing 0.5 and 5.0 μg/L analyte. It tolerates water and fruit juice as matrixes without serious matrix effects. This new development brings a simple, inexpensive, and efficient preconcentration technique to bear which rivals solid phase microextraction methods.

Zero valent Fe-reduced graphene oxide quantum dots as a novel magnetic dispersive solid phase microextraction sorbent for extraction of organophosphorus pesticides in real water and fruit juice samples prior to analysis by gas chromatography-mass spectrometry.

PubMed

Akbarzade, Samaneh; Chamsaz, Mahmoud; Rounaghi, Gholam Hossein; Ghorbani, Mahdi

2018-01-01

A selective and sensitive magnetic dispersive solid-phase microextraction (MDSPME) coupled with gas chromatography-mass spectrometry was developed for extraction and determination of organophosphorus pesticides (Sevin, Fenitrothion, Malathion, Parathion, and Diazinon) in fruit juice and real water samples. Zero valent Fe-reduced graphene oxide quantum dots (rGOQDs@ Fe) as a new and effective sorbent were prepared and applied for extraction of organophosphorus pesticides using MDSPME method. In order to study the performance of this new sorbent, the ability of rGOQDs@ Fe was compared with graphene oxide and magnetic graphene oxide nanocomposite by recovery experiments of the organophosphorus pesticides. Several affecting parameters in the microextraction procedure, including pH of donor phase, donor phase volume, stirring rate, extraction time, and desorption conditions such as the type and volume of solvents and desorption time were thoroughly investigated and optimized. Under the optimal conditions, the method showed a wide linear dynamic range with R-square between 0.9959 and 0.9991. The limit of detections, the intraday and interday relative standard deviations (n = 5) were less than 0.07 ngmL -1 , 4.7, and 8.6%, respectively. The method was successfully applied for extraction and determination of organophosphorus pesticides in real water samples (well, river and tap water) and fruit juice samples (apple and grape juice). The obtained relative recoveries were in the range of 82.9%-113.2% with RSD percentages of less than 5.8% for all the real samples.

Multivariate analysis of volatile compounds detected by headspace solid-phase microextraction/gas chromatography: A tool for sensory classification of cork stoppers.

PubMed

Prat, Chantal; Besalú, Emili; Bañeras, Lluís; Anticó, Enriqueta

2011-06-15

The volatile fraction of aqueous cork macerates of tainted and non-tainted agglomerate cork stoppers was analysed by headspace solid-phase microextraction (HS-SPME)/gas chromatography. Twenty compounds containing terpenoids, aliphatic alcohols, lignin-related compounds and others were selected and analysed in individual corks. Cork stoppers were previously classified in six different classes according to sensory descriptions including, 2,4,6-trichloroanisole taint and other frequent, non-characteristic odours found in cork. A multivariate analysis of the chromatographic data of 20 selected chemical compounds using linear discriminant analysis models helped in the differentiation of the a priori made groups. The discriminant model selected five compounds as the best combination. Selected compounds appear in the model in the following order; 2,4,6 TCA, fenchyl alcohol, 1-octen-3-ol, benzyl alcohol and benzothiazole. Unfortunately, not all six a priori differentiated sensory classes were clearly discriminated in the model, probably indicating that no measurable differences exist in the chromatographic data for some categories. The predictive analyses of a refined model in which two sensory classes were fused together resulted in a good classification. Prediction rates of control (non-tainted), TCA, musty-earthy-vegetative, vegetative and chemical descriptions were 100%, 100%, 85%, 67.3% and 100%, respectively, when the modified model was used. The multivariate analysis of chromatographic data will help in the classification of stoppers and provide a perfect complement to sensory analyses. Copyright © 2010 Elsevier Ltd. All rights reserved.

Analysis of Odorants in Marking Fluid of Siberian Tiger (Panthera tigris altaica) Using Simultaneous Sensory and Chemical Analysis with Headspace Solid-Phase Microextraction and Multidimensional Gas Chromatography-Mass Spectrometry-Olfactometry.

PubMed

Soso, Simone B; Koziel, Jacek A

2016-06-25

Scent-marking is the most effective method of communication in the presence or absence of a signaler. These complex mixtures result in a multifaceted interaction triggered by the sense of smell. The objective was to identify volatile organic compound (VOC) composition and odors emitted by total marking fluid (MF) associated with Siberian tigers (Panthera tigris altaica). Siberian tiger, an endangered species, was chosen because its MF had never been analyzed. Solid phase microextraction (SPME) for headspace volatile collection combined with multidimensional gas chromatography-mass spectrometry-olfactometry for simultaneous chemical and sensory analyses were used. Thirty-two VOCs emitted from MF were identified. 2-acetyl-1-pyrroline, the sole previously identified compound responsible for the "characteristic" odor of P. tigris MF, was identified along with two additional compounds confirmed with standards (urea, furfural) and four tentatively identified compounds (3-methylbutanamine, (R)-3-methylcyclopentanone, propanedioic acid, and 3-hydroxybutanal) as being responsible for the characteristic aroma of Siberian tiger MF. Simultaneous chemical and sensory analyses improved characterization of scent-markings and identified compounds not previously reported in MF of other tiger species. This research will assist animal ecologists, behaviorists, and zookeepers in understanding how scents from specific MF compounds impact tiger and wildlife communication and improve management practices related to animal behavior. Simultaneous chemical and sensory analyses is applicable to unlocking scent-marking information for other species.

Analysis of volatile human urinary metabolome by solid-phase microextraction in combination with gas chromatography-mass spectrometry for biomarker discovery: application in a pilot study to discriminate patients with renal cell carcinoma.

PubMed

Monteiro, Márcia; Carvalho, Márcia; Henrique, Rui; Jerónimo, Carmen; Moreira, Nathalie; de Lourdes Bastos, Maria; de Pinho, Paula Guedes

2014-07-01

A new and simple analytical approach consisting of headspace-solid phase microextraction (HS-SPME) sampling coupled with gas chromatography-ion trap/mass spectrometry (GC-IT/MS) was developed to study the volatile human urinary metabolome. A central composite design (CCD) was used in the optimisation of extraction conditions. Fibre selection and evaluation of pH influence were performed using an univariate mode and the influence of other parameters, such as the time and temperature of extraction, time of incubation and salt addition, that affect the efficiency of the SPME sampling, was carried out using a CCD. With a sample volume of 2 mL, the optimal conditions in terms of total response values and reproducibility were achieved by performing analyses with a divinylbenzene/polydimethylsiloxane (DVB/PDMS) fibre, in an acidic pH (pH 2) with the addition of 0.59 g of NaCl, allowing the sample to equilibrate for 9 min and extracting at 68 °C for 24 min. The applicability of the optimised method was then tested in a pilot non-target analysis of urine samples obtained from patients with renal cell carcinoma (RCC) and healthy individuals. Chemometric unsupervised analyses performed on the volatile pattern acquired for these samples clearly showed the potential of volatile urinary metabolome to discriminate between RCC and control patients. Copyright © 2014 Elsevier Ltd. All rights reserved.

Simultaneous determination of furfural and its degradation products, furoic acid and maleic acid, in transformer oil by the reversed-phase vortex-assisted liquid-liquid microextraction followed by high-performance liquid chromatography.

PubMed

Wang, Yifan; Li, Haiyan; Yang, Zhen; Zhang, Weijie; Hua, Jia

2017-12-01

To explore why the use of furfural as a transformer oil-paper insulation aging characteristic is problematic in real world application, we developed a method for the simultaneous determination of furfural, furoic acid, and maleic acid in transformer oil by reversed-phase vortex-assisted liquid-liquid microextraction combined with high-performance liquid chromatography. The conditions for the proposed method were optimized, and the obtained extract can be directly analyzed by high-performance liquid chromatography. The detection limits (signal-to-noise ratio = 3) of the method ranged from 1.0 to 4.6 μg/L, the enrichment factors for furfural, furoic acid, maleic acid, and fumaric acid were 4.6, 25.1, 15.6, and 17.5, respectively, and the recovery rates for three analytes (fumaric acid was undetected) range from 82.1 to 106.2%. The contents of furfural, furoic acid, and maleic acid resulted from accelerated aging of transformer insulation oil-paper were measured using the present method for the first time, and the aging samples were analyzed by liquid chromatography with mass spectrometry for the identification of furoic acid and maleic acid in the aging transformer oil samples. Using the optimal method, the target products of samples at different aging time were tracked and measured. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation of a polymeric ionic liquid-coated solid-phase microextraction fiber by surface radical chain-transfer polymerization with stainless steel wire as support.

PubMed

Feng, Juanjuan; Sun, Min; Xu, Lili; Li, Jubai; Liu, Xia; Jiang, Shengxiang

2011-10-28

Polymeric 1-vinyl-3-octylimidazolium hexafluorophosphate was synthesized in situ on stainless steel wire by surface radical chain-transfer polymerization and used as sensitive coatings in solid-phase microextraction. The outer surface of the stainless steel wire was firstly coated with microstructured silver layer via silver mirror reaction and then functionalized with self-assembled monolayers of 1,8-octanedithiol, which acted as chain transfer agent in the polymerization. Coupled to gas chromatography, extraction performance of the fiber was studied with both headspace and direct-immersion modes using benzene, toluene, ethylbenzene and xylenes (BTEX), phenols and polycyclic aromatic hydrocarbon (PAHs) as model analytes. In combination with the microstructured silver layer, the PIL-coated fiber exhibited high extraction efficiency. Linear ranges for BTEX with headspace mode were in the range of 0.2-1000 μg L(-1) for benzene, and 0.1-1000 μg L(-1) for toluene, ethylbenzene and xylenes. Limits of detection (LODs) were from 0.02 to 0.05 μg L(-1). Wide linear ranges of direct-immersion mode for the extraction of several phenols and PAHs were also obtained with correlation coefficients (R) from 0.9943 to 0.9997. The proposed fiber showed good durability with long lifetime. RSDs of 56 times extraction were still in an acceptable range, from 8.85 to 22.8%. Copyright © 2011 Elsevier B.V. All rights reserved.

Sol-gel approach for fabrication of coated anodized titanium wire for solid-phase microextraction: highly efficient adsorbents for enrichment of trace polar analytes.

PubMed

Jia, Jing; Xu, Lili; Wang, Shuai; Wang, Licheng; Liu, Xia

2014-05-01

Nanotubular titania film was prepared in situ on titanium wire and was used as the fiber substrate for solid-phase microextraction (SPME) because of its high surface-to-volume ratio, easy preparation, and mechanical stability. Three different functional coatings, β-cyclodextrin (β-CD), β-cyclodextrin-co-poly(ethylenepropylene glycol) (β-CD/PEG), and polyethylene glycol (PEG)-based sorbents were chemically bonded to the nanostructured wire surface via sol-gel technology to further enhance the absorbing capability and extraction selectivity. Coupled to gas chromatography-flame ionic detection (GC-FID), the prepared SPME fibers were investigated using diverse compounds. The results indicated that the fibers showed good mechanical strength, excellent thermal stability, and wonderful capacity and selectivity to polar compounds, including polar aromatic compounds, alcohols, and ketones. Combining the superior hydrophilic property of a bonded functional molecule and the highly porous structure of a fiber coating, the prepared PEG-coated SPME fiber showed much higher adsorption affinity to ephedrine and methylephedrine than β-CD and β-CD/PEG fibers. The as-established PEG-coated SPME-GC analytical method provided excellent sensitivity (LODs, 0.004 and 0.001 ng mL(-1) for ephedrine and methylephedrine, respectively) and better linear range (0.01-2 000 μg L(-1)). In addition, it has surprising repeatability and reproducibility. Finally, the present approach was used to analyze ephedrine and methylephedrine from real urine samples, and reliable results were obtained.

Determination of bisphenol A, 4-n-nonylphenol, and 4-tert-octylphenol by temperature-controlled ionic liquid dispersive liquid-phase microextraction combined with high performance liquid chromatography-fluorescence detector.

PubMed

Zhou, Qingxiang; Gao, Yuanyuan; Xie, Guohong

2011-09-15

Present study described a simple, sensitive, and viable method for the determination of bisphenol A, 4-n-nonylphenol and 4-tert-octylphenol in water samples using temperature-controlled ionic liquid dispersive liquid-phase microextraction coupled to high performance liquid chromatography-fluorescence detector. In this experiment, 1-octyl-3-methylimidazolium hexafluorophosphate ([C(8)MIM][PF(6)]) was used as the extraction solvent, and bisphenol A, 4-n-nonylphenol and 4-tert-octylphenol were selected as the model analytes. Parameters affecting the extraction efficiency such as the volume of [C(8)MIM][PF(6)], dissolving temperature, extraction time, sample pH, centrifuging time and salting-out effect have been investigated in detail. Under the optimized conditions, good linear relationship was found in the concentration range of 1.0-100 μg L(-1) for BPA, 1.5-150 μg L(-1) for 4-NP, and 3-300 μg L(-1) for 4-OP, respectively. Limits of detection (LOD, S/N=3) were in the range of 0.23-0.48 μg L(-1). Intra day and inter day precisions (RSDs, n=6) were in the range of 4.6-5.5% and 8.5-13.3%, respectively. This method has been also successfully applied to analyze the real water samples at two different spiked concentrations and excellent results were obtained. Copyright © 2011 Elsevier B.V. All rights reserved.

Ultrasonic-assisted extraction and dispersive liquid-liquid microextraction combined with gas chromatography-mass spectrometry as an efficient and sensitive method for determining of acrylamide in potato chips samples.

PubMed

Zokaei, Maryam; Abedi, Abdol-Samad; Kamankesh, Marzieh; Shojaee-Aliababadi, Saeedeh; Mohammadi, Abdorreza

2017-11-01

In this research, for the first time, we successfully developed ultrasonic-assisted extraction and dispersive liquid-liquid microextraction combined with gas chromatography-mass spectrometry as a new, fast and highly sensitive method for determining of acrylamide in potato chips samples. Xanthydrol was used as a derivatization reagent and parameters affecting in the derivatization and microextraction steps were studied and optimized. Under optimum conditions, the calibration curves showed high levels of linearity (R 2 >0.9993) for acrylamide in the range of 2-500ngmL -1 . The relative standard deviation (RSD) for the seven analyses was 6.8%. The limit of detection (LOD) and limit of quantification (LOQ) were 0.6ngg -1 and 2ngg -1 , respectively. The UAE-DLLME-GC-MS method demonstrated high sensitivity, good linearity, recovery, and enrichment factor. The performance of the new proposed method was evaluated for the determination of acrylamide in various types of chips samples and satisfactory results were obtained. Copyright © 2017 Elsevier Ltd. All rights reserved.

Graphene-sensitized microporous membrane/solvent microextraction for the preconcentration of cinnamic acid derivatives in Rhizoma Typhonii.

PubMed

Xing, Rongrong; Hu, Shuang; Chen, Xuan; Bai, Xiaohong

2014-09-01

A novel graphene-sensitized microporous membrane/solvent microextraction method named microporous membrane/graphene/solvent synergistic microextraction, coupled with high-performance liquid chromatography and UV detection, was developed and introduced for the extraction and determination of three cinnamic acid derivatives in Rhizoma Typhonii. Several factors affecting performance were investigated and optimized, including the types of graphene and extraction solvent, concentration of graphene dispersed in octanol, sample phase pH, ionic strength, stirring rate, extraction time, extraction temperature, and sample volume. Under optimized conditions, the enrichment factors of cinnamic acid derivatives ranged from 75 to 269. Good linearities were obtained from 0.01 to 10 μg/mL for all analytes with regression coefficients between 0.9927 and 0.9994. The limits of quantification were <1 ng/mL, and satisfactory recoveries (99-104%) and precision (1.1-10.8%) were also achieved. The synergistic microextraction mechanism based on graphene sensitization was analyzed and described. The experimental results showed that the method was simple, sensitive, practical, and effective for the preconcentration and determination of cinnamic acid derivatives in Rhizoma Typhonii. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization of the aroma profile of novel Brazilian wines by solid-phase microextraction using polymeric ionic liquid sorbent coatings.

PubMed

Crucello, Juliana; Miron, Luiz F O; Ferreira, Victor H C; Nan, He; Marques, Marcia O M; Ritschel, Patricia S; Zanus, Mauro C; Anderson, Jared L; Poppi, Ronei J; Hantao, Leandro W

2018-05-28

In this study, a series of polymeric ionic liquid (PIL) sorbent coatings is evaluated for the extraction of polar volatile organic compounds (VOCs) from Brazilian wines using headspace solid-phase microextraction (HS-SPME), including samples from 'Isabella' and 'BRS Magna' cultivars-the latter was recently introduced by the Brazilian Agricultural Research Corporation - National Grape & Wine Research Center. The structurally tuned SPME coatings were compared to the commercial SPME phases, namely poly(acrylate) (PA) and divinylbenzene/carboxen/poly(dimethylsiloxane) (DVB/CAR/PDMS). The separation, detection and identification of the aroma profiles were obtained using comprehensive two-dimensional gas chromatography mass spectrometry (GC×GC-MS). The best performing PIL-based SPME fiber, namely 1-hexadecyl-3-vinylimidazolium bis[(trifluoromethyl)sulfonyl]imide with 1,12-di(3-vinylimidazolium)dodecane dibis[(trifluoromethyl)sulfonyl]imide incorporated cross-linker supported on an elastic nitinol wire, exhibited superior performance to DVB/CAR/PDMS regarding the average number of extracted peaks and extracted more polar analytes providing additional insight into the aroma profile of 'BRS Magna' wines. Four batches of wine were evaluated, namely 'Isabella' and 'BRS Magna' vintages 2015 and 2016, using highly selective PIL-based SPME coatings and enabled the detection of 350+ peaks. Furthermore, this is the first report evaluating the aroma of 'BRS Magna' wines. A hybrid approach that combined pixel-based Fisher ratio and peak table-based data comparison was used for data handling. This proof-of-concept experiment provided reliable and statistically valid distinction of wines that may guide regulation agencies to create high sample throughput protocols to screen wines exported by Brazilian vintners. Graphical abstract Highly selective extraction of wine aroma using polymeric ionic liquid.

Dispersive micro-solid phase extraction combined with dispersive liquid-liquid microextraction for speciation analysis of antimony by electrothermal vaporization inductively coupled plasma mass spectrometry

NASA Astrophysics Data System (ADS)

Chen, Shizhong; Zhu, Shengping; Lu, Dengbo

2018-01-01

A method was developed for speciation analysis of antimony by electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) after preconcentration/separation using dispersive micro-solid phase extraction (DMSPE) and dispersive liquid-liquid micro-extraction (DLLME). In DMSPE, titanium dioxide nanofibers were used for preconcentration and separation of analytes. The upper aqueous phase and elution solution from DMSPE were used for further preconcentration and separation of Sb(III) and Sb(V) by DLLME without any pre-oxidation or pre-reduction operation, respectively. The extracts from DLLME were used for ETV-ICP-MS determination with APDC as a chemical modifier. Under optimal conditions, the detection limits of this method were 0.019 and 0.025 pg mL- 1 with relative standard deviations of 5.7% and 6.9% for Sb(III) and Sb(V) (c = 1.0 ng mL- 1, n = 9), respectively. This method was applied for speciation analysis of Sb and its distribution in the tea leaves and the tea infusion, including total, suspended, soluble, organic and inorganic Sb as well as Sb(III) and Sb(V). The results showed that the contents of Sb are 62.7, 12.9 and 47.3 ng g- 1 in the tea leaves, tea residue and tea soup, respectively; those of soluble, organic, inorganic, Sb(III) and Sb(V) are 0.41, 0.11, 0.29, 0.21 and 0.07 ng mL- 1 in the tea soup, respectively. A certified reference material of tea leaves (GBW 07605) was analyzed by this method with satisfactory results.

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

Two-step microextraction combined with high performance liquid chromatographic analysis of pyrethroids in water and vegetable samples.

PubMed

Mukdasai, Siriboon; Thomas, Chunpen; Srijaranai, Supalax

2014-03-01

Dispersive liquid microextraction (DLME) combined with dispersive µ-solid phase extraction (D-µ-SPE) has been developed as a new approach for the extraction of four pyrethroids (tetramethrin, fenpropathrin, deltamethrin and permethrin) prior to the analysis by high performance liquid chromatography (HPLC) with UV detection. 1-Octanol was used as the extraction solvent in DLME. Magnetic nanoparticles (Fe3O4) functionalized with 3-aminopropyl triethoxysilane (APTS) were used as the dispersive in DLME and as the adsorbent in D-µ-SPE. The extracted pyrethroids were separated within 30 min using isocratic elution with acetonitrile:water (72:28). The factors affecting the extraction efficiency were investigated. Under the optimum conditions, the enrichment factors were in the range of 51-108. Linearity was obtained in the range 0.5-400 ng mL(-1) (tetramethrin) and 5-400 ng mL(-1) (fenpropathrin, deltamethrin and permethrin) with the correlation coefficients (R(2)) greater than 0.995. Detection limits were 0.05-2 ng mL(-1) (water samples) and 0.02-2.0 ng g(-1) (vegetable samples). The relative standard deviations of peak area varied from 1.8 to 2.5% (n=10). The extraction recoveries of the four pyrethroids in field water and vegetable samples were 91.7-104.5%. The proposed method has high potential for use as a sensitive method for determination of pyrethroid residues in water and vegetable samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Electrochemical luminescence determination of hyperin using a sol-gel@graphene luminescent composite film modified electrode for solid phase microextraction

NASA Astrophysics Data System (ADS)

Zou, Xiaojun; Shang, Fang; Wang, Sui

2017-02-01

In this paper, a novel electrochemiluminescence (ECL) sensor of sol-gel@graphene luminescent composite film modified electrode for hyperin determination was prepared using graphene (G) as solid-phase microextraction (SPME) material, based on selective preconcentration of target onto an electrode and followed by luminol ECL detection. Hyperin was firstly extracted from aqueous solution through the modified GCE. Hydrogel, electrogenerated chemiluminescence reagents, pH of working solution, extraction time and temperature and scan rate were discussed. Under the optimum conditions, the change of ECL intensity was in proportion to the concentration of hyperin in the range of 0.02-0.24 μg/mL with a detection limit of 0.01 μg/mL. This method showed good performance in stability, reproducibility and precision for the determination of hyperin.

[The study of carbonaceous adsorbent for solid-phase microextraction and the comparison with commercial device].

PubMed

Fang, R; Zhang, W; Wang, J; Zhang, K; Nai, Z

1999-09-01

The parameters governing solid-phase microextraction have been investigated, and the development of carbonaceous adsorbent for SPME is presented because it is durable and inexpensive. The time profile curves were determined for several organic pesticides having a wide range of water solubilities and the effect of salt was also investigated. The method of SPME-GC-ECD to analyse trace level of the organic pesticide in water is established by the determination of optimum parameters. The comparison with commercial SPME device shows that the carbonaceous adsorbent having been treated with physical or chemical method for SPME can get lower limits of detection than polyacrylate and polydimethylsiloxane, although there are still some work to be done to improve its precision. The results shows that this new SPME device has great application potential.

Determination of some volatile compounds in alcoholic beverage by headspace solid-phase microextraction gas chromatography - mass spectrometry

NASA Astrophysics Data System (ADS)

Schmutzer, G.; Avram, V.; Feher, I.; David, L.; Moldovan, Z.

2012-02-01

The volatile composition of alcoholic beverage was studied by headspace solid-phase microextraction (HSSPME) method and gas chromatography - mass spectrometry (GC-MS). Some volatile compounds, such as alcohols, esters, terpenes and other are mainly responsible for the flavor of fortified wines and their amounts specify the quality of the alcoholic beverages. From this perspective it is interesting to develop a rapid, selective and sensitive analytical method suitable for simultaneous quantification of the main molecules being responsible for the organoleptic characteristic of alcoholic beverages. Vermouth fortified drink was analyzed in order to characterize the volatile profile. Using the HS-SPME/GC-MS a number of twenty-six volatile compounds from a commercial market alcoholic beverage were identified. The most abundant compounds were m-thymol, o-thymol and eugenol, alongside of the ethyl ester compounds.

Identification of volatiles in leaves of Alpinia zerumbet 'Variegata' using headspace solid-phase microextraction-gas chromatography-mass spectrometry.

PubMed

Chen, Jian Yan; Ye, Zheng Mei; Huang, Tian Yi; Chen, Xiao Dan; Li, Yong Yu; Wu, Shao Hua

2014-07-01

Alpinia zerumbet 'Variegata' is an aromatic medicinal plant, its foliage producing an intense, unique fragrant odor. This study identified 46 volatile compounds in the leaf tissue of this plant using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). The major compounds included 1, 8-cineole (43.5%), p-cymene (14.7%), humulene (5.5%), camphor (5.3%), linalool (4.7%), (E)-methyl cinnamate (3.8%), gamma-cadinene (3.3%), humulene oxide II (2.1%) and a-terpineol (1.5%). The majority of the volatiles were terpenoids of which oxygenated monoterpenes were the most abundant, accounting for 57.2% of the total volatiles. Alcohols made up the largest (52.8%) and aldehydes the smallest (0.2%) portions of the volatiles. Many bioactive compounds were present in the volatiles.

Solid-Phase Microextraction Coupled to Capillary Atmospheric Pressure Photoionization-Mass Spectrometry for Direct Analysis of Polar and Nonpolar Compounds.

PubMed

Mirabelli, Mario F; Zenobi, Renato

2018-04-17

A novel capillary ionization source based on atmospheric pressure photoionization (cAPPI) was developed and used for the direct interfacing between solid-phase microextraction (SPME) and mass spectrometry (MS). The efficiency of the source was evaluated for direct and dopant-assisted photoionization, analyzing both polar (e.g., triazines and organophosphorus pesticides) and nonpolar (polycyclic aromatic hydrocarbons, PAHs) compounds. The results show that the range of compound polarity, which can be addressed by direct SPME-MS can be substantially extended by using cAPPI, compared to other sensitive techniques like direct analysis in real time (DART) and dielectric barrier discharge ionization (DBDI). The new source delivers a very high sensitivity, down to sub parts-per-trillion (ppt), making it a viable alternative when compared to previously reported and less comprehensive direct approaches.

Solid-phase microextraction method for the determination of hexanal in hazelnuts as an indicator of the interaction of active packaging materials with food aroma compounds.

PubMed

Pastorelli, S; Valzacchi, S; Rodriguez, A; Simoneau, C

2006-11-01

Fatty foods are susceptible to lipid oxidation resulting in deterioration of product quality due to the generation of off-flavours. Hexanal is a good indicator of rancidity. Therefore, a method based on solid-phase microextraction (SPME) coupled to gas chromatograph with flame ionization detection was developed to determine hexanal formation in hazelnuts during storage. Optimum conditions were as follows: carboxen-polydimethylsiloxane 75 microm fibre, extraction time 10 min, equilibrium time 10 min and equilibrium temperature 60 degrees C. The effect of oxygen scavengers on the oxidation process was also evaluated by measuring hexanal formation in hazelnuts stored with/without oxygen absorber sachets. Oxygen scavengers were shown to reduce oxidation; however, analysis of the sachet revealed that other volatile compounds from the headspace were also absorbed.

In-situ ionic liquid dispersive liquid-liquid microextraction using a new anion-exchange reagent combined Fe3O4 magnetic nanoparticles for determination of pyrethroid pesticides in water samples.

PubMed

Fan, Chen; Liang, You; Dong, Hongqiang; Ding, Guanglong; Zhang, Wenbing; Tang, Gang; Yang, Jiale; Kong, Dandan; Wang, Deng; Cao, Yongsong

2017-07-04

In this work, in-situ ionic liquid dispersive liquid-liquid microextraction combined ultrasmall Fe 3 O 4 magnetic nanoparticles was developed as a kind of pretreatment method to detect pyrethroid pesticides in water samples. New anion-exchange reagents including Na[DDTC] and Na[N(CN) 2 ] were optimized for in-situ extraction pyrethroids, which showed enhanced microextraction performance. Pyrethroids were enriched by hydrophilic ionic liquid [P 4448 ][Br] (aqueous solution, 200 μL, 0.2 mmol mL -1 ) reaction in-situ with anion-exchange reagent Na[N(CN) 2 ] (aqueous solution, 300 μL, 0.2 mmol mL -1 ) forming hydrophobic ionic liquid as extraction agent in water sample (10 mL). Ultrasmall superparamagnetic iron oxide nanoparticles (30 mg) were used to collect the mixture of ionic liquid and pyrethroids followed by elution with acetonitrile. The extraction of ionic liquid strategies was unique and efficiently fulfilled with high enrichment factors (176-213) and good recoveries (80.20-117.31%). The method was successively applied to the determination of pyrethroid pesticides in different kinds of water samples with the limits of detection ranged from 0.16 to 0.21 μg L -1 . The proposed method is actually nanometer-level microextraction (average size 80 nm) with the advantages of simplicity, rapidity, and sensitivity. Copyright © 2017 Elsevier B.V. All rights reserved.

Inorganic-organic hybrid coating material for the online in-tube solid-phase microextraction of monohydroxy polycyclic aromatic hydrocarbons in urine.

PubMed

Wang, ShuLing; Xu, Hui

2016-12-01

An inorganic-organic hybrid nanocomposite (zinc oxide/polypyrrole) that represents a novel kind of coating for in-tube solid-phase microextraction is reported. The composite coating was prepared by a facile electrochemical polymerization strategy on the inner surface of a stainless-steel tube. Based on the coated tube, a novel online in-tube solid-phase microextraction with liquid chromatography and mass spectrometry method was developed and applied for the extraction of three monohydroxy polycyclic aromatic hydrocarbons in human urine. The coating displayed good extraction ability toward monohydroxy polycyclic aromatic hydrocarbons. In addition, long lifespan, excellent stability, and good compression resistance were also obtained for the coating. The experimental conditions affecting the extraction were optimized systematically. Under the optimal conditions, the limits of detection and quantification were in the range of 0.039-0.050 and 0.130-0.167 ng/mL, respectively. Good linearity (0.2-100 ng/mL) was obtained with correlation coefficients larger than 0.9967. The repeatability, expressed as relative standard deviation, ranged between 2.5% and 9.4%. The method offered the advantage of process simplicity, rapidity, automation, and sensitivity in the analysis of human urinary monohydroxy polycyclic aromatic hydrocarbons in two different cities of Hubei province. An acceptable recovery of monohydroxy polycyclic aromatic hydrocarbons (64-122%) represented the additional attractive features of the method in real urine analysis. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Magnetic ionic liquid-based dispersive liquid-liquid microextraction technique for preconcentration and ultra-trace determination of Cd in honey.

PubMed

Fiorentini, Emiliano F; Escudero, Leticia B; Wuilloud, Rodolfo G

2018-04-19

A simple, highly efficient, batch, and centrifuge-less dispersive liquid-liquid microextraction method based on a magnetic ionic liquid (MIL-DLLME) and electrothermal atomic absorption spectrometry (ETAAS) detection was developed for ultra-trace Cd determination in honey. Initially, Cd(II) was chelated with ammonium diethyldithiophosphate (DDTP) at pH 0.5 followed by its extraction with the MIL trihexyl(tetradecyl)phosphonium tetrachloroferrate(III) ([P 6,6,6,14 ]FeCl 4 ) and acetonitrile as dispersant. The MIL phase containing the analyte was separated from the aqueous phase using only a magnet. A back-extraction procedure was applied to recover Cd from the MIL phase using diluted HNO 3 and this solution was directly injected into the graphite furnace of ETAAS instrument. An extraction efficiency of 93% and a sensitivity enhancement factor of 112 were obtained under optimal experimental conditions. The detection limit (LOD) was 0.4 ng L -1 Cd, while the relative standard deviation (RSD) was 3.8% (at 2 μg L -1 Cd and n = 10), calculated from the peak height of absorbance signals. This work reports the first application of the MIL [P 6,6,6,14 ]FeCl 4 along with the DLLME technique for the successful determination of Cd at trace levels in different honey samples. Graphical abstract Preconcentration of ultratraces of Cd in honey using a magnetic ionic liquid and dispersive liquid-liquid microextraction technique.

Characterization and semiquantitative analysis of volatiles in seedless watermelon varieties using solid-phase microextraction.

PubMed

Beaulieu, John C; Lea, Jeanne M

2006-10-04

Seedless triploid watermelons have increased in popularity since the early 1990s, and the demand for seedless fruit is on the rise. Sweetness and sugars are crucial breeding focuses for fruit quality. Volatiles also play an important role; yet, we found no literature for seedless varieties and no reports using solid-phase microextraction (SPME) in watermelon. The objective of this experiment was to identify volatile and semivolatile compounds in five seedless watermelon varieties using carboxen divinylbenzene polydimethylsiloxane solid-phase microextraction (SPME) with gas chromatography-mass spectrometry (GC-MS). Fully ripe watermelon was squeezed through miracloth to produce rapid juice extracts for immediate headspace SPME GC-MS. Aldehydes, alcohols, ketones, and one furan (2-pentyl furan, a lipid oxidation product) were recovered. On the basis of total ion count peak area, the most abundant compounds in five varieties were 3-nonen-1-ol/(E,Z)-2,6-nonadienal (16.5-28.2%), (E)-2-nonenal (10.6-22.5%), and (Z)-6-nonenal (2.0-11.3%). Hexanal was most abundant (37.7%) in one variety (Petite Perfection) [corrected] The most abundant ketone was 6-methyl-5-hepten-2-one (2.7-7.7%). Some sensory attributes reported for these compounds are melon, citrus, cucumber, orange, rose, floral, guava, violet, vegetable, green, grassy, herbaceous, pungent, fatty, sweet, and waxy. Identifying and relating these compounds to sensory attributes will allow for future monitoring of the critical flavor compounds in seedless watermelon after processing and throughout fresh-cut storage.

Speciation analysis of mercury by solid-phase microextraction and multicapillary gas chromatography hyphenated to inductively coupled plasma-time-of-flight-mass spectrometry.

PubMed

Jitaru, Petru; Adams, Freddy C

2004-11-05

This paper reports the development of an analytical approach for speciation analysis of mercury at ultra-trace levels on the basis of solid-phase microextraction and multicapillary gas chromatography hyphenated to inductively coupled plasma-time-of-flight mass spectrometry. Headspace solid-phase microextraction with a carboxen/polydimethylsyloxane fiber is used for extraction/preconcentration of mercury species after derivatization with sodium tetraethylborate and subsequent volatilization. Isothermal separation of methylmercury (MeHg), inorganic mercury (Hg2+) and propylmercury (PrHg) used as internal standard is achieved within a chromatographic run below 45 s without the introduction of spectral skew. Method detection limits (3 x standard deviation criteria) calculated for 10 successive injections of the analytical reagent blank are 0.027 pg g(-1) (as metal) for MeHg and 0.27 pg g(-1) for Hg2+. The repeatability (R.S.D., %) is 3.3% for MeHg and 3.8% for Hg2+ for 10 successive injections of a standard mixture of 10pg. The method accuracy for MeHg and total mercury is validated through the analysis of marine and estuarine sediment reference materials. A comparison of the sediment data with those obtained by a purge-and-trap injection (PTI) method is also addressed. The analytical procedure is illustrated with some results for the ultra-trace level analysis of ice from Antarctica for which the accuracy is assessed by spike recovery experiments.

Ionic-liquid-mediated poly(dimethylsiloxane)- grafted carbon nanotube fiber prepared by the sol-gel technique for the head space solid-phase microextraction of methyl tert-butyl ether using GC.

PubMed

Vatani, Hossein; Yazdi, Ali Sarafraz

2014-01-01

A headspace solid-phase microextraction method was developed for the preconcentration and extraction of methyl tert-butyl ether. An ionic-liquid-mediated multiwalled carbon nanotube-poly(dimethylsiloxane) hybrid coating, which was prepared by covalent functionalization of multiwalled carbon nanotubes with hydroxyl-terminated poly(dimethylsiloxane) using the sol-gel technique, was used as solid-phase microextraction adsorbent. This innovative fiber exhibited a highly porous surface structure, high thermal stability (at least 320°C) and long lifespan (over 210 uses). Potential factors affecting the extraction efficiency were optimized. Under the optimum conditions, the method LOD (S/N = 3) was 0.007 ng/mL and the LOQ (S/N = 10) was 0.03 ng/mL. The calibration curve was linear in the range of 0.03-200 ng/mL. The RSDs for one fiber (repeatability, n = 5) at three different concentrations (0.05, 1, and 150 ng/mL) were 5.1, 4.2, and 4.6% and for the fibers obtained from different batches (reproducibility, n = 3) were 6.5, 5.9, and 6.3%, respectively. The developed method was successfully applied to the determination of methyl tert-butyl ether in different real water samples on three consecutive days. The relative recoveries for the spiked samples with 0.05, 1, and 150 ng/mL were between 94-104%. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rapid in situ growth of oriented titanium-nickel oxide composite nanotubes arrays coated on a nitinol wire as a solid-phase microextraction fiber coupled to HPLC-UV.

PubMed

Zhen, Qi; Zhang, Min; Song, Wenlan; Wang, Huiju; Wang, Xuemei; Du, Xinzhen

2016-10-01

An oriented titanium-nickel oxide composite nanotubes coating was in situ grown on a nitinol wire by direct electrochemical anodization in ethylene glycol with ammonium fluoride and water for the first time. The morphology and composition of the resulting coating showed that the anodized nitinol wire provided a titania-rich coating. The titanium-nickel oxide composite nanotubes coated fiber was used for solid-phase microextraction of different aromatic compounds coupled to high-performance liquid chromatography with UV detection. The titanium-nickel oxide composite nanotubes coating exhibited high extraction capability, good selectivity, and rapid mass transfer for weakly polar UV filters. Thereafter the important parameters affecting extraction efficiency were investigated for solid-phase microextraction of UV filters. Under the optimized conditions, the calibration curves were linear in the range of 0.1-300 μg/L for target UV filters with limits of detection of 0.019-0.082 μg/L. The intraday and interday precision of the proposed method with the single fiber were 5.3-7.2 and 5.9-7.9%, respectively, and the fiber-to-fiber reproducibility ranged from 6.3 to 8.9% for four fibers fabricated in different batches. Finally, its applicability was evaluated by the extraction and determination of target UV filters in environmental water samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Analytical methods for the assessment of endocrine disrupting chemical exposure during human fetal and lactation stages: a review.

PubMed

Jiménez-Díaz, I; Vela-Soria, F; Rodríguez-Gómez, R; Zafra-Gómez, A; Ballesteros, O; Navalón, A

2015-09-10

In the present work, a review of the analytical methods developed in the last 15 years for the determination of endocrine disrupting chemicals (EDCs) in human samples related with children, including placenta, cord blood, amniotic fluid, maternal blood, maternal urine and breast milk, is proposed. Children are highly vulnerable to toxic chemicals in the environment. Among these environmental contaminants to which children are at risk of exposure are EDCs -substances able to alter the normal hormone function of wildlife and humans-. The work focuses mainly on sample preparation and instrumental techniques used for the detection and quantification of the analytes. The sample preparation techniques include, not only liquid-liquid extraction (LLE) and solid-phase extraction (SPE), but also modern microextraction techniques such as extraction with molecular imprinted polymers (MIPs), stir-bar sorptive extraction (SBSE), hollow-fiber liquid-phase microextraction (HF-LPME), dispersive liquid-liquid microextraction (DLLME), matrix solid phase dispersion (MSPD) or ultrasound-assisted extraction (UAE), which are becoming alternatives in the analysis of human samples. Most studies focus on minimizing the number of steps and using the lowest solvent amounts in the sample treatment. The usual instrumental techniques employed include liquid chromatography (LC), gas chromatography (GC) mainly coupled to tandem mass spectrometry. Multiresidue methods are being developed for the determination of several families of EDCs with one extraction step and limited sample preparation. Copyright © 2015 Elsevier B.V. All rights reserved.

Solid phase microextraction for active or passive sampling of methyl bromide during fumigations

USDA-ARS?s Scientific Manuscript database

The high diffusivity and volatility of methyl bromide make it an ideal compound for Solid Phase Micro Extraction (SPME)-based sampling of air prior to gas-chromatographic quantifications. SPME fibers can be used as active methyl bromide samplers, with high capacities and an equilibrium time of 1-2 m...

Preparation of a novel hyperbranched carbosilane-silica hybrid coating for trace amount detection by solid phase microextraction/gas chromatography.

PubMed

Chen, Guowen; Li, Wenjie; Zhang, Chen; Zhou, Chuanjian; Feng, Shengyu

2012-09-21

Phenyl-ended hyperbranched carbosilane (HBC) is synthesized and immobilized onto the inner wall of a fused silica capillary column using a sol-gel process. The hybrid coating layer formed is used as a stationary phase for gas chromatography (GC) and as an adsorption medium for solid phase microextraction (SPME). Trifluoroacetic acid, as a catalyst in this process, helps produce a homogeneous hybrid coating layer. This result is beneficial for better column chromatographic performances, such as high efficiency and high resolution. Extraction tests using the novel hybrid layer show an extraordinarily large adsorption capacity and specific adsorption behavior for aromatic compounds. A 1 ppm trace level detectability is obtained with the SPME/GC work model when both of the stationary phase and adsorption layer bear a hyperbranched structure. A large amount of phenyl groups and a low viscosity of hyperbranched polymers contribute to these valuable properties, which are important to environment and safety control, wherein detection sensitivity and special adsorption behavior are usually required. Copyright © 2012 Elsevier B.V. All rights reserved.

Solid-phase microextraction and chiral HPLC analysis of ibuprofen in urine.

PubMed

de Oliveira, Anderson Rodrigo Moraes; Cesarino, Evandro José; Bonato, Pierina Sueli

2005-04-25

A simple and rapid solid-phase microextraction method was developed for the enantioselective analysis of ibuprofen in urine. The sampling was made with a polydimethylsiloxane-divinylbenzene coated fiber immersed in the liquid sample. After desorptioning from the fiber, ibuprofen enantiomers were analyzed by HPLC using a Chiralpak AD-RH column and UV detection. The mobile phase was made of methanol-pH 3.0 phosphoric acid solution (75:25, v/v), at a flow rate of 0.45 mL/min. The mean recoveries of SPME were 19.8 and 19.1% for (-)-R-ibuprofen and (+)-(S)-ibuprofen, respectively. The method was linear at the range of 0.25-25 microg/mL. Within-day and between-day assay precision and accuracy were below 15% for both ibuprofen enantiomers at concentrations of 0.75, 7.5 and 20 microg/mL. The method was tested with urine quality control samples and human urine fractions after administration of 200 mg rac-ibuprofen.

Determination of free and deconjugated testosterone and epitestosterone in urine using SPME and LC-MS/MS.

PubMed

Zhan, Yanwei; Musteata, Florin M; Basset, Fabien A; Pawliszyn, Janusz

2011-01-01

A thin sheet of polydimethylsilosane membrane was used as an extraction phase for solid-phase microextraction. Compared with fiber or rod solid-phase microextraction geometries, the thin film exhibited much higher extraction capacity without sacrificing extraction time due to its higher area-to-volume ratio. The analytical method involved direct extraction of unconjugated testosterone (T) and epitestosterone (ET) followed by separation on a C18 column and detection by selected reaction monitoring in positive ionization mode. The limit of detection was 1 ng/l for both T and ET. After method validation, free (unconjugated) T and ET were extracted and quantified in real samples. Since T and ET are extensively metabolized, the proposed method was also applied to extract the steroids after enzymatic deconjugation of urinary-excreted steroid glucuronides. The proposed method allows quantification of both conjugated and unconjugated steroids, and revealed that there was a change in the ratio of T to ET after enzymatic deconjugation, indicating different rates of metabolism.

Determination of some aldehydes by using solid-phase microextraction and high-performance liquid chromatography with UV detection.

PubMed

Kumar, Ashwini; Singh, Baldev; Malik, Ashok Kumar; Tiwary, Dhananjay K

2007-01-01

A new approach has been developed for the extraction and determination of aldehydes such as veratraldehyde, m-nitrobenzaldehyde, cinnamaldehyde, benzaldehyde, and p-chlorobenzaldehyde by using solid-phase microextraction (SPME) and high-performance liquid chromatography with UV detection (HPLC/UV). The method involves adsorption of the aldehydes on polydimethylsiloxane/divinylbenzene-coated fiber, followed by desorption in the desorption chamber of the SPME-HPLC interface, using acetonitrile-water (70 + 30) as the mobile phase; UV detection was at 254 nm. A good separation of 5 aldehydes was obtained on a C18 column. The detection limits of veratraldehyde, m-nitrobenzaldehyde, cinnamaldehyde, benzaldehyde, and p-chlorobenzaldehyde are 25, 41, 13, 12, and 11 pg/mL, respectively, which are about 100 times better than the detection limits for other SPME methods using gas chromatography. The proposed method was validated by determining benzaldehyde in bitter almonds and cinnamaldehyde in cinnamon bark. The recoveries of the 5 analytes were determined by analysis of spiked drinking water.

Development of ultrasound-assisted emulsification microextraction based on solidification of a floating organic droplet for determination of organochlorine pesticides in water samples.

PubMed

Shu, Bin; Yang, Zhaoguang; Lee, Hsiaowan; Qiu, Bo; Li, Haipu

2016-02-01

An ultrasound-assisted emulsification microextraction based on the solidification of a floating organic droplet followed by gas chromatography with electron capture detection was developed for the simultaneous determination of 13 organochlorine pesticides in water samples. In the proposed method, ultrasound was applied to achieve the emulsification without addition of any dispersive solvent. In consequence, the volume of extraction phase remained unaffected by the ion strength of aqueous phase and high extraction recoveries were obtained. It was also found that dilution of the floating phase with acetone was necessary for preventing peak splitting in chromatogram. Under optimal conditions, the proposed method provided good sensitivity (the detection limits of organochlorine pesticides ranged from 1.3 to 3.9 ng/L) and good repeatability of extraction (below 6.5%, n = 5). The recoveries in reservoir and river water samples were between 75.8% and 96.9%. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ultrafast Screening and Quantitation of Pesticides in Food and Environmental Matrices by Solid-Phase Microextraction-Transmission Mode (SPME-TM) and Direct Analysis in Real Time (DART).

PubMed

Gómez-Ríos, Germán Augusto; Gionfriddo, Emanuela; Poole, Justen; Pawliszyn, Janusz

2017-07-05

The direct interface of microextraction technologies to mass spectrometry (MS) has unquestionably revolutionized the speed and efficacy at which complex matrices are analyzed. Solid Phase Micro Extraction-Transmission Mode (SPME-TM) is a technology conceived as an effective synergy between sample preparation and ambient ionization. Succinctly, the device consists of a mesh coated with polymeric particles that extracts analytes of interest present in a given sample matrix. This coated mesh acts as a transmission-mode substrate for Direct Analysis in Real Time (DART), allowing for rapid and efficient thermal desorption/ionization of analytes previously concentrated on the coating, and dramatically lowering the limits of detection attained by sole DART analysis. In this study, we present SPME-TM as a novel tool for the ultrafast enrichment of pesticides present in food and environmental matrices and their quantitative determination by MS via DART ionization. Limits of quantitation in the subnanogram per milliliter range can be attained, while total analysis time does not exceed 2 min per sample. In addition to target information obtained via tandem MS, retrospective studies of the same sample via high-resolution mass spectrometry (HRMS) were accomplished by thermally desorbing a different segment of the microextraction device.

One-calibrant kinetic calibration for on-site water sampling with solid-phase microextraction.

PubMed

Ouyang, Gangfeng; Cui, Shufen; Qin, Zhipei; Pawliszyn, Janusz

2009-07-15

The existing solid-phase microextraction (SPME) kinetic calibration technique, using the desorption of the preloaded standards to calibrate the extraction of the analytes, requires that the physicochemical properties of the standard should be similar to those of the analyte, which limited the application of the technique. In this study, a new method, termed the one-calibrant kinetic calibration technique, which can use the desorption of a single standard to calibrate all extracted analytes, was proposed. The theoretical considerations were validated by passive water sampling in laboratory and rapid water sampling in the field. To mimic the variety of the environment, such as temperature, turbulence, and the concentration of the analytes, the flow-through system for the generation of standard aqueous polycyclic aromatic hydrocarbons (PAHs) solution was modified. The experimental results of the passive samplings in the flow-through system illustrated that the effect of the environmental variables was successfully compensated with the kinetic calibration technique, and all extracted analytes can be calibrated through the desorption of a single calibrant. On-site water sampling with rotated SPME fibers also illustrated the feasibility of the new technique for rapid on-site sampling of hydrophobic organic pollutants in water. This technique will accelerate the application of the kinetic calibration method and also will be useful for other microextraction techniques.

Solid-phase microfibers based on polyethylene glycol modified single-walled carbon nanotubes for the determination of chlorinated organic carriers in textiles.

PubMed

Zhang, Wei-Ya; Sun, Yin; Wang, Cheng-Ming; Wu, Cai-Ying

2011-09-01

Based on polyethylene glycol modified single-walled carbon nanotubes, a novel sol-gel fiber coating was prepared and applied to the headspace microextraction of chlorinated organic carriers (COCs) in textiles by gas chromatography-electron capture detection. The preparation of polyethylene glycol modified single-walled carbon nanotubes and the sol-gel fiber coating process was stated and confirmed by infrared spectra, Raman spectroscopy, and scanning electron microscopy. Several parameters affecting headspace microextraction, including extraction temperature, extraction time, salting-out effect, and desorption time, were optimized by detecting 11 COCs in simulative sweat samples. Compared with the commercial solid-phase microextraction fibers, the sol-gel polyethylene glycol modified single-walled carbon nanotubes fiber showed higher extraction efficiency, better thermal stability, and longer life span. The method detection limits for COCs were in the range from 0.02 to 7.5 ng L(-1) (S/N = 3). The linearity of the developed method varied from 0.001 to 50 μg L(-1) for all analytes, with coefficients of correlation greater than 0.974. The developed method was successfully applied to the analysis of trace COCs in textiles, the recoveries of the analytes indicated that the developed method was considerably useful for the determination of COCs in ecological textile samples.

A new chemical tool for absinthe producers, quantification of α/β-thujone and the bitter components in Artemisia absinthium.

PubMed

Bach, Benoit; Cleroux, Marilyn; Saillen, Mayra; Schönenberger, Patrik; Burgos, Stephane; Ducruet, Julien; Vallat, Armelle

2016-12-15

The concentrations of α/β-thujone and the bitter components of Artemisia absinthium were quantified from alcoholic wormwood extracts during four phenological stages of their harvest period. A solid-phase micro-extraction method coupled to gas chromatography-mass spectrometry was used to determine the concentration of the two isomeric forms of thujone. In parallel, the combination of ultra-high pressure liquid chromatography and high resolution mass spectrometry allowed to quantify the compounds absinthin, artemisetin and dihydro-epi-deoxyarteannuin B. This present study aimed at helping absinthe producers to determine the best harvesting period. Copyright © 2016 Elsevier Ltd. All rights reserved.

New-generation bar adsorptive microextraction (BAμE) devices for a better eco-user-friendly analytical approach-Application for the determination of antidepressant pharmaceuticals in biological fluids.

PubMed

Ide, A H; Nogueira, J M F

2018-05-10

The present contribution aims to design new-generation bar adsorptive microextraction (BAμE) devices that promote an innovative and much better user-friendly analytical approach. The novel BAμE devices were lab-made prepared having smaller dimensions by using flexible nylon-based supports (7.5 × 1.0 mm) coated with convenient sorbents (≈ 0.5 mg). This novel advance allows effective microextraction and back-extraction ('only single liquid desorption step') stages as well as interfacing enhancement with the instrumental systems dedicated for routine analysis. To evaluate the achievements of these improvements, four antidepressant agents (bupropion, citalopram, amitriptyline and trazodone) were used as model compounds in aqueous media combined with liquid chromatography (LC) systems. By using an N-vinylpyrrolidone based-polymer phase good selectivity and efficiency were obtained. Assays performed on 25 mL spiked aqueous samples, yielded average recoveries in between 67.8 ± 12.4% (bupropion) and 88.3 ± 12.1% (citalopram), under optimized experimental conditions. The analytical performance also showed convenient precision (RSD < 12%) and detection limits (50 ng L -1 ), as well as linear dynamic ranges (160-2000 ng L -1 ) with suitable determination coefficients (r 2  > 0.9820). The application of the proposed analytical approach on biological fluids showed negligible matrix effects by using the standard addition methodology. From the data obtained, the new-generation BAμE devices presented herein provide an innovative and robust analytical cycle, are simple to prepare, cost-effective, user-friendly and compatible with the current LC autosampler systems. Furthermore, the novel devices were designed to be disposable and used together with negligible amounts of organic solvents (100 μL) during back-extraction, in compliance with the green analytical chemistry principles. In short, the new-generation BAμE devices showed to be an eco-user-friendly approach for trace analysis of priority compounds in biological fluids and a versatile alternative over other well-stablished sorption-based microextraction techniques. Copyright © 2018 Elsevier B.V. All rights reserved.

A new supramolecular based liquid solid microextraction method for preconcentration and determination of trace bismuth in human blood serum and hair samples by electrothermal atomic absorption spectrometry.

PubMed

Kahe, Hadi; Chamsaz, Mahmoud

2016-11-01

A simple and reliable supramolecule-aggregated liquid solid microextraction method is described for preconcentration and determination of trace amounts of bismuth in water as well as human blood serum and hair samples. Catanionic microstructures of cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) surfactants, dissolved in deionized water/propanol, are used as a green solvent to extract bismuth (III)-diethyldithiocarbamate complexes by dispersive microextraction methodology. The extracted solid phase is easily removed and dissolved in 50 μL propanol for subsequent measurement by electrothermal atomic absorption spectrometry (ET-AAS). The procedure benefits the merits of supramolecule aggregates' properties and dispersive microextraction technique using water as the main component of disperser solvent, leading to direct interaction with analyte. Phase separation behavior of extraction solvent and different parameters influencing the extraction efficiency of bismuth ion such as salt concentration, pH, centrifugation time, amount of chelating agent, SDS:CTAB mole ratio, and solvent amounts were thoroughly optimized. Under the optimal experimental conditions, the calibration curve was linear in the range of 0.3-6 μg L -1 Bi (III) with a limit of detection (LOD) of 0.16 μg L -1 (S/N = 3). The relative standard deviations (RSD) of determination were obtained to be 5.1 and 6.2 % for 1 and 3 μg L -1 of Bi (III), respectively. The developed method was successfully applied as a sensitive and accurate technique for determination of bismuth ion in human blood serum, hair samples, and a certified reference material.

Suitable conditions for liquid-phase microextraction using solidification of a floating drop for extraction of fat-soluble vitamins established using an orthogonal array experimental design.

PubMed

Sobhi, Hamid Reza; Yamini, Yadollah; Esrafili, Ali; Abadi, Reza Haji Hosseini Baghdad

2008-07-04

A simple, rapid and efficient microextraction method for the extraction and determination of some fat-soluble vitamins (A, D2, D3) in aqueous samples was developed. For the first time orthogonal array designs (OADs) were employed to screen the liquid-phase microextraction (LPME) method in which few microliters of 1-undecanol were delivered to the surface of the aqueous sample and it was agitated for a selected time. Then sample vial was cooled by inserting it into an ice bath for 5 min. The solidified solvent was transferred into a suitable vial and immediately melted. Then, the extract was directly injected into a high-performance liquid chromatography (HPLC) for analysis. Several factors affecting the microextraction efficiency such as sample solution temperature, stirring speed, volume of the organic solvent, ionic strength and extraction time were investigated and screened using an OA16 (4(5)) matrix. Under the best conditions (temperature, 55 degrees C; stirring speed, 1000 rpm; the volume of extracting solvent, 15.0 microL; no salt addition and extraction time, 60 min), detection limits of the method were in the range of 1.0-3.5 microgL(-1). The relative standard deviations (RSDs) to determine the vitamins at microg L(-1) levels by applying the proposed method varied in the range of 5.1-10.7%. Dynamic linear ranges of 5-500 mugL(-1) with good correlation coefficients (0.9984

Role of precursors and coating polymers in sol-gel chemistry toward enhanced selectivity and efficiency in solid phase microextraction.

PubMed

Bagheri, Habib; Piri-Moghadam, Hamed; Ahdi, Tayebeh

2012-09-12

To evaluate the selectivity and efficiency of solid phase microextraction (SPME) fiber coatings, synthesized by sol-gel technology, roles of precursors and coating polymers were extensively investigated. An on-line combination of capillary microextraction (CME) technique and high performance liquid chromatography (HPLC) was set up to perform the investigation. Ten different fiber coatings were synthesized in which five of them contained only the precursor and the rests were prepared using both the precursor and coating polymer. All the coatings were chemically bonded to the inner surface of copper tubes, intended to be used as the CME device and already functionalized by self-assembly monolayers of 3-(mercaptopropyl)trimethoxysilane (3MPTMOS). The selected precursors included tetramethoxysilane (TMOS), 3-(trimethoxysilyl)propylmethacrylate (TMSPMA), 3-(triethoxysilyl)-propylamine (TMSPA), 3MPTMOS, [3-(2,3-epoxypropoxy)-propyl]-trimethoxysilane (EPPTMOS) while poly(ethyleneglycol) (PEG) was chosen as the coating polymer. The effects of different precursors on the extraction efficiency and selectivity, was studied by selecting a list of compounds ranging from non-polar to polar ones, i.e. polycyclic aromatic hydrocarbon, herbicides, estrogens and triazines. The results from CME-HPLC analysis revealed that there is no significant difference between precursors, except TMOS, in which has the lowest extraction efficiency. Most of the selected precursors have rather similar interactions toward the selected analytes which include Van der Walls, dipole-dipole and hydrogen bond while TMOS has only dipole-dipole interaction and therefore the least efficiency. TMOS is silica but the other sorbents are organically modified silica (ORMOSIL). Our investigation revealed that it is rather impossible to prepare a selective coating using conventional sol-gel methodologies. The comparison study performed among the fiber coatings contained only a precursor and those synthesized by a precursor along with coating polymer proved that the extraction efficiency obtained for all coatings are the same. This is an indication that by selecting the appropriate precursor there is no need to use any coating polymer. In overall, a fiber coating in sol-gel process could be synthesize with no coating polymer which leads to faster, easier, cheaper and more controllable synthesis. Copyright © 2012 Elsevier B.V. All rights reserved.

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.

Simultaneous determination of polycyclic aromatic hydrocarbons and their chlorination by-products in drinking water and the coatings of water pipes by automated solid-phase microextraction followed by gas chromatography-mass spectrometry.

PubMed

Tillner, Jocelyn; Hollard, Caroline; Bach, Cristina; Rosin, Christophe; Munoz, Jean-François; Dauchy, Xavier

2013-11-08

In this study, an automated method for the simultaneous determination of polycyclic aromatic hydrocarbons (PAHs) and their chlorination by-products in drinking water was developed based on online solid-phase microextraction-gas chromatography-mass spectrometry. The main focus was the optimisation of the solid-phase microextraction step. The influence of the agitation rate, type of fibre, desorption time, extraction time, extraction temperature, desorption temperature, and solvent addition was examined. The method was developed and validated using a mixture of 17 PAHs, 11 potential chlorination by-products (chlorinated and oxidised PAHs) and 6 deuterated standards. The limit of quantification was 10 ng/L for all target compounds. The validated method was used to analyse drinking water samples from three different drinking water distribution networks and the presumably coal tar-based pipe coatings of two pipe sections. A number of PAHs were detected in all three networks although individual compositions varied. Several PAH chlorination by-products (anthraquinone, fluorenone, cyclopenta[d,e,f]phenanthrenone, 3-chlorofluoranthene, and 1-chloropyrene) were also found, their presence correlating closely with that of their respective parent compounds. Their concentrations were always below 100 ng/L. In the coatings, all PAHs targeted were detected although concentrations varied between the two coatings (76-12,635 mg/kg and 12-6295 mg/kg, respectively). A number of chlorination by-products (anthraquinone, fluorenone, cyclopenta[d,e,f]phenanthrenone, 3-chlorofluoranthene, and 1-chloropyrene) were also detected (from 40 to 985 mg/kg), suggesting that the reaction of PAHs with disinfectant agents takes place in the coatings and not in the water phase after migration. Copyright © 2013 Elsevier B.V. All rights reserved.

Magnetic stirrer induced dispersive ionic-liquid microextraction for the determination of vanadium in water and food samples prior to graphite furnace atomic absorption spectrometry.

PubMed

Naeemullah; Kazi, Tasneem Gul; Tuzen, Mustafa

2015-04-01

A new dispersive liquid-liquid microextraction, magnetic stirrer induced dispersive ionic-liquid microextraction (MS-IL-DLLME) was developed to quantify the trace level of vanadium in real water and food samples by graphite furnace atomic absorption spectrometry (GFAAS). In this extraction method magnetic stirrer was applied to obtained a dispersive medium of 1-butyl-3-methylimidazolium hexafluorophosphate [C4MIM][PF6] in aqueous solution of (real water samples and digested food samples) to increase phase transfer ratio, which significantly enhance the recovery of vanadium - 4-(2-pyridylazo) resorcinol (PAR) chelate. Variables having vital role on desired microextraction methods were optimised to obtain the maximum recovery of study analyte. Under the optimised experimental variables, enhancement factor (EF) and limit of detection (LOD) were achieved to be 125 and 18 ng L(-1), respectively. Validity and accuracy of the desired method was checked by analysis of certified reference materials (SLRS-4 Riverine water and NIST SRM 1515 Apple leaves). The relative standard deviation (RSD) for 10 replicate determinations at 0.5 μg L(-1) of vanadium level was found to be <5.0%. This method was successfully applied to real water and acid digested food samples. Copyright © 2014 Elsevier Ltd. All rights reserved.

Determination of acrylamide in brewed coffee and coffee powder using polymeric ionic liquid-based sorbent coatings in solid-phase microextraction coupled to gas chromatography-mass spectrometry.

PubMed

Cagliero, Cecilia; Ho, Tien D; Zhang, Cheng; Bicchi, Carlo; Anderson, Jared L

2016-06-03

This study describes a simple and rapid sampling method employing a polymeric ionic liquid (PIL) sorbent coating in direct immersion solid-phase microextraction (SPME) for the trace-level analysis of acrylamide in brewed coffee and coffee powder. The crosslinked PIL sorbent coating demonstrated superior sensitivity in the extraction of acrylamide compared to all commercially available SPME coatings. A spin coating method was developed to evenly distribute the PIL coating on the SPME support and reproducibly produce fibers with a large film thickness. Ninhydrin was employed as a quenching reagent during extraction to inhibit the production of interfering acrylamide. The PIL fiber produced a limit of quantitation for acrylamide of 10μgL(-1) and achieved comparable results to the ISO method in the analysis of six coffee powder samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Solid phase microextraction device using aerogel

DOEpatents

Miller, Fred S.; Andresen, Brian D.

2005-06-14

A sample collection substrate of aerogel and/or xerogel materials bound to a support structure is used as a solid phase microextraction (SPME) device. The xerogels and aerogels may be organic or inorganic and doped with metals or other compounds to target specific chemical analytes. The support structure is typically formed of a glass fiber or a metal wire (stainless steel or kovar). The devices are made by applying gel solution to the support structures and drying the solution to form aerogel or xerogel. Aerogel particles may be attached to the wet layer before drying to increase sample collection surface area. These devices are robust, stable in fields of high radiation, and highly effective at collecting gas and liquid samples while maintaining superior mechanical and thermal stability during routine use. Aerogel SPME devices are advantageous for use in GC/MS analyses due to their lack of interfering background and tolerance of GC thermal cycling.

Method for preparing a solid phase microextraction device using aerogel

DOEpatents

Miller, Fred S [Bethel Island, CA; Andresen, Brian D [Livermore, CA

2006-10-24

A sample collection substrate of aerogel and/or xerogel materials bound to a support structure is used as a solid phase microextraction (SPME) device. The xerogels and aerogels may be organic or inorganic and doped with metals or other compounds to target specific chemical analytes. The support structure is typically formed of a glass fiber or a metal wire (stainless steel or kovar). The devices are made by applying gel solution to the support structures and drying the solution to form aerogel or xerogel. Aerogel particles may be attached to the wet layer before drying to increase sample collection surface area. These devices are robust, stable in fields of high radiation, and highly effective at collecting gas and liquid samples while maintaining superior mechanical and thermal stability during routine use. Aerogel SPME devices are advantageous for use in GC/MS analyses due to their lack of interfering background and tolerance of GC thermal cycling.

Solid-phase microextraction of benzimidazole fungicides in environmental liquid samples and HPLC-fluorescence determination.

PubMed

López Monzón, A; Vega Moreno, D; Torres Padrón, M E; Sosa Ferrera, Z; Santana Rodríguez, J J

2007-03-01

Solid-phase microextraction (SPME) coupled with high-performance liquid chromatography (HPLC) with fluorescence detection was optimized for extraction and determination of four benzimidazole fungicides (benomyl, carbendazim, thiabendazole, and fuberidazole) in water. We studied extraction and desorption conditions, for example fiber type, extraction time, ionic strength, extraction temperature, and desorption time to achieve the maximum efficiency in the extraction. Results indicate that SPME using a Carboxen-polydimethylsiloxane 75 microm (CAR-PDMS) fiber is suitable for extraction of these types of compound. Final analysis of benzimidazole fungicides was performed by HPLC with fluorescence detection. Recoveries ranged from 80.6 to 119.6 with RSDs below 9% and limits of detection between 0.03 and 1.30 ng mL-1 for the different analytes. The optimized procedure was applied successfully to the determination of benzimidazole fungicides mixtures in environmental water samples (sea, sewage, and ground water).

Solid-phase microextraction coupled with high-performance liquid chromatography for the determination of phenylurea herbicides in aqueous samples.

PubMed

Lin, Hsin-Hang; Sung, Yu-Hsiang; Huang, Shang-Da

2003-09-12

Solid-phase microextraction coupled with high-performance liquid chromatography was successfully applied to the analysis of nine phenylurea herbicides (metoxuron, monuron, chlorotoluron, isoproturon, monolinuron, metobromuron, buturon, linuron, and chlorbromuron). Polydimethylsiloxane-divinylbenzene (PDMS-DVB, 60 microm) and Carbowax-templated resin (CW-TPR, 50 microm) fibers were selected from four commercial fibers for further study because of their better extraction efficiencies. The parameters of the desorption procedure were studied and optimized. The effects of the properties of analytes and fiber coatings, carryover, duration and temperature of absorption, pH, organic solvent and ionic strength of samples were also investigated. External calibration with an aqueous standard can be used for the analysis of environmental samples (lake water) using either PDMS-DVB or CW-TPR fibers. Good precisions (1.0-5.9%) are achieved for this method, and the detection limits are at the level of 0.5-5.1 ng/ml.

Coupling solid-phase microextraction and high-performance liquid chromatography for direct and sensitive determination of halogenated fungicides in wine.

PubMed

Millán, S; Sampedro, M C; Unceta, N; Goicolea, M A; Rodríguez, E; Barrio, R J

2003-05-02

A solid-phase microextraction (SPME) method coupled to high-performance liquid chromatography with diode array detection (HPLC-DAD) for the analysis of six organochlorine fungicides (nuarimol, triadimenol, triadimefon, folpet, vinclozolin and penconazole) in wine was developed. For this purpose, polydimethylsiloxane-divinylbenzene-coated fibers were utilized and all factors affecting throughput, precision, and accuracy of the SPME method were investigated and optimized. These factors include: matrix influence, extraction and desorption time, percentage of ethanol, pH, salt effect and desorption mode. The performed analytical procedure showed detectability ranging from 4 to 27 microg l(-1) and precision from 2.4 to 14.2% (as intra-day relative standard deviation, RSD) and 4.7-25.7% (as inter-day RSD) depending on the fungicide. The results demonstrate the suitability of the SPME-HPLC-DAD method to analyze these organochlorine fungicides in red wine.

Carboxylated multiwalled carbon nanotubes/polydimethylsiloxane, a new coating for 96-blade solid-phase microextraction for determination of phenolic compounds in water.

PubMed

Kueseng, Pamornrat; Pawliszyn, Janusz

2013-11-22

A new thin-film, carboxylated multiwalled carbon nanotubes/polydimethylsiloxane (MWCNTs-COOH/PDMS) coating was developed for 96-blade solid-phase microextraction (SPME) system followed by high performance liquid chromatography with ultraviolet detection (HPLC-UV). The method provided good extraction efficiency (64-90%) for three spiked levels, with relative standard deviations (RSD)≤6%, and detection limits between 1 and 2 μg/L for three phenolic compounds. The MWCNTs-COOH/PDMS 96-blade SPME system presents advantages over traditional methods due to its simplicity of use, easy coating preparation, low cost and high sample throughput (2.1 min per sample). The developed coating is reusable for a minimum of 110 extractions with good extraction efficiency. The coating provided higher extraction efficiency (3-8 times greater) than pure PDMS coatings. Copyright © 2013 Elsevier B.V. All rights reserved.

Characterization of aroma compounds in apple cider using solvent-assisted flavor evaporation and headspace solid-phase microextraction.

PubMed

Xu, Yan; Fan, Wenlai; Qian, Michael C

2007-04-18

The aroma-active compounds in two apple ciders were identified using gas chromatography-olfactometry (GC-O) and GC-mass spectrometry (MS) techniques. The volatile compounds were extracted using solvent-assisted flavor evaporation (SAFE) and headspace solid-phase microextraction (HS-SPME). On the basis of odor intensity, the most important aroma compounds in the two apple cider samples were 2-phenylethanol, butanoic acid, octanoic acid, 2-methylbutanoic acid, 2-phenylethyl acetate, ethyl 2-methylbutanoate, ethyl butanoate, ethyl hexanoate, 4-ethylguaiacol, eugenol, and 4-vinylphenol. Sulfur-containing compounds, terpene derivatives, and lactones were also detected in ciders. Although most of the aroma compounds were common in both ciders, the aroma intensities were different. Comparison of extraction techniques showed that the SAFE technique had a higher recovery for acids and hydroxy-containing compounds, whereas the HS-SPME technique had a higher recovery for esters and highly volatile compounds.

Solid phase microextraction applied to the analysis of organophosphorus insecticides in fruits.

PubMed

Fytianos, K; Raikos, N; Theodoridis, G; Velinova, Z; Tsoukali, H

2006-12-01

Trace amounts of organophosphorus pesticides (OPs) were determined in various fruits by headspace solid phase microextraction (HS-SPME) and gas chromatography-nitrogen phosphorous detection (GC-NPD). Sampling from the headspace enhanced method selectivity, whereas at the same time improved fiber life time and method sensitivity. Diazinon, parathion, methyl parathion, malathion and fenithrothion were determined in various fruits: more than 150 samples of 21 types of fruits were studied. SPME-GC-NPD provided a useful and very efficient analytical tool: method linearity ranged from 1.2 to 700 ng/ml. Limits of detection (LODs) and quantitation (LOQs) ranged from 0.03 to 3 ng/ml and 0.12 to 10 ng/ml respectively, values well below the residue limits set by the EU. Less than 2% of the samples were found positive containing amounts higher than the EU limits. The effect of fruit peeling and washing was also investigated.

Portable Solid Phase Micro-Extraction Coupled with Ion Mobility Spectrometry System for On-Site Analysis of Chemical Warfare Agents and Simulants in Water Samples

PubMed Central

Yang, Liu; Han, Qiang; Cao, Shuya; Yang, Jie; Yang, Junchao; Ding, Mingyu

2014-01-01

On-site analysis is an efficient approach to facilitate analysis at the location of the system under investigation as it can result in more accurate, more precise and quickly available analytical data. In our work, a novel self-made thermal desorption based interface was fabricated to couple solid-phase microextraction with ion mobility spectrometry for on-site water analysis. The portable interface can be connected with the front-end of an ion mobility spectrometer directly without other modifications. The analytical performance was evaluated via the extraction of chemical warfare agents and simulants in water samples. Several parameters including ionic strength and extraction time have been investigated in detail. The application of the developed method afforded satisfactory recoveries ranging from 72.9% to 114.4% when applied to the analysis of real water samples. PMID:25384006

Determination of cocaine, benzoylecgonine and cocaethylene in human hair by solid-phase microextraction and gas chromatography-mass spectrometry.

PubMed

de Toledo, Fernanda Crossi Pereira; Yonamine, Mauricio; de Moraes Moreau, Regina Lucia; Silva, Ovandir Alves

2003-12-25

The present work describes a highly precise and sensitive method developed to detect cocaine (COC), benzoylecgonine (BE, its main metabolite) and cocaethylene (CE, transesterification product of the coingestion of COC with ethanol) in human head hair samples. The method was based on an alkylchloroformate derivatization of benzoylecgonine and the extraction of the analytes by solid-phase microextraction (SPME). Gas chromatography-mass spectrometry (GC-MS) was used to identify and quantify the analytes in selected ion monitoring mode (SIM). The limits of quantification and detection (LOQ and LOD) were: 0.1 ng/mg for COC and CE, and 0.5 ng/mg for BE. Good inter- and intra-assay precision was observed. The dynamic range of the assay was 0.1-50 ng/mg. The method is not time consuming and was shown to be easy to perform.

Role of solid-phase microextraction in the identification of highly volatile pheromones of two Rhinoceros beetles Scapanes australis and Strategus aloeus (Coleoptera, Scarabaeidae, Dynastinae).

PubMed

Rochat, D; Ramirez-Lucas, P; Malosse, C; Aldana, R; Kakul, T; Morin, J P

2000-07-14

Solid-phase microextraction (SPME) samplings from live insects or natural secretion allowed one to identify the aggregation pheromones of the pest beetles Scapanes australis and Strategus aloeus by efficient and rapid isolation of their highly volatile (72 < M(r) < 116) components. S. australis male pheromone was identified as a 84:12:4 (w/w) mixture of 2-butanol [67:33 (R)-(-):(S)-(+) ratio], 3-hydroxy-2-butanone and 2,3-butanediol [43:17:40 (R,R)-(-):(S,S)-(+):meso ratio], and S. aloeus pheromone as a 95.5:4.0:0.5 (w/w) mixture of 2-butanone, 3-pentanone and sec.-butyl acetate by GC-MS using conventional and chiral capillary columns. This is the first report of Scarabaeidae pheromones based on such small and common molecules.

Headspace solid-phase microextraction (HS-SPME) and liquid-liquid extraction (LLE): comparison of the performance in classification of ecstasy tablets. Part 2.

PubMed

Bonadio, Federica; Margot, Pierre; Delémont, Olivier; Esseiva, Pierre

2008-11-20

Headspace solid-phase microextraction (HS-SPME) is assessed as an alternative to liquid-liquid extraction (LLE) currently used for 3,4-methylenedioxymethampethamine (MDMA) profiling. Both methods were compared evaluating their performance in discriminating and classifying samples. For this purpose 62 different seizures were analysed using both extraction techniques followed by gas chromatography-mass spectroscopy (GC-MS). A previously validated method provided data for HS-SPME, whereas LLE data were collected applying a harmonized methodology developed and used in the European project CHAMP. After suitable pre-treatment, similarities between sample pairs were studied using the Pearson correlation. Both methods enable to distinguish between samples coming from the same pre-tabletting batches and samples coming from different pre-tabletting batches. This finding emphasizes the use of HS-SPME as an effective alternative to LLE, with additional advantages such as sample preparation and a solvent-free process.

Characterization of Aronia melanocarpa volatiles by headspace-solid-phase microextraction (HS-SPME), simultaneous distillation/extraction (SDE), and gas chromatography-olfactometry (GC-O) methods.

PubMed

Kraujalytė, Vilma; Leitner, Erich; Venskutonis, Petras Rimantas

2013-05-22

The profiles of volatile constituents of berry fruit of two Aronia melanocarpa genotypes were evaluated by headspace-solid-phase microextraction (HS-SPME), simultaneous distillation and extraction (SDE), and gas chromatography-olfactometry (GC-O). In total, 74 volatile compounds were identified in chokeberry juice, 3-penten-2-one, 3,9-epoxy-p-menth-1-ene, and benzaldehyde being the most abundant constituents; however, their percentage concentrations were remarkably different in the HS-SPME and SDE profiles. Twenty two aroma-active compounds were detected and characterized by the trained panelists in HS-SPME using GC-O detection frequency analysis. Olfactometry revealed that ethyl-2-methyl butanoate, ethyl-3-methyl butanoate, ethyl decanoate ("fruity" aroma notes), nonanal ("green" notes), unidentified compound possessing "moldy" odor, and some other volatiles may be very important constituents in formation of chokeberry aroma of both analyzed plant cultivars.

A green ultrasonic-assisted liquid-liquid microextraction based on deep eutectic solvent for the HPLC-UV determination of ferulic, caffeic and cinnamic acid from olive, almond, sesame and cinnamon oil.

PubMed

Khezeli, Tahere; Daneshfar, Ali; Sahraei, Reza

2016-04-01

A simple, inexpensive and sensitive ultrasonic-assisted liquid-liquid microextraction method based on deep eutectic solvent (UALLME-DES) was used for the extraction of three phenolic acids (ferulic, caffeic and cinnamic) from vegetable oils. In a typical experiment, deep eutectic solvent as green extraction solvent was added to n-hexane (as a typical oil medium) containing target analytes. Subsequently, the extraction was accelerated by sonication. After the extraction, phase separation (DES rich phase/n-hexane phase) was performed by centrifugation. DES rich phase (lower phase) was withdrawn by a micro-syringe and submitted to isocratic reverse-phase HPLC with UV detection. Under optimum conditions obtained by response surface methodology (RSM) and desirability function (DF), the method has good linear calibration ranges (between 1.30 and 1000 µg L(-1)), coefficients of determination (r(2)>0.9949) and low limits of detection (between 0.39 and 0.63 µg L(-1)). This procedure was successfully applied to the determination of target analytes in olive, almond, sesame and cinnamon oil samples. The relative mean recoveries ranged from 94.7% to 104.6%. Copyright © 2015 Elsevier B.V. All rights reserved.

Monitoring Pb in Aqueous Samples by Using Low Density Solvent on Air-Assisted Dispersive Liquid-Liquid Microextraction Coupled with UV-Vis Spectrophotometry.

PubMed

Nejad, Mina Ghasemi; Faraji, Hakim; Moghimi, Ali

2017-04-01

In this study, AA-DLLME combined with UV-Vis spectrophotometry was developed for pre-concentration, microextraction and determination of lead in aqueous samples. Optimization of the independent variables was carried out according to chemometric methods in three steps. According to the screening and optimization study, 86 μL of 1-undecanol (extracting solvent), 12 times syringe pumps, pH 2.0, 0.00% of salt and 0.1% DDTP (chelating agent) were chosen as the optimum independent variables for microextraction and determination of lead. Under the optimized conditions, R = 0.9994, and linearity range was 0.01-100 µg mL -1 . LOD and LOQ were 3.4 and 11.6 ng mL -1 , respectively. The method was applied for analysis of real water samples, such as tap, mineral, river and waste water.

Vortex-assisted liquid-liquid microextraction for the rapid screening of short-chain chlorinated paraffins in water.

PubMed

Chang, Chia-Yu; Chung, Wu-Hsun; Ding, Wang-Hsien

2016-01-01

The rapid screening of trace levels of short-chain chlorinated paraffins in various aqueous samples was performed by a simple and reliable procedure based on vortex-assisted liquid-liquid microextraction combined with gas chromatography and electron capture negative ionization mass spectrometry. The optimal vortex-assisted liquid-liquid microextraction conditions for 20 mL water sample were as follows: extractant 400 μL of dichloromethane; vortex extraction time of 1 min at 2500 × g; centrifugation of 3 min at 5000 × g; and no ionic strength adjustment. Under the optimum conditions, the limit of quantitation was 0.05 μg/L. Precision, as indicated by relative standard deviations, was less than 9% for both intra- and inter-day analysis. Accuracy, expressed as the mean extraction recovery, was above 91%. The vortex-assisted liquid-liquid microextraction with gas chromatography and electron capture negative ionization mass spectrometry method was successfully applied to quantitatively extract short-chain chlorinated paraffins from samples of river water and the effluent of a wastewater treatment plant, and the concentrations ranged from 0.8 to 1.6 μg/L. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of phenol compounds in surface water matrices by bar adsorptive microextraction-high performance liquid chromatography-diode array detection.

PubMed

Neng, Nuno R; Nogueira, José M F

2014-07-03

Bar adsorptive microextraction combined with liquid desorption followed by high performance liquid chromatography with diode array detection (BAµE-LD/HPLC-DAD) is proposed for the determination of trace levels of five phenol compounds (3-nitrophenol, 4-nitrophenol, bisphenol-A, 4-n-octylphenol and 4-n-nonylphenol) in surface water matrices. By using a polystyrene-divinylbenzene copolymer (PS-DVB) sorbent phase, high selectivity and efficiency is achieved even against polydimethylsiloxane through stir bar sorptive extraction. Assays performed by BAµE(PS-DVB)-LD/HPLC-DAD on 25 mL water samples spiked at the 10.0 µg/L levels yielded recoveries over 88.0%±5.7% for all five analytes, under optimized experimental conditions. The analytical performance showed good precision (RSD<15%), detection limits of 0.25 µg/L and linear dynamic ranges (1.0-25.0 μg/L) with determination coefficient higher than 0.9904. By using the standard addition method, the application of the present method to surface water matrices allowed very good performances at the trace level. The proposed methodology proved to be a suitable alternative to monitor phenol compounds in surface water matrices, showing to be easy to implement, reliable, sensitive and requiring a low sample volume.

Development of a fast and simple gas chromatographic protocol based on the combined use of alkyl chloroformate and solid phase microextraction for the assay of polyamines in human urine.

PubMed

Naccarato, Attilio; Elliani, Rosangela; Cavaliere, Brunella; Sindona, Giovanni; Tagarelli, Antonio

2018-05-11

Polyamines are aliphatic amines with low molecular weight that are widely recognized as one of the most important cancer biomarkers for early diagnosis and treatment. The goal of the work herein presented is the development of a rapid and simple method for the quantification of free polyamines (i.e., putrescine, cadaverine, spermidine, spermine) and N-monoacetylated polyamines (i.e., N 1 -Acetylspermidine, N 8 -Acetylspermidine, and N 1 -Acetylspermine) in human urine. A preliminary derivatization with propyl chloroformate combined with the use of solid phase microextraction (SPME) allowed for an easy and automatable protocol involving minimal sample handling and no consumption of organic solvents. The affinity of the analytes toward five commercial SPME coatings was evaluated in univariate mode, and the best result in terms of analyte extraction was achieved using the divinylbenzene/carboxen/polydimethylsiloxane fiber. The variables affecting the performance of SPME analysis were optimized by the multivariate approach of experimental design and, in particular, using a central composite design (CCD). The optimal working conditions in terms of response values are the following: extraction temperature 40 °C, extraction time of 15 min and no addition of NaCl. Analyses were carried out by gas chromatography-triple quadrupole mass spectrometry (GC-QqQ-MS) in selected reaction monitoring (SRM) acquisition mode. The developed method was validated according to the guidelines issued by the Food and Drug Administration (FDA). The satisfactory performances reached in terms of linearity, sensitivity (LOQs between 0.01 and 0.1 μg/mL), matrix effect (68-121%), accuracy, and precision (inter-day values between -24% and +16% and in the range 3.3-28.4%, respectively) make the proposed protocol suitable to be adopted for quantification of these important biomarkers in urine samples. Copyright © 2018 Elsevier B.V. All rights reserved.

Simultaneous determination of selegiline and desmethylselegiline in human body fluids by headspace solid-phase microextraction and gas chromatography-mass spectrometry.

PubMed

Kuriki, Ayako; Kumazawa, Takeshi; Lee, Xiao-Pen; Hasegawa, Chika; Kawamura, Mitsuru; Suzuki, Osamu; Sato, Keizo

2006-12-05

A method for the simultaneous determination of selegiline and its metabolite, desmethylselegiline, in human whole blood and urine is presented. The method, which combines a fiber-based headspace solid-phase microextraction (SPME) technique with gas chromatography-mass spectrometry (GC-MS), required optimization of various parameters (e.g., salt additives, extraction temperatures, extraction times and the extraction properties of the SPME fiber coatings). Pargyline was used as the internal standard. Extraction efficiencies for both selegiline and desmethylselegiline were 2.0-3.4% for whole blood, and 8.0-13.2% for urine. The regression equations for selegiline and desmethylselegiline extracted from whole blood were linear (r(2)=0.996 and 0.995) within the concentration ranges 0.1-10 and 0.2-20 ng/ml, respectively. For urine, the regression equations for selegiline and desmethylselegiline were linear (r(2)=0.999 and 0.998) within the concentration ranges 0.05-5.0 and 0.1-10 ng/ml, respectively. The limit of detection for selegiline and desmethylselegiline was 0.01-0.05 ng/ml for both samples. The lower and upper limits of quantification for each compound were 0.05-0.2 and 5-20 ng/ml, respectively. Intra- and inter-day coefficients of variation for selegiline and desmethylselegiline in both samples were not greater than 8.7 and 11.7%, respectively. The determination of selegiline and desmethylselegiline concentrations in Parkinson's disease patients undergoing continuous selegiline treatment is presented and is shown to validate the present methodology.

Polypyrrole/montmorillonite nanocomposite as a new solid phase microextraction fiber combined with gas chromatography-corona discharge ion mobility spectrometry for the simultaneous determination of diazinon and fenthion organophosphorus pesticides.

PubMed

Jafari, Mohammad T; Saraji, Mohammad; Sherafatmand, Hossein

2014-03-03

A novel solid phase microextraction (SPME) fiber was prepared and coupled with gas chromatography corona discharge ion mobility spectrometry (GC-CD-IMS) based on polypyrrole/montmorillonite nanocomposites for the simultaneous determination of diazinon and fenthion. The nanocomposite polymer was coated using a three-electrode electrochemical system and directly deposited on a Ni-Cr wire by applying a constant potential. The scanning electron microscopy images revealed that the new fiber exhibited a rather porous and homogenous surface. The thermal stability of the fabricated fiber was investigated by thermogravimetric analysis. The effects of different parameters influencing the extraction efficiency such as extraction temperature and time, salt addition, stirring rate, the amount of nanoclay, and desorption temperature were investigated and optimized. The method was exhaustively evaluated in terms of sensitivity, recovery, and reproducibility. The linearity ranges of 0.05-10 and 0.08-10 μg L(-1), and the detection limits of 0.020 and 0.035 μg L(-1) were obtained for diazinon and fenthion, respectively. The relative standard deviation values were calculated to be lower than 5% and 8% for intra-day and inter-day, respectively. Finally, the developed method was applied to determine the diazinon and fenthion (as model compounds) in cucumber, lettuce, apple, tap and river water samples. The satisfactory recoveries revealed the capability of the two-dimensional separation technique (retention time in GC and drift time in IMS) for the analysis of complex matrices extracted by SPME. Copyright © 2014 Elsevier B.V. All rights reserved.

Coupling of headspace solid phase microextraction with ultrasonic extraction for the determination of chlorinated pesticides in bird livers using gas chromatography.

PubMed

Lambropoulou, Dimitra A; Konstantinou, Ioannis K; Albanis, Triantafyllos A

2006-07-28

In the present study a combined analytical method involving ultrasonic extraction (USE), sulfuric acid clean-up and headspace solid-phase microextraction (HS-SPME) was developed for the determination of chlorinated pesticides (CPs) in bird livers. Extraction of CPs from 1g of liver was performed by ultrasonication for 30 min using 20 mL of solvent mixture (n-hexane:acetone (4:1, v/v)). The extract was subsequently subjected to a clean-up step for lipid removal. A comparative study on several clean-up procedures prior to the HS-SPME enrichment step was performed in order to achieve maximum recovery and optimal clean-up efficiency, which would provide suitable limits of detection in the gas chromatographic analysis. For this purpose, destructive (sulfuric acid or sodium hydroxide treatment) and non-destructive (alumina column) clean-up procedures has been assayed. The treatment of the extract with 40% (v/v) H2SO4 prior to HS-SPME process showed the best performance since lower detection limits and higher extraction efficiencies were obtained. The method detection limit ranged from 0.5 to 1.0 ng g(-1) wet weight and peak areas were proportional to analyte concentrations (r2>0.990) in the range of 5-500 ng g(-1) wet wt. The method was found to be reproducible (R.S.D.<10%) and effective under the operational conditions proposed and was applied successfully to the analysis of CPs in liver tissues of various bird species from Greece.

Novel synthesis of nanocomposite for the extraction of Sildenafil Citrate (Viagra) from water and urine samples: Process screening and optimization.

PubMed

Asfaram, Arash; Ghaedi, Mehrorang; Purkait, Mihir Kumar

2017-09-01

A sensitive analytical method is investigated to concentrate and determine trace level of Sildenafil Citrate (SLC) present in water and urine samples. The method is based on a sample treatment using dispersive solid-phase micro-extraction (DSPME) with laboratory-made Mn@ CuS/ZnS nanocomposite loaded on activated carbon (Mn@ CuS/ZnS-NCs-AC) as a sorbent for the target analyte. The efficiency was enhanced by ultrasound-assisted (UA) with dispersive nanocomposite solid-phase micro-extraction (UA-DNSPME). Four significant variables affecting SLC recovery like; pH, eluent volume, sonication time and adsorbent mass were selected by the Plackett-Burman design (PBD) experiments. These selected factors were optimized by the central composite design (CCD) to maximize extraction of SLC. The results exhibited that the optimum conditions for maximizing extraction of SLC were 6.0 pH, 300μL eluent (acetonitrile) volume, 10mg of adsorbent and 6min sonication time. Under optimized conditions, virtuous linearity of SLC was ranged from 30 to 4000ngmL -1 with R 2 of 0.99. The limit of detection (LOD) was 2.50ngmL -1 and the recoveries at two spiked levels were ranged from 97.37 to 103.21% with the relative standard deviation (RSD) less than 4.50% (n=15). The enhancement factor (EF) was 81.91. The results show that the combination UAE with DNSPME is a suitable method for the determination of SLC in water and urine samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Hydride generation coupled to microfunnel-assisted headspace liquid-phase microextraction for the determination of arsenic with UV-Vis spectrophotometry.

PubMed

Hashemniaye-Torshizi, Reihaneh; Ashraf, Narges; Arbab-Zavar, Mohammad Hossein

2014-12-01

In this research, a microfunnel-assisted headspace liquid-phase microextraction technique has been used in combination with hydride generation to determine arsenic (As) by UV-Vis spectrophotometry. The method is based on the reduction of As to arsine (AsH3) in acidic media by sodium tetrahydroborate (NaBH4) followed by its subsequent reaction with silver diethyldithiocarbamate (AgDDC) to give an absorbing complex at 510 nm. The complexing reagent (AgDDC) has been dissolved in a 1:1 (by the volume ratio) mixture of chloroform/chlorobenzene microdroplet and exposed to the generated gaseous arsine via a reversed microfunnel in the headspace of the sample solution. Several operating parameters affecting the performance of the method have been examined and optimized. Acetonitrile solvent has been added to the working samples as a sensitivity enhancement agent. Under the optimized operating conditions, the detection limit has been measured to be 0.2 ng mL(-1) (based on 3sb/m criterion, n b = 8), and the calibration curve was linear in the range of 0.5-12 ng mL(-1). The relative standard deviation for eight replicate measurements was 1.9 %. Also, the effects of several potential interferences have been studied. The accuracy of the method was validated through the analysis of JR-1 geological standard reference material. The method has been successfully applied for the determination of arsenic in raw and spiked soft drink and water samples with the recoveries that ranged from 91 to 106 %.

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.

Study of chemical stability of lemon oil components in sodium caseinate-lactose glycoconjugate-stabilized oil-in-water emulsions using solid-phase microextraction-gas chromatography.

PubMed

Sabik, Hassan; Achouri, Allaoua; Alfaro, Maria; Pelletier, Marylène; Belanger, Denis; Britten, Michel; Fustier, Patrick

2014-07-25

A headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC/MS) method was developed to quantify lemon oil components and their degradation products in oil-in-water (O/W) emulsions prepared with sodium caseinate-heated-lactose (NaC-T + Lact) glycoconjugates as wall materials at two pH values (3.0 and 6.8). NaC-T + Lact conjugates had a significantly lower solubility at both pHs. Hydrolysis prior to glycation enhanced the solubility of glycoconjugates. Glycation with lactose did not improve the emulsion activity of NaC, while caseinate glycoconjugates showed much stronger antioxidant activity than the NaC-control sample. This might be due to the presence of melanoidins formed between the sugar and amino acid compounds as supported by the increase in browning intensity. Among the SPME-fibres tested, carboxen/polydimethylsiloxane (CAR/PDMS) provided better results in terms of sensitivity and selectivity for oil lemon components and their degradation products. Storage studies of these emulsions demonstrated that glycated NaC-T + Lact showed protection against peroxidation compared to the control. However, acidic pH conditions altered their stability over storage time. The major off-flavor components (α-terpineol and carvone) were inhibited in emulsions stabilized with glycated NaC, particularly at pH 6.8. The use of NaC-T + Lact conjugates showed improved encapsulation efficiency and stability and could be used as potential food ingredient-emulsifiers for stabilising citrus oils against oxidative degradation in food and beverage applications.

Octadecyltrimethoxysilane functionalized ZnO nanorods as a novel coating for solid-phase microextraction with strong hydrophobic surface.

PubMed

Zeng, Jingbin; Liu, Haihong; Chen, Jinmei; Huang, Jianli; Yu, Jianfeng; Wang, Yiru; Chen, Xi

2012-09-21

In this paper, we have, for the first time, proposed an approach by combining self-assembled monolayers (SAMs) and nanomaterials (NMs) for the preparation of novel solid-phase microextraction (SPME) coatings. The self-assembly of octadecyltrimethoxysilane (OTMS) on the surface of ZnO nanorods (ZNRs) was selected as a model system to demonstrate the feasibility of this approach. The functionalization of OTMS on the surface of ZNRs was characterized and confirmed using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The OTMS-ZNRs coated fiber exhibited stronger hydrophobicity after functionalization, and its extraction efficiency for non-polar benzene homologues was increased by a factor of 1.5-3.6 when compared to a ZNRs fiber with almost identical thickness and façade. In contrast, the extraction efficiency of the OTMS-ZNRs coated fiber for polar aldehydes was 1.6-4.0-fold lower than that of the ZNRs coated fiber, further indicating its enhanced surface hydrophobicity. The OTMS-ZNRs coated fiber revealed a much higher capacity upon increasing the OTMS layer thickness to 5 μm, leading to a factor of 12.0-13.4 and 1.8-2.5 increase in extraction efficiency for the benzene homologues relative to a ZNRs coated fiber and a commercial PDMS fiber, respectively. The developed HS-SPME-GC method using the OTMS-ZNRs coated fiber was successfully applied to the determination of the benzene homologues in limnetic water samples with recovery ranging from 83 to 113% and relative standard deviations (RSDs) of less than 8%.

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.

Development of a new microextraction method based on elevated temperature dispersive liquid-liquid microextraction for determination of triazole pesticides residues in honey by gas chromatography-nitrogen phosphorus detection.

PubMed

Farajzadeh, Mir Ali; Mogaddam, Mohammad Reza Afshar; Ghorbanpour, Houshang

2014-06-20

In the present study, a rapid, highly efficient, and reliable sample preparation method named "elevated temperature dispersive liquid-liquid microextraction" followed by gas chromatography-nitrogen-phosphorus detection was developed for the extraction, preconcentration, and determination of five triazole pesticides (penconazole, hexaconazole, diniconazole, tebuconazole, and difenoconazole) in honey samples. In this method the temperature of high-volume aqueous phase was adjusted at an elevated temperature and then a disperser solvent containing an extraction solvent was rapidly injected into the aqueous phase. After cooling to room temperature, the phase separation was accelerated by centrifugation. Various parameters affecting the extraction efficiency such as type and volume of the extraction and disperser solvents, temperature, salt addition, and pH were evaluated. Under the optimum extraction conditions, the method resulted in low limits of detection and quantification within the range 0.05-0.21ngg(-1) in honey (15-70ngL(-1) in solution) and 0.15-1.1ngg(-1) in honey (45-210ngL(-1) in solution), respectively. Enrichment factors and extraction recoveries were in the ranges of 1943-1994 and 97-100%, respectively. The method precision was evaluated at 1.5ngg(-1) of each analyte, and the relative standard deviations were found to be less than 4% for intra-day (n=6) and less than 6% for inter-days. The method was successfully applied to the analysis of honey samples and difenoconazole was determined at ngg(-1) levels. Copyright © 2014 Elsevier B.V. All rights reserved.

Application of headspace solid-phase microextraction followed by gas chromatography coupled with mass spectrometry to determine esters of carboxylic acids and other volatile compounds in Dermestes maculatus and Dermestes ater lipids.

PubMed

Cerkowniak, Magdalena; Boguś, Mieczysława I; Włóka, Emilia; Stepnowski, Piotr; Gołębiowski, Marek

2018-02-01

A constant problem in veterinary medicine, human healthcare, agriculture, forestry and horticulture is the large number of pests, and the lack of effective methods to combat them which cause no harm to the rest of the environment. It is recommended and desired to reduce the use of chemicals and increase the use of agents based on knowledge acquired in the fields of biology, chemistry and agrochemicals. To learn the defense mechanisms of insects we should consider not only the site of their physiological ability to protect against external factors (cuticle), but also the possibility of chemical protection, formed by all compounds on the surface and in the body of insects. In this study, a procedure was developed to determine the esters of carboxylic acids in insect lipids. Headspace solid-phase microextraction was followed by gas chromatography coupled with gas spectrometry. First, the best conditions were selected for the analysis to obtain the best chromatographic separation. An RTx-5 column was used for this purpose. Polydimethylsiloxane/divinylbenzene (PDMS/DVB) and polyacrylate fibers were used to isolate acid esters. PDMS/DVB fiber achieved the best conditions for the extraction; the extraction time was 50 min, the extraction temperature was 105°C and the desorption time was 10 min at 230°C. These solid-phase microextraction conditions were used to analyze volatile compounds extracted from insects belonging to the Dermestidae family. Copyright © 2017 John Wiley & Sons, Ltd.

Variables controlling the recovery of ignitable liquid residues from simulated fire debris samples using solid-phase microextraction/gas chromatography

NASA Astrophysics Data System (ADS)

Furton, Kenneth G.; Almirall, Jose R.; Wang, Jing

1999-02-01

In this paper, we present data comparing a variety of different conditions for extracting ignitable liquid residues from simulated fire debris samples in order to optimize the conditions for using Solid Phase Microextraction. A simulated accelerant mixture containing 30 components, including those from light petroleum distillates, medium petroleum distillates and heavy petroleum distillates were used to study the important variables controlling Solid Phase Microextraction (SPME) recoveries. SPME is an inexpensive, rapid and sensitive method for the analysis of volatile residues from the headspace over solid debris samples in a container or directly from aqueous samples followed by GC. The relative effects of controllable variables, including fiber chemistry, adsorption and desorption temperature, extraction time, and desorption time, have been optimized. The addition of water and ethanol to simulated debris samples in a can was shown to increase the sensitivity when using headspace SPME extraction. The relative enhancement of sensitivity has been compared as a function of the hydrocarbon chain length, sample temperature, time, and added ethanol concentrations. The technique has also been optimized to the extraction of accelerants directly from water added to the fire debris samples. The optimum adsorption time for the low molecular weight components was found to be approximately 25 minutes. The high molecular weight components were found at a higher concentration the longer the fiber was exposed to the headspace (up to 1 hr). The higher molecular weight components were also found in higher concentrations in the headspace when water and/or ethanol was added to the debris.

A silica fiber coated with a ZnO-graphene oxide nanocomposite with high specific surface for use in solid phase microextraction of the antiepileptic drugs diazepam and oxazepam.

PubMed

Alizadeh, Reza; Salami, Maryam; Seidi, Shahram

2018-06-02

A novel ZnO-graphene oxide nanocomposite was prepared and is shown to be a viable coating on fused silica fibers for use in solid phase microextraction (SPME) of diazepam and oxazepam from urine, this followed by thermal desorption and gas chromatographic quantitation using a flame ionization detector. A central composite design was used to optimize extraction time, salt percentage, sample pH and desorption time. Limits of detection are 0.5 μg·L -1 for diazepam and 1.0 μg·L -1 for oxazepam. Repeatability and reproducibility for one fiber (n = 4), expressed as the relative standard deviation at a concentration of 50 μg·L -1 , are 8.3 and 11.3% for diazepam, and 6.7 and 10.1% for oxazepam. The fiber-to-fiber reproducibility is <17.6%. The calibration plots are linear in the 5.0-1000 μg·L -1 diazepam concentration range, and from 1.0-1000 μg·L -1 in case of oxazepam. The fiber for SPME has high chemical and thermal stability (even at 280 °C) after 50 extractions, and does not suffer from a reduction in the sorption capacity. Graphical abstract A hydrothermal method was introduced for preparation of ZnO- GO nano composite on a fused silica fiber as solid phase microextraction with high mechanical, chemical stability and long service life.

Optimization of multiwalled carbon nanotubes reinforced hollow-fiber solid-liquid-phase microextraction for the determination of polycyclic aromatic hydrocarbons in environmental water samples using experimental design.

PubMed

Hamedi, Raheleh; Hadjmohammadi, Mohammad Reza

2017-09-01

A novel design of hollow-fiber liquid-phase microextraction containing multiwalled carbon nanotubes as a solid sorbent, which is immobilized in the pore and lumen of hollow fiber by the sol-gel technique, was developed for the pre-concentration and determination of polycyclic aromatic hydrocarbons in environmental water samples. The proposed method utilized both solid- and liquid-phase microextraction media. Parameters that affect the extraction of polycyclic aromatic hydrocarbons were optimized in two successive steps as follows. Firstly, a methodology based on a quarter factorial design was used to choose the significant variables. Then, these significant factors were optimized utilizing central composite design. Under the optimized condition (extraction time = 25 min, amount of multiwalled carbon nanotubes = 78 mg, sample volume = 8 mL, and desorption time = 5 min), the calibration curves showed high linearity (R 2  = 0.99) in the range of 0.01-500 ng/mL and the limits of detection were in the range of 0.007-1.47 ng/mL. The obtained extraction recoveries for 10 ng/mL of polycyclic aromatic hydrocarbons standard solution were in the range of 85-92%. Replicating the experiment under these conditions five times gave relative standard deviations lower than 6%. Finally, the method was successfully applied for pre-concentration and determination of polycyclic aromatic hydrocarbons in environmental water samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dispersive liquid-liquid microextraction combined with microwave-assisted derivatization for determining lipoic acid and its metabolites in human urine.

PubMed

Tsai, Chia-Ju; Chen, Yen-Ling; Feng, Chia-Hsien

2013-10-04

This study explored dispersive liquid-liquid microextraction for extraction and concentration of lipoic acid in human urine. To improve the detection of lipoic acid by both capillary liquid chromatography (CapLC) with UV detection and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), microwave-assisted derivatization with 4-bromomethyl-6,7-dimethoxycoumarin was performed to render lipoic acid chromophores for UV detection and also high ionization efficiency in MALDI. All parameters that affected lipoic acid extraction and derivatization from urine were investigated and optimized. In the analyses of human urine samples, the two methods had a linear range of 0.1-20 μM with a correlation coefficient of 0.999. The detection limits of CapLC-UV and MALDI-TOF MS were 0.03 and 0.02 μM (S/N ≧ 3), respectively. The major metabolites of lipoic acid, including 6,8-bismethylthio-octanoic acid, 4,6-bismethylthio-hexanoic acid, and 2,4-bismethylthio-butanoic acid were also extracted by dispersive liquid-liquid microextraction and detected by MALDI-TOF MS. The minor metabolites (undetectable by MALDI-TOF MS), bisnorlipoic acid and tetranorlipoic acid were also extracted by dispersive liquid-liquid microextraction and identified with an LTQ Orbitrap mass spectrometer. After dispersive liquid-liquid microextraction and microwave-assisted derivatization, all lipoic acid derivatizations and metabolites were structurally confirmed by LTQ Orbitrap. Copyright © 2013 Elsevier B.V. All rights reserved.

Evaluating PCB Bioavailability Using Passive Samplers and Mussles at a Contaminated Sediment Site

EPA Science Inventory

Passive samplers, including semi-permeable membrane devices (SPMDs), solid phase microextraction (SPME) and polyethylene devices (PEDs), provide innovative tools for measuring hydrophobic organic contaminants (HOCs) originating from contaminated waters and sediments. Because the...

Aqueous two-phase based on ionic liquid liquid-liquid microextraction for simultaneous determination of five synthetic food colourants in different food samples by high-performance liquid chromatography.

PubMed

Sha, Ou; Zhu, Xiashi; Feng, Yanli; Ma, Weixing

2015-05-01

A rapid and effective method of aqueous two-phase systems based on ionic liquid microextraction for the simultaneous determination of five synthetic food colourants (tartrazine, sunset yellow, amaranth, ponceau 4R and brilliant blue) in food samples was established. High-performance liquid chromatography coupled with an ultraviolet detector of variable wavelength was used for the determinations. 1-alkyl-3-methylimidazolium bromide was selected as the extraction reagent. The extraction efficiency of the five colourants in the proposed system is influenced by the types of salts, concentrations of salt and [CnMIM]Br, as well as the extracting time. Under the optimal conditions, the extraction efficiencies for these five colourants were above 95%. The phase behaviours of aqueous two-phase system and extraction mechanism were investigated by UV-vis spectroscopy. This method was applied to the analysis of the five colourants in real food samples with the detection limit of 0.051-0.074 ng/mL. Good spiked recoveries from 93.2% to 98.9% were obtained. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ringer tablet-based ionic liquid phase microextraction: Application in extraction and preconcentration of neonicotinoid insecticides from fruit juice and vegetable samples.

PubMed

Farajzadeh, Mir Ali; Bamorowat, Mahdi; Mogaddam, Mohammad Reza Afshar

2016-11-01

An efficient, reliable, sensitive, rapid, and green analytical method for the extraction and determination of neonicotinoid insecticides in aqueous samples has been developed using ionic liquid phase microextraction coupled with high performance liquid chromatography-diode array detector. In this method, a few microliters of 1-hexyl-3-methylimidazolium hexafluorophosphate (as an extractant) is added onto a ringer tablet and it is transferred into a conical test tube containing aqueous phase of the analytes. By manually shaking, the ringer tablet is dissolved and the extractant is released into the aqueous phase as very tiny droplets to provide a cloudy solution. After centrifuging the extracted analytes into ionic liquid are collected at the bottom of a conical test tube. Under the optimum extraction conditions, the method showed low limits of detection and quantification between 0.12 and 0.33 and 0.41 and 1.11ngmL(-1), respectively. Extraction recoveries and enrichment factors were from 66% to 84% and 655% to 843%, respectively. Finally different aqueous samples were successfully analyzed using the proposed method. Copyright © 2016 Elsevier B.V. All rights reserved.

Solid-phase microextraction Ni-Ti fibers coated with functionalised silica particles immobilized in a sol-gel matrix.

PubMed

Azenha, Manuel; Ornelas, Mariana; Fernando Silva, A

2009-03-20

One of the possible approaches for the development of novel solid-phase microextraction (SPME) fibers is the physical deposition of porous materials onto a support using high-temperature epoxy glue. However, a major drawback arises from decomposition of epoxy glue at temperatures below 300 degrees C and instability in some organic solvents. This limitation motivated us to explore the possibility of replacing the epoxy glue with a sol-gel film, thermally more stable and resistant to organic solvents. We found that functionalised silica particles could be successfully attached to a robust Ni-Ti wire by using a UV-curable sol-gel film. The particles were found to be more important than the sol-gel layer during the microextraction process, as shown by competitive extraction trials and by the different extraction profiles observed with differently functionalised particles. If a quality control microscopic-check aiming at the rejection of fibers exhibiting unacceptably low particle load was conducted, acceptable (6-14%) reproducibility of preparation of C(18)-silica fibers was observed, and a strong indication of the durability of the fibers was also obtained. A cyclohexyldiol-silica fiber was used, as a simple example of applicability, for the successful determination of benzaldehyde, acetophenone and dimethylphenol at trace level in spiked tap water. Recoveries: 95-109%; limits of detection: 2-7 microg/L; no competition effects within the studied range (

Reversed-phase single drop microextraction followed by high-performance liquid chromatography with fluorescence detection for the quantification of synthetic phenolic antioxidants in edible oil samples.

PubMed

Farajmand, Bahman; Esteki, Mahnaz; Koohpour, Elham; Salmani, Vahid

2017-04-01

The reversed-phase mode of single drop microextraction has been used as a preparation method for the extraction of some phenolic antioxidants from edible oil samples. Butylated hydroxyl anisole, tert-butylhydroquinone and butylated hydroxytoluene were employed as target compounds for this study. High-performance liquid chromatography followed by fluorescence detection was applied for final determination of target compounds. The most interesting feature of this study is the application of a disposable insulin syringe with some modification for microextraction procedure that efficiently improved the volume and stability of the solvent microdrop. Different parameters such as the type and volume of solvent, sample stirring rate, extraction temperature, and time were investigated and optimized. Analytical performances of the method were evaluated under optimized conditions. Under the optimal conditions, relative standard deviations were between 4.4 and 10.2%. Linear dynamic ranges were 20-10 000 to 2-1000 μg/g (depending on the analytes). Detection limits were 5-670 ng/g. Finally, the proposed method was successfully used for quantification of the antioxidants in some edible oil samples prepared from market. Relative recoveries were achieved from 88 to 111%. The proposed method had a simplicity of operation, low cost, and successful application for real samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Application of a surfactant-assisted dispersive liquid-liquid microextraction method along with central composite design for micro-volume based spectrophotometric determination of low level of Cr(VI) ions in aquatic samples.

PubMed

Sobhi, Hamid Reza; Azadikhah, Efat; Behbahani, Mohammad; Esrafili, Ali; Ghambarian, Mahnaz

2018-05-09

A fast, simple, low cost surfactant-assisted dispersive liquid-liquid microextraction method along with central composite design for the determination of low level of Cr(VI) ions in several aquatic samples has been developed. Initially, Cr(VI) ions present in the aqueous sample were readily reacted with 1,5‑diphenylcarbazide (DPC) in acidic medium through complexation. Sodium dodecyl sulfate (SDS), as an anionic surfactant, was then employed as an ion-pair agent to convert the cationic complex into the neutral one. Following on, the whole aqueous phase underwent a dispersive liquid-liquid microextraction (DLLME) leading to the transfer of the neutral complex into the fine droplet of organic extraction phase. A micro-volume spectrophotometer was used to determine Cr(VI) concentrations. Under the optimized conditions predicted by the statistical design, the limit of quantification (LOQ) obtained was reported to be 5.0 μg/L, and the calibration curve was linear over the concentration range of 5-100 μg/L. Finally, the method was successfully implemented for the determination of low levels of Cr(VI) ions in various real aquatic samples and the accuracies fell within the range of 83-102%, while the precision varied in the span of 1.7-5.2%. Copyright © 2018. Published by Elsevier B.V.

Solid phase microextraction of macrolide, trimethoprim, and sulfonamide antibiotics in wastewaters.

PubMed

McClure, Evelyn L; Wong, Charles S

2007-10-26

In this work, we optimize a solid phase microextraction (SPME) method for the simultaneous collection of antibiotics (sulfonamides, macrolides, and trimethoprim) present in wastewaters. The performance of the SPME method is compared to a solid phase extraction (SPE) method. Analytes in both cases were quantified by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) with electrospray ionization. The advantages offered by SPME in this application are: decreased sample volume requirements, ease of sample processing and extraction, decreased cost, and most importantly, elimination of electrospray matrix effects. Despite having higher limits of quantification (16-1380 ng/L in influent and 35-260 ng/L in effluent), nearly all of the compounds found to be present in Edmonton Gold Bar wastewater by SPE were measurable by SPME (i.e., sulfamethoxazole, trimethoprim, erythromycin, and clarithromycin), with values similar to those obtained using the former method. Limits of quantification for the SPE method for the measured compounds were 4.7-15 ng/L and 0.86-6.1 ng/L for influent and effluent, respectively.

Simple determination of fluoride in biological samples by headspace solid-phase microextraction and gas chromatography-tandem mass spectrometry.

PubMed

Kwon, Sun-Myung; Shin, Ho-Sang

2015-08-14

A simple and convenient method to detect fluoride in biological samples was developed. This method was based on derivatization with 2-(bromomethyl)naphthalene, headspace solid phase microextraction (HS-SPME) in a vial, and gas chromatography-tandem mass spectrometric detection. The HS-SPME parameters were optimized as follows: selection of CAR/PDMS fiber, 0.5% 2-(bromomethyl)naphthalene, 250 mg/L 15-crown-5-ether as a phase transfer catalyst, extraction and derivatization temperature of 95 °C, heating time of 20 min and pH of 7.0. Under the established conditions, the lowest limits of detection were 9 and 11 μg/L in 1.0 ml of plasma and urine, respectively, and the intra- and inter-day relative standard deviation was less than 7.7% at concentrations of 0.1 and 1.0 mg/L. The calibration curve showed good linearity of plasma and urine with r=0.9990 and r=0.9992, respectively. This method is simple, amenable to automation and environmentally friendly. Copyright © 2015 Elsevier B.V. All rights reserved.

Volatile compounds of dry beans (Phaseolus vulgaris L.).

PubMed

Oomah, B Dave; Liang, Lisa S Y; Balasubramanian, Parthiba

2007-12-01

Volatile compounds of uncooked dry bean (Phaseolus vulgaris L.) cultivars representing three market classes (black, dark red kidney and pinto) grown in 2005 were isolated with headspace solid phase microextraction (HS-SPME), and analyzed with gas chromatography mass spectrometry (GC-MS). A total of 62 volatiles consisting of aromatic hydrocarbons, aldehydes, alkanes, alcohols and ketones represented on average 62, 38, 21, 12, and 9 x 10(6) total area counts, respectively. Bean cultivars differed in abundance and profile of volatiles. The combination of 18 compounds comprising a common profile explained 79% of the variance among cultivars based on principal component analysis (PCA). The SPME technique proved to be a rapid and effective method for routine evaluation of dry bean volatile profile.

Ionic liquid foam floatation coupled with ionic liquid dispersive liquid-liquid microextraction for the separation and determination of estrogens in water samples by high-performance liquid chromatography with fluorescence detection.

PubMed

Zhang, Rui; Wang, Chuanliu; Yue, Qiaohong; Zhou, Tiecheng; Li, Na; Zhang, Hanqi; Hao, Xiaoke

2014-11-01

An ionic liquid foam floatation coupled with ionic liquid dispersive liquid-liquid microextraction method was proposed for the extraction and concentration of 17-α-estradiol, 17-β-estradiol-benzoate, and quinestrol in environmental water samples by high-performance liquid chromatography with fluorescence detection. 1-Hexyl-3-methylimidazolium tetrafluoroborate was applied as foaming agent in the foam flotation process and dispersive solvent in microextraction. The introduction of the ion-pairing and salting-out agent NH4 PF6 was beneficial to the improvement of recoveries for the hydrophobic ionic liquid phase and analytes. Parameters of the proposed method including concentration of 1-hexyl-3-methylimidazolium tetrafluoroborate, flow rate of carrier gas, floatation time, types and concentration of ionic liquids, salt concentration in samples, extraction time, and centrifugation time were evaluated. The recoveries were between 98 and 105% with relative standard deviations lower than 7% for lake water and well water samples. The isolation of the target compounds from the water was found to be efficient, and the enrichment factors ranged from 4445 to 4632. This developing method is free of volatile organic solvents compared with regular extraction. Based on the unique properties of ionic liquids, the application of foam floatation, and dispersive liquid-liquid microextraction was widened. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nanocoating cellulose paper based microextraction combined with nanospray mass spectrometry for rapid and facile quantitation of ribonucleosides in human urine.

PubMed

Wan, Lingzhong; Zhu, Haijing; Guan, Yafeng; Huang, Guangming

2017-07-01

A rapid and facile analytical method for quantification of ribonucleosides in human urine was developed by the combination of nanocoating cellulose paper based microextraction and nanoelectrospray ionization-tandem mass spectrometry (nESI-MS/MS). Cellulose paper used for microextraction was modified by nano-precision deposition of uniform ultrathin zirconia gel film using a sol-gel process. Due to the large surface area of the cellulose paper and the strong affinity between zirconia and the cis-diol compounds, the target analytes were selectively extracted from the complex matrix. Thus, the detection sensitivity was greatly improved. Typically, the nanocoating cellulose paper was immersed into the diluted urine for selective extraction of target analytes, then the extracted analytes were subjected to nESI-MS/MS detection. The whole analytical procedure could be completed within 10min. The method was evaluated by the determination of ribonucleosides (adenosine, cytidine, uridine, guanosine) in urine sample. The signal intensities of the ribonuclesides extracted by the nanocoating cellulose paper were greatly enhanced by 136-459-folds compared with the one of the unmodified cellulose paper based microextraction. The limits of detection (LODs) and the limits of quantification (LOQs) of the four ribonucleosides were in the range of 0.0136-1.258μgL -1 and 0.0454-4.194μgL -1 , respectively. The recoveries of the target nucleosides from spiked human urine were in the range of 75.64-103.49% with the relative standard deviations (RSDs) less than 9.36%. The results demonstrate the potential of the proposed method for rapid and facile determination of endogenous ribonucleosides in urine sample. Copyright © 2017. Published by Elsevier B.V.

Optimization and determination of Cd (II) in different environmental water samples with dispersive liquid-liquid microextraction preconcentration combined with inductively coupled plasma optical emission spectrometry.

PubMed

Salahinejad, Maryam; Aflaki, Fereydoon

2011-06-01

Dispersive liquid-liquid microextraction followed by inductively coupled plasma-optical emission spectrometry has been investigated for determination of Cd(II) ions in water samples. Ammonium pyrrolidine dithiocarbamate was used as chelating agent. Several factors influencing the microextraction efficiency of Cd (II) ions such as extracting and dispersing solvent type and their volumes, pH, sample volume, and salting effect were optimized. The optimization was performed both via one variable at a time, and central composite design methods and the optimum conditions were selected. Both optimization methods showed nearly the same results: sample size 5 mL; dispersive solvent ethanol; dispersive solvent volume 2 mL; extracting solvent chloroform; extracting solvent volume 200 [Formula: see text]L; pH and salt amount do not affect significantly the microextraction efficiency. The limits of detection and quantification were 0.8 and 2.5 ng L( - 1), respectively. The relative standard deviation for five replicate measurements of 0.50 mg L( - 1) of Cd (II) was 4.4%. The recoveries for the spiked real samples from tap, mineral, river, dam, and sea waters samples ranged from 92.2% to 104.5%.

On-line packed magnetic in-tube solid phase microextraction of acidic drugs such as naproxen and indomethacin by using Fe3O4@SiO2@layered double hydroxide nanoparticles with high anion exchange capacity.

PubMed

Shamsayei, Maryam; Yamini, Yadollah; Asiabi, Hamid; Safari, Meysam

2018-02-22

The authors describe a 3-component nanoparticle system composed of a silica-coated magnetite (Fe 3 O 4 ) core and a layered double (Cu-Cr) hydroxide nanoplatelet shell. The sorbent has a high anion exchange capacity for extraction anionic species. A simple online system, referred to as "on-line packed magnetic-in-tube solid phase microextraction" was designed. The nanoparticles were placed in a stainless steel cartridge via dry packing. The cartridge was then applied to the preconcentration acidic drugs including naproxen and indomethacin from urine and plasma. Extraction and desorption times, pH values of the sample solution and flow rates of sample solution and eluent were optimized. Analytes were then quantified by HPLC with UV detection. Under optimal conditions, the limits of detection range from 70 to 800 ng L -1 , with linear responses from 0.1-500 μg L -1 (water samples), 0.6-500 μg L -1 (spiked urine), and 0.9-500 μg L -1 (spiked plasma). The inter- and intra-assay precisions (RSDs, for n = 5) are in the range of 2.2-5.4%, 2.8-4.9%, and 2.0-5.2% at concentration levels of 5, 25 and 50 μg L -1 , respectively. The method was applied to the analysis of the drugs in spiked human urine and plasma, and good results were achieved. Graphical abstract Fe 3 O 4 @SiO 2 @CuCr-LDH magnetic nanoparticles were synthesized and packed in to a stainless steel column. The column was applied to solid phase microextraction of acidic drugs from biological samples.

Development of a multi-preservative method based on solid-phase microextraction-gas chromatography-tandem mass spectrometry for cosmetic analysis.

PubMed

Alvarez-Rivera, Gerardo; Vila, Marlene; Lores, Marta; Garcia-Jares, Carmen; Llompart, Maria

2014-04-25

A simple methodology based on solid-phase microextraction (SPME) followed by gas chromatography-tandem mass spectrometry (GC-MS/MS) has been developed for the simultaneous analysis of different classes of preservatives including benzoates, bronidox, 2-phenoxyethanol, parabens, BHA, BHT and triclosan in cosmetic products. In situ acetylation and subsequent organic modifier addition have been successfully implemented in the SPME process as an effective extractive strategy for matrix effect compensation and chromatographic performance improvement. Main factors affecting SPME procedure such as fiber coating, sampling mode, extraction temperature and salt addition (NaCl) were evaluated by means of a 3×2(3-1) factorial experimental design. The optimal experimental conditions were established as follows: direct solid-phase microextraction (SPME) at 40°C and addition of NaCl (20%, w/v), using a DVB/CAR/PDMS fiber coating. Due to the complexity of the studied matrices, method performance was evaluated in a representative variety of both rinse-off and leave-on samples, demonstrating to have a broad linear range (R(2)>0.9964). In general, quantitative recoveries (>85% in most cases) and satisfactory precision (RSD<13% for most of compounds) were obtained, with limits of detection (LODs) well below the maximum authorized concentrations established by the European legislation. One of the most important achievements of this work was the use of external calibration with cosmetic-matched standards to accurately quantify the target analytes. The validated methodology was successfully applied to the analysis of different types of cosmetic formulations including body milks, moisturizing creams, deodorants, sunscreen, bath gel, dental cream and make-up products amongst others, demonstrating to be a reliable multi-preservative methododology for routine control. Copyright © 2014 Elsevier B.V. All rights reserved.

Optimization of total vaporization solid-phase microextraction (TV-SPME) for the determination of lipid profiles of Phormia regina, a forensically important blow fly species.

PubMed

Kranz, William; Carroll, Clinton; Dixon, Darren; Picard, Christine; Goodpaster, John

2017-11-01

A new method has been developed for the determination of fatty acids, sterols, and other lipids which naturally occur within pupae of the blow fly Phormia regina. The method relies upon liquid extraction in non-polar solvent, followed by derivatization using N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) w/ 1% trimethylchlorsilane (TMCS) carried out inside the sample vial. The analysis is facilitated by total vaporization solid-phase microextraction (TV-SPME), with gas chromatography-mass spectrometry (GC-MS) serving as the instrumentation for analysis. The TV-SPME delivery technique is approximately a factor of five more sensitive than traditional liquid injection, which may alleviate the need for rotary evaporation, reconstitution, collection of high performance liquid chromatography fractions, and many of the other pre-concentration steps that are commonplace in the current literature. Furthermore, the ability to derivatize the liquid extract in a single easy step while increasing sensitivity represents an improvement over current derivatization methods. The most common lipids identified in fly pupae were various saturated and unsaturated fatty acids ranging from lauric acid (12:0) to arachinoic acid (20:4), as well as cholesterol. The concentrations of myristic acid (14:0), palmitelaidic acid (16:2), and palmitoleic acid (16:1) were the most reliable indicators of the age of the pupae. Graphical abstract Blow fly pupae were extracted prior to emerging as adults. The extracts were analyzed via total vaporization solid-phase microextraction (TV-SPME), revealing a complex mixture of lipids that could be associated with the age of the insect. This information may assist in determining a post-mortum interval (PMI) in a death investigation.

Ultrasensitive Speciation Analysis of Mercury in Rice by Headspace Solid Phase Microextraction Using Porous Carbons and Gas Chromatography-Dielectric Barrier Discharge Optical Emission Spectrometry.

PubMed

Lin, Yao; Yang, Yuan; Li, Yuxuan; Yang, Lu; Hou, Xiandeng; Feng, Xinbin; Zheng, Chengbin

2016-03-01

Rice consumption is a primary pathway for human methylmercury (MeHg) exposure in inland mercury mining areas of Asia. In addition, the use of iodomethane, a common fumigant that significantly accelerates the methylation of mercury in soil under sunlight, could increase the MeHg exposure from rice. Conventional hyphenated techniques used for mercury speciation analysis are usually too costly for most developing countries. Consequently, there is an increased interest in the development of sensitive and inexpensive methods for the speciation of mercury in rice. In this work, gas chromatography (GC) coupled to dielectric barrier discharge optical emission spectrometry (DBD-OES) was developed for the speciation analysis of mercury in rice. Prior to GC-DBD-OES analysis, mercury species were derivatized to their volatile species with NaBPh4 and preconcentrated by headspace solid phase microextraction using porous carbons. Limits of detection of 0.5 μg kg(-1) (0.16 ng), 0.75 μg kg(-1) (0.24 ng), and 1.0 μg kg(-1) (0.34 ng) were obtained for Hg(2+), CH3Hg(+), and CH3CH2Hg(+), respectively, with relative standard deviations (RSDs) better than 5.2% and 6.8% for one fiber or fiber-to-fiber mode, respectively. Recoveries of 90-105% were obtained for the rice samples, demonstrating the applicability of the proposed technique. Owing to the small size, low power, and low gas consumption of DBD-OES as well as efficient extraction of mercury species by porous carbons headspace solid phase micro-extraction, the proposed technique provides several advantages including compactness, cost-effectiveness, and potential to couple with miniature GC to accomplish the field speciation of mercury in rice compared to conventional hyphenated techniques.

Preparation of poly(trimethyl-2-methacroyloxyethylammonium chloride-co-ethylene glycol dimethacrylate) monolith and its application in solid phase microextraction of brominated flame retardants.

PubMed

Yang, Ting-ting; Zhou, Lin-feng; Qiao, Jun-qin; Lian, Hong-zhen; Ge, Xin; Chen, Hong-yuan

2013-05-24

A capillary poly(trimethyl-2-methacroyloxyethylammonium chloride-co-ethylene glycol dimethacrylate) monolith was in situ synthesized by thermally initiated free radical co-polymerization using trimethyl-2-methacroyloxyethylammonium chloride (MATE) and ethylene glycol dimethacrylate (EGDMA) as functional monomer and cross-linker, respectively. N,N-dimethylformamide and polyethylene glycol 6000 were used as solvent and porogen, respectively. The morphology and porous structure of the resulting monoliths were assessed by scanning electron microscope. In order to prepare practically useful poly(MATE-co-EGDMA) monoliths with low flow resistance and good mechanical strength, some parameters such as PEG-6000 to DMF ratio, total monomer to porogen ratio, and crosslinker to monomer ratio were optimized systematically. Moreover, the extraction mechanism was evaluated using two series of compounds, alkylbenzenes and weak acids, as model compounds on poly(MATE-co-EGDMA) monoliths as liquid chromatographic stationary phase. Finally, the monoliths were applied as the solid phase microextraction medium, and a simple off-line method for simultaneous determination of three brominated flame retardants, 2,4,6-tribromophenol (TBP), tetrabromobisphenol A (TBBPA) and 4,4'-dibrominated diphenyl ether (DBDPE), in environmental waters was developed by coupling the polymer monolith microextraction to HPLC with UV detection. The regression equations for these three brominated flame retardants showed good linearity from their limit of quantification to 5000ng/mL. The limits of detection were 0.20, 0.15 and 0.10ng/mL for TBP, TBBPA and DBDPE, respectively. The recovery of the proposed method was 78.7-106.1% with intra-day relative standard deviation of 1.3-4.4%. Copyright © 2013 Elsevier B.V. All rights reserved.

Solid-phase microextraction with temperature-programmed desorption for the analysis of iodination disinfection byproducts.

PubMed

Frazey, P A; Barkley, R M; Sievers, R E

1998-02-01

An analytical approach for the determination of chlorination and iodination disinfection byproducts based on solid-phase microextraction (SPME) was developed. Solid-phase microextraction presents a simple, rapid, sensitive, and solvent-free approach to sample preparation in which analytes in either air or water matrixes are extracted into the polymeric coating of an optical fiber. Analytes are subsequently thermally desorbed in the injection port of a gas chromatograph for separation, detection, and quantitation. Thermal degradation of iodoform was observed during desorption from a polyacrylate fiber in initial GC/MS and GC/ECD experiments. Experiments were designed to determine SPME conditions that would allow quantification without significant degradation of analytes. Isothermal and temperature-programmed thermal desorptions were evaluated for efficacy in transferring analytes with wide-ranging volatilities and thermal stabilities into chromatographic analysis columns. A temperature-programmed desorption (TPD) (120-200 degrees C at 5 degrees C/min with an on-column injection port or 150-200 degrees C at 25 degrees C/min with a split/splitless injection port) was able to efficiently remove analytes with wide-ranging volatilities without causing thermal degradation. The SPME-TPD method was linear over 2-3 orders of magnitude with an electron capture detector and detection limits were in the submicrogram per liter range. Precision and detection limits for selected trihalomethanes were comparable to those of EPA method 551. Extraction efficiencies were not affected by the presence of 10 mg/L soap, 15 mg/L sodium iodide, and 6000 mg/L sodium thiosulfate. The SPME-TPD technique was applied to the determination of iodination disinfection byproducts from individual precursor compounds using GC/MS and to the quantitation of iodoform at trace levels in a water recycle system using GC/ECD.

A simple and sensitive vortex-assisted ionic liquid-dispersive microextraction and spectrophotometric determination of selenium in food samples.

PubMed

Bağda, Esra; Tüzen, Mustafa

2017-10-01

In the present study, a novel and eco-friendly vortex-assisted ionic liquid-based microextraction method was developed for the determination of selenium in food. The microextraction method is based on the liberation of iodine in the presence of selenium; the liberated iodine reacts with I - to form I 3 - . Anionic I 3 - reacts with cationic crystal violet dye, and the product is extracted into 1-hexyl-3-methylimidazolium hexafluorophosphate phase in the presence of Triton X-114. The proposed method is linear in the range of 2.0-70µgL -1 and has a detection limit of 9.8×10 -2 µgL -1 . Relative standard deviations were 3.67% and 2.89% for the five replicate measurements of 14 and 35µgL -1 Se(IV), respectively. The proposed method was successfully applied to different food samples (NIST SRM 2976 mussel tissue, pepper, ginger, wheat flour, red lentil, traditional soup, cornflour, cornstarch, and garlic) after microwave digestion. Copyright © 2017 Elsevier Ltd. All rights reserved.

A new open tubular capillary microextraction and sweeping for the analysis of super low concentration of hydrophobic compounds.

PubMed

Xia, Zhining; Gan, Tingting; Chen, Hua; Lv, Rui; Wei, Weili; Yang, Fengqing

2010-10-01

A sample pre-concentration method based on the in-line coupling of in-tube solid-phase microextraction and electrophoretic sweeping was developed for the analysis of hydrophobic compounds. The sample pre-concentration and electrophoretic separation processes were simply and sequentially carried out with a (35%-phenyl)-methylpolysiloxane-coated capillary. The developed method was validated and applied to enrich and separate several pharmaceuticals including loratadine, indomethacin, ibuprofen and doxazosin. Several parameters of microextration were investigated such as temperature, pH and eluant. And the concentration of microemulsion that influences separation efficiency and microextraction efficiency were also studied. Central composite design was applied for the optimization of sampling flow rate and sampling time that interact in a very complex way with each other. The precision, sensitivity and recovery of the method were investigated. Under the optimal conditions, the maximum enrichment factors for loratadine, indomethacin, ibuprofen and doxazosin in aqueous solutions are 1355, 571, 523 and 318, respectively. In addition, the developed method was applied to determine loratadine in rabbit blood sample.

Development of garlic bioactive compounds analytical methodology based on liquid phase microextraction using response surface design. Implications for dual analysis: Cooked and biological fluids samples.

PubMed

Ramirez, Daniela Andrea; Locatelli, Daniela Ana; Torres-Palazzolo, Carolina Andrea; Altamirano, Jorgelina Cecilia; Camargo, Alejandra Beatriz

2017-01-15

Organosulphur compounds (OSCs) present in garlic (Allium sativum L.) are responsible of several biological properties. Functional foods researches indicate the importance of quantifying these compounds in food matrices and biological fluids. For this purpose, this paper introduces a novel methodology based on dispersive liquid-liquid microextraction (DLLME) coupled to high performance liquid chromatography with ultraviolet detector (HPLC-UV) for the extraction and determination of organosulphur compounds in different matrices. The target analytes were allicin, (E)- and (Z)-ajoene, 2-vinyl-4H-1,2-dithiin (2-VD), diallyl sulphide (DAS) and diallyl disulphide (DADS). The microextraction technique was optimized using an experimental design, and the analytical performance was evaluated under optimum conditions. The desirability function presented an optimal value for 600μL of chloroform as extraction solvent using acetonitrile as dispersant. The method proved to be reliable, precise and accurate. It was successfully applied to determine OSCs in cooked garlic samples as well as blood plasma and digestive fluids. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fully-automated in-syringe dispersive liquid-liquid microextraction for the determination of caffeine in coffee beverages.

PubMed

Frizzarin, Rejane M; Maya, Fernando; Estela, José M; Cerdà, Víctor

2016-12-01

A novel fully-automated magnetic stirring-assisted lab-in-syringe analytical procedure has been developed for the fast and efficient dispersive liquid-liquid microextraction (DLLME) of caffeine in coffee beverages. The procedure is based on the microextraction of caffeine with a minute amount of dichloromethane, isolating caffeine from the sample matrix with no further sample pretreatment. Selection of the relevant extraction parameters such as the dispersive solvent, proportion of aqueous/organic phase, pH and flow rates have been carefully evaluated. Caffeine quantification was linear from 2 to 75mgL(-1), with detection and quantification limits of 0.46mgL(-1) and 1.54mgL(-1), respectively. A coefficient of variation (n=8; 5mgL(-1)) of a 2.1% and a sampling rate of 16h(-1), were obtained. The procedure was satisfactorily applied to the determination of caffeine in brewed, instant and decaf coffee samples, being the results for the sample analysis validated using high-performance liquid chromatography. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sol-gel niobia sorbent with a positively charged octadecyl ligand providing enhanced enrichment of nucleotides and organophosphorus pesticides in capillary microextraction for online HPLC analysis.

PubMed

Kesani, Sheshanka; Malik, Abdul

2018-04-01

A niobia-based sol-gel organic-inorganic hybrid sorbent carrying a positively charged C 18 ligand (Nb 2 O 5 -C 18 (+ve)) was synthesized to achieve enhanced enrichment capability in capillary microextraction of organophosphorus compounds (which include organophosphorus pesticides and nucleotides) before their online analysis by high-performance liquid chromatography. The sorbent was designed to simultaneously provide three different types of molecular level interactions: electrostatic, Lewis acid-base, and van der Waals interactions. To understand relative contributions of various molecular level analyte-sorbent interactions in the extraction process, two other sol-gel niobia sorbents were also created: (a) a purely inorganic sol-gel niobia sorbent (Nb 2 O 5 ) and (b) an organic-inorganic hybrid sol-gel niobia sorbent carrying an electrically neutral-bonded octadecyl ligand (Nb 2 O 5 -C 18 ). The extraction efficiency of the created sol-gel niobia sorbent (Nb 2 O 5 -C 18 (+ve)) was compared with that of analogously designed and synthesized titania-based sol-gel sorbent (TiO 2 -C 18 (+ve)), taking into consideration that titania-based sorbents present state-of-the-art extraction media for organophosphorus compounds. In capillary microextraction with high-performance liquid chromatography analysis, Nb 2 O 5 -C 18 (+ve) had shown 40-50% higher specific extraction values (a measure of extraction efficiency) over that of TiO 2 -C 18 (+ve). Compared to TiO 2 -C 18 (+ve), Nb 2 O 5 -C 18 (+ve) also provided superior analyte desorption efficiency (96 vs. 90%) during the online release of the extracted organophosphorus pesticides from the sorbent coating in the capillary microextraction capillary to the chromatographic column using reversed-phase high-performance liquid chromatography mobile phase. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Introducing a new and rapid microextraction approach based on magnetic ionic liquids: Stir bar dispersive liquid microextraction.

PubMed

Chisvert, Alberto; Benedé, Juan L; Anderson, Jared L; Pierson, Stephen A; Salvador, Amparo

2017-08-29

With the aim of contributing to the development and improvement of microextraction techniques, a novel approach combining the principles and advantages of stir bar sorptive extraction (SBSE) and dispersive liquid-liquid microextraction (DLLME) is presented. This new approach, termed stir bar dispersive liquid microextraction (SBDLME), involves the addition of a magnetic ionic liquid (MIL) and a neodymium-core magnetic stir bar into the sample allowing the MIL coat the stir bar due to physical forces (i.e., magnetism). As long as the stirring rate is maintained at low speed, the MIL resists rotational (centrifugal) forces and remains on the stir bar surface in a manner closely resembling SBSE. By increasing the stirring rate, the rotational forces surpass the magnetic field and the MIL disperses into the sample solution in a similar manner to DLLME. After extraction, the stirring is stopped and the MIL returns to the stir bar without the requirement of an additional external magnetic field. The MIL-coated stir bar containing the preconcentrated analytes is thermally desorbed directly into a gas chromatographic system coupled to a mass spectrometric detector (TD-GC-MS). This novel approach opens new insights into the microextraction field, by using the benefits provided by SBSE and DLLME simultaneously, such as automated thermal desorption and high surface contact area, respectively, but most importantly, it enables the use of tailor-made solvents (i.e., MILs). To prove its utility, SBDLME has been used in the extraction of lipophilic organic UV filters from environmental water samples as model analytical application with excellent analytical features in terms of linearity, enrichment factors (67-791), limits of detection (low ng L -1 ), intra- and inter-day repeatability (RSD<15%) and relative recoveries (87-113%, 91-117% and 89-115% for river, sea and swimming pool water samples, respectively). Copyright © 2017 Elsevier B.V. All rights reserved.

Comparing the Accumulation of PCBs by Passive Samplers and Mussels from the Water Column at a Contaminated Sediment Site

EPA Science Inventory

Passive samplers, including semi-permeable membrane devices (SPMDs), solid phase microextraction (SPME) and polyethylene devices (PEDs), provide innovative tools for measuring hydrophobic organic contaminants (HOCs) originating from contaminated waters and sediments. Because the...

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.

Nanoporous array anodic titanium-supported co-polymeric ionic liquids as high performance solid-phase microextraction sorbents for hydrogen bonding compounds.

PubMed

Jia, Jing; Liang, Xiaojing; Wang, Licheng; Guo, Yong; Liu, Xia; Jiang, Shengxiang

2013-12-13

A nanoporous array anodic titanium-supported co-polymeric ionic liquids (NAAT/PILs) solid-phase microextraction (SPME) fiber was prepared in situ on the titanium wire. NAAT was selected as the substrate, in view of its high surface-to-volume ratio, easy preparation, mechanical stability, and rich titanol groups on its surface which can anchor silica coupling agent containing vinyl and then introduce ionic liquid copolymers as sorbents. In this work, 1-vinyl-3-nonanol imidazolium bromide ([C9OHVIm]Br) and 1,4-di(3-vinylimidazolium) butane dibromide ([(VIM)2C4]2[Br]) were synthesized and used as monomer and crosslinker, respectively. Extraction properties of the NAAT/PILs fiber for polar alcohols and volatile fatty acids (VFAs) in aqueous matrix were examined using gaseous sampling-SPME (GS-SPME) and headspace SPME (HS-SPME) mode, respectively. Combining the superior properties of NAAT substrate and the strong hydrogen bond interaction of PILs to polar compounds, the NAAT/PILs SPME fiber showed much higher adsorption affinity to aliphatic alcohols than bare NAAT and pure PILs fibers. The detection limits (LOD) of established GS-SPME-GC-FID method are in the range of 0.35-17.30ngL(-1) with a linear range from 0.01 to 500ngmL(-1). Also, it showed high extraction performance toward volatile fatty acids (VFAs) compounds from aqueous matrix. Under the optimized SPME conditions, wide linear ranges were obtained with correlation coefficients (R(2)) greater than 0.99 and limits of detection were in the range of 0.85-8.74ngL(-1). Moreover, real-world samples were analyzed and good results were obtained. Copyright © 2013. Published by Elsevier B.V.

Headspace solid-phase microextraction (HS-SPME) combined with GC-MS as a process analytical technology (PAT) tool for monitoring the cultivation of C. tetani.

PubMed

Ghader, Masoud; Shokoufi, Nader; Es-Haghi, Ali; Kargosha, Kazem

2018-04-15

Vaccine production is a biological process in which variation in time and output is inevitable. Thus, the application of Process Analytical Technologies (PAT) will be important in this regard. Headspace solid - phase microextraction (HS-SPME) coupled with GC-MS can be used as a PAT for process monitoring. This method is suitable to chemical profiling of volatile organic compounds (VOCs) emitted from microorganisms. Tetanus is a lethal disease caused by Clostridium tetani (C. tetani) bacterium and vaccination is an ultimate way to prevent this disease. In this paper, SPME fiber was used for the investigation of VOCs emerging from C. tetani during cultivation. Different types of VOCs such as sulfur-containing compounds were identified and some of them were selected as biomarkers for bioreactor monitoring during vaccine production. In the second step, the portable dynamic air sampling (PDAS) device was used as an interface for sampling VOCs by SPME fibers. The sampling procedure was optimized by face-centered central composite design (FC-CCD). The optimized sampling time and inlet gas flow rates were 10 min and 2 m L s -1 , respectively. PDAS was mounted in exhausted gas line of bioreactor and 42 samples of VOCs were prepared by SPME fibers in 7 days during incubation. Simultaneously, pH and optical density (OD) were evaluated to cultivation process which showed good correlations with the identified VOCs (>80%). This method could be used for VOCs sampling from off-gas of a bioreactor to monitoring of the cultivation process. Copyright © 2018. Published by Elsevier B.V.

A new dispersive liquid-liquid microextraction using ionic liquid based microemulsion coupled with cloud point extraction for determination of copper in serum and water samples.

PubMed

Arain, Salma Aslam; Kazi, Tasneem Gul; Afridi, Hassan Imran; Arain, Mariam Shahzadi; Panhwar, Abdul Haleem; Khan, Naeemullah; Baig, Jameel Ahmed; Shah, Faheem

2016-04-01

A simple and rapid dispersive liquid-liquid microextraction procedure based on ionic liquid assisted microemulsion (IL-µE-DLLME) combined with cloud point extraction has been developed for preconcentration copper (Cu(2+)) in drinking water and serum samples of adolescent female hepatitits C (HCV) patients. In this method a ternary system was developed to form microemulsion (µE) by phase inversion method (PIM), using ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([C4mim][PF6]) and nonionic surfactant, TX-100 (as a stabilizer in aqueous media). The Ionic liquid microemulsion (IL-µE) was evaluated through visual assessment, optical light microscope and spectrophotometrically. The Cu(2+) in real water and aqueous acid digested serum samples were complexed with 8-hydroxyquinoline (oxine) and extracted into IL-µE medium. The phase separation of stable IL-µE was carried out by the micellar cloud point extraction approach. The influence of of different parameters such as pH, oxine concentration, centrifugation time and rate were investigated. At optimized experimental conditions, the limit of detection and enhancement factor were found to be 0.132 µg/L and 70 respectively, with relative standard deviation <5%. In order to validate the developed method, certified reference materials (SLRS-4 Riverine water) and human serum (Sero-M10181) were analyzed. The resulting data indicated a non-significant difference in obtained and certified values of Cu(2+). The developed procedure was successfully applied for the preconcentration and determination of trace levels of Cu(2+) in environmental and biological samples. Copyright © 2015 Elsevier Inc. All rights reserved.

In situ metathesis reaction combined with liquid-phase microextraction based on the solidification of sedimentary ionic liquids for the determination of pyrethroid insecticides in water samples.

PubMed

Hu, Lu; Zhang, Panjie; Shan, Wanyu; Wang, Xuan; Li, Songqing; Zhou, Wenfeng; Gao, Haixiang

2015-11-01

A novel dispersion liquid-liquid microextraction method based on the solidification of sedimentary ionic liquids (SSIL-DLLME), in which an in situ metathesis reaction forms an ionic liquid (IL) extraction phase, was developed to determine four pyrethroid insecticides (i.e., permethrin, cyhalothrin, fenpropathrin, and transfluthrin) in water followed by separation using high-performance liquid chromatography. In the developed method, in situ DLLME was used to enhance the extraction efficiency and yield. After centrifugation, the extraction solvent, tributyldodecylphosphonium hexafluorophosphate ([P44412][PF6]), was easily collected by solidification in the bottom of the tube. The effects of various experimental parameters, the quantity of tributyldodecylphosphonium bromide ([P44412]Br), the molar ratio of [P44412]Br to potassium hexafluorophosphate (KPF6), the ionic strength, the temperature of the sample solution, and the centrifugation time, were optimized using a Plackett-Burman design to identify the significant factors that affected the extraction efficiency. These significant factors were then optimized using a central composite design. Under the optimized conditions, the recoveries of the four pyrethroid insecticides at four spiked levels ranged from 87.1% to 101.7%, with relative standard deviations (RSDs) ranging from 0.1% to 5.5%. At concentration levels between 1 and 500 µg/L, good linearity was obtained, with coefficients of determination greater than 0.9995. The limits of detection (LODs) for the four pyrethroid insecticides were in the range of 0.71-1.54 µg/L. The developed method was then successfully used for the determination of pyrethroid insecticides in environmental samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Development of new method of δ13C measurement for trace hydrocarbons in natural gas using solid phase micro-extraction coupled to gas chromatography isotope ratio mass spectrometry.

PubMed

Li, Zhongping; Wang, Xibin; Li, Liwu; Zhang, Mingjie; Tao, Mingxin; Xing, Lantian; Cao, Chunhui; Xia, Yanqing

2014-11-01

Compound specific isotope analysis (CSIA) of normal-level hydrocarbons (C 1 -C 4 ) in natural gas is often successfully used in natural gas origin identification and classification, but little progress so far has been made for trace level hydrocarbons (C 5 -C 14 ) in natural gas. In this study, we developed a method for rapid analysis of carbon isotopic ratios for trace hydrocarbons in natural gas samples. This method can be described as a combined approach characterized by solid phase micro-extraction (SPME) technique coupled to gas chromatography isotope ratio mass spectrometry (GC/IRMS). In this study, the CAR-PDMS fiber was chosen as the SPME adsorptive material after comparative experiments with other four fibers, and the parameters, including equilibration time, extraction temperature and desorption time, for efficient extraction of trace hydrocarbons were systematically optimized. The results showed the carbon isotopic fractionation was not observed as a function of equilibration time and extraction temperature. And the δ 13 C signatures determined by SPME-GC/IRMS were in good agreement with the known δ 13 C values of C 5 -C 14 measured by GC-IRMS, and the accuracy is generally within ±0.5‰. Five natural gas samples were analyzed using this method, and the δ 13 C values for C 5 -C 14 components were obtained with satisfied repeatability. The SPME-GC/IRMS approach fitted with CAR-PDMS fiber is well suited for the preconcentration of trace hydrocarbons and provides so far the most reliable carbon isotopic analysis for trace compounds in natural gas. Published by Elsevier B.V.

Evaluation of volatile metabolites as markers in Lycopersicon esculentum L. cultivars discrimination by multivariate analysis of headspace solid phase microextraction and mass spectrometry data.

PubMed

Figueira, José; Câmara, Hugo; Pereira, Jorge; Câmara, José S

2014-02-15

To gain insights on the effects of cultivar on the volatile metabolomic expression of different tomato (Lycopersicon esculentum L.) cultivars--Plum, Campari, Grape, Cherry and Regional, cultivated under similar edafoclimatic conditions, and to identify the most discriminate volatile marker metabolites related to the cultivar, the chromatographic profiles resulting from headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-qMS) analysis, combined with multivariate analysis were investigated. The data set composed by the 77 volatile metabolites identified in the target tomato cultivars, 5 of which (2,2,6-trimethylcyclohexanone, 2-methyl-6-methyleneoctan-2-ol, 4-octadecyl-morpholine, (Z)-methyl-3-hexenoate and 3-octanone) are reported for the first time in tomato volatile metabolomic composition, was evaluated by chemometrics. Firstly, principal component analysis was carried out in order to visualise data trends and clusters, and then, linear discriminant analysis in order to detect the set of volatile metabolites able to differentiate groups according to tomato cultivars. The results obtained revealed a perfect discrimination between the different Lycopersicon esculentum L. cultivars considered. The assignment success rate was 100% in classification and 80% in prediction ability by using "leave-one-out" cross-validation procedure. The volatile profile was able to differentiate all five cultivars and revealed complex interactions between them including the participation in the same biosynthetic pathway. The volatile metabolomic platform for tomato samples obtained by HS-SPME/GC-qMS here described, and the interrelationship detected among the volatile metabolites can be used as a roadmap for biotechnological applications, namely to improve tomato aroma and their acceptance in the final consumer, and for traceability studies. Copyright © 2013 Elsevier Ltd. All rights reserved.

Quantification of selected volatile organic compounds in human urine by gas chromatography selective reagent ionization time of flight mass spectrometry (GC-SRI-TOF-MS) coupled with head-space solid-phase microextraction (HS-SPME).

PubMed

Mochalski, Paweł; Unterkofler, Karl

2016-08-07

Selective reagent ionization time of flight mass spectrometry with NO(+) as the reagent ion (SRI-TOF-MS(NO(+))) in conjunction with gas chromatography (GC) and head-space solid-phase microextraction (HS-SPME) was used to determine selected volatile organic compounds in human urine. A total of 16 volatiles exhibiting high incidence rates were quantified in the urine of 19 healthy volunteers. Amongst them there were ten ketones (acetone, 2-butanone, 3-methyl-2-butanone, 2-pentanone, 3-methyl-2-pentanone, 4-methyl-2-pentanone, 2-hexanone, 3-hexanone, 2-heptanone, and 4-heptanone), three volatile sulphur compounds (dimethyl sulfide, allyl methyl sulfide, and methyl propyl sulfide), and three heterocyclic compounds (furan, 2-methylfuran, 3-methylfuran). The concentrations of the species under study varied between 0.55 nmol L(-1) (0.05 nmol mmol(-1)creatinine) for allyl methyl sulfide and 11.6 μmol L(-1) (1.54 μmol mmol(-1)creatinine) for acetone considering medians. Limits of detection (LODs) ranged from 0.08 nmol L(-1) for allyl methyl sulfide to 1.0 nmol L(-1) for acetone and furan (with RSDs ranging from 5 to 9%). The presented experimental setup assists both real-time and GC analyses of volatile organic compounds, which can be performed consecutively using the same analytical system. Such an approach supports the novel concept of hybrid volatolomics, an approach which combines VOC profiles obtained from two or more body fluids to improve and complement the chemical information on the physiological status of an individual.

Online analysis of five organic ultraviolet filters in environmental water samples using magnetism-enhanced monolith-based in-tube solid phase microextraction coupled with high-performance liquid chromatography.

PubMed

Mei, Meng; Huang, Xiaojia

2017-11-24

Due to the endocrine disrupting properties, organic UV filters have been a great risk for humans and other organisms. Therefore, development of accurate and effective analytical methods is needed for the determination of UV filters in environmental waters. In this work, a fast, sensitive and environmentally friendly method combining magnetism-enhanced monolith-based in-tube solid phase microextraction with high-performance liquid chromatography with diode array detection (DAD) (ME-MB-IT/SPME-HPLC-DAD) for the online analysis of five organic UV filters in environmental water samples was developed. To extract UV filters effectively, an ionic liquid-based monolithic capillary column doped with magnetic nanoparticles was prepared by in-situ polymerization and used as extraction medium of online ME-MB-IT/SPME-HPLC-DAD system. Several extraction conditions including the intensity of magnetic field, sampling and desorption flow rate, volume of sample and desorption solvent, pH value and ionic strength of sample matrix were optimized thoroughly. Under the optimized conditions, the extraction efficiencies for five organic UV filters were in the range of 44.0-100%. The limits of detection (S/N=3) and limits of quantification (S/N=10) were 0.04-0.26μg/L and 0.12-0.87μg/L, respectively. The precisions indicated by relative standard deviations (RSDs) were less than 10% for both intra- and inter-day variabilities. Finally, the developed method was successfully applied to the determination of UV filters in three environmental water samples and satisfactory results were obtained. Copyright © 2017 Elsevier B.V. All rights reserved.

An improved method for the analysis of 2-aminoacetophenone in wine based on headspace solid-phase microextraction and heart-cut multidimensional gas chromatography with selective detection by tandem mass spectrometry.

PubMed

Schmarr, Hans-Georg; Keiser, Jutta; Krautwald, Susann

2016-12-16

Heart-cut multidimensional gas chromatography coupled to selective mass spectrometric detection (H/C MDGC-MS-MS) was shown to be a suitable combination for analysis of the key component for the wine off-flavor named "atypical aging off-flavor" (german: "Untypische Alterungsnote", UTA), 2-aminoacetophenone (2-AAP). Headspace solid phase microextraction (HS-SPME) was applied as an easy to automate sample preparation step suiting routine control situations. During method development two critical aspects were found, of which one is the chemical degradation of the neat substance, leading to signal reduction and a false response behavior. A second aspect is the pH stability of the deuterated isotopologue 1-(2-aminophenyl)-2,2,2-trideuterio-ethanone (2-AAP-d3) used for quantification via a stable isotope dilution assay. Despite an earlier suggestion to increase the extractable amount of 2-AAP and its isotopic standard in the headspace, alkalization of 2-AAP-d3 containing aqueous samples were found to be critical. In such a milieu a deuterium exchange can then cause erroneous quantitative results. The method proposed in our study thus uses native wine pH conditions and proved to be suitable for routine control with respect to the detection of the "atypical aging off-flavor" in wine at concentration levels below its sensory threshold of about 1μgL -1 . Good linearity was obtained in the calibrated range from 0.1-8μgL -1 (y=1,2338x+0,1029, R=0,9985) with limits of detection or quantification being 0.01 and 0.14μg/L, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

A salting out system for improving the efficiency of the headspace solid-phase microextraction of short and medium chain free fatty acids.

PubMed

Fiorini, Dennis; Pacetti, Deborah; Gabbianelli, Rosita; Gabrielli, Serena; Ballini, Roberto

2015-08-28

Given the importance of short and medium chain free fatty acids (FFAs) in several fields, this study sought to improve the extraction efficiency of the solid-phase microextraction (SPME) of FFAs by evaluating salting out agents that appear promising for this application. The salts ammonium sulfate ((NH4)2SO4) and sodium dihydrogen phosphate (NaH2PO4) were tried on their own and in combination (3.7/1), in four different total amounts, as salting out agents in the headspace-SPME-gas chromatographic (HS-SPME-GC) analysis of the FFAs from acetic acid (C2) to decanoic acid (C10). Their performance in a model system of an aqueous standard mixture of FFAs at a pH of 3.5 was compared to that of the more commonly used sodium chloride (NaCl) and sodium sulfate (Na2SO4). All of the salts and salt systems evaluated, in proper amount, gave improved results compared to NaCl (saturated), which instead gave interesting results only for the least volatile FFAs C8 and C10. For C2-C6, the salt system that gave the best results compared to NaCl was (NH4)2SO4/NaH2PO4, in the highest of the four amounts evaluated, with factor increases between 1.2 and 4.1-fold, and NaH2PO4, between 1.0 and 4.3-fold. The SPME extraction efficiency given by the mixture (NH4)2SO4/NaH2PO4 was also assessed on biological and food samples, confirming that overall it performed better than NaCl. Copyright © 2015 Elsevier B.V. All rights reserved.

[Determination of ten photoinitiators in fruit juices and tea beverages by solid-phase micro-extraction coupled with gas chromatography/mass spectrometry].

PubMed

Liu, Pengyan; Chen, Yanjie; Zhao, Chunxia; Tian, Lei

2013-12-01

A method for the determination of ten photoinitiators (PIs), benzophenone, ethyl 4-dimethylaminobenzoate, 1-hydroxycyclohexyl-phenylketone, 4-methylbenzophenone, 2-ethylhexyl-4-dimethylaminobenzoate, 4-chlorobenzophenone, 2-chlorothioxanthone, 2-isopropylthio-xanthone, 2,2-dimethoxy-2-phenylacetophenone, methyl 2-benzoylbenzoate, in 13 kinds of fruit juice and 3 kinds of tea beverage has been established, using solid-phase micro-extraction (SPME) combined with chromatography/mass spectrometry (GC/MS). At first, the major factors of SPME, extraction time and temperature, were studied through orthogonal experiment. Then the optimal operation conditions were obtained via the refinement of various factors. After the sample was extracted by SPME, it was desorbed for target analytes in sampling inlet for 3 min, and separated on an HP-5MS column, then detected by MS in selected ion monitoring mode, and quantified through calibration curve. The working curves were obtained using sample matrix in order to eliminate the matrix interference. The linear range was from 0.3 microg/L to 60 microg/L and the detection limit range was from 3 ng/L to 16 ng/L. The samples were determined five times with four different spiked levels individually and the relative standard deviations of all the samples were less than 14.5%. This determination method was applied in 16 kinds of packed beverages with different brands and different species. Benzophenone had been detected from all the samples. 4-Methylbenzophenone, 2-ethylhexyl-4-dimethylaminobenzoate, 2-isopropylthioxanthone, 1-hydroxycyclohexyl-phenylketone and 2-chlorothioxanthone had been detected from a portion of samples. Simultaneous determination was achieved for the ten PIs. These results provide a reference to determine the PIs migrated from packing materials in beverage. This method is simple, high sensitive and non-polluting.

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.

Simultaneous analysis of organochlorine pesticides and polychlorinated biphenyls in air samples by using accelerated solvent extraction (ASE) and solid-phase micro-extraction (SPME) coupled to gas chromatography dual electron capture detection.

PubMed

Mokbel, Haifaa; Al Dine, Enaam Jamal; Elmoll, Ahmad; Liaud, Céline; Millet, Maurice

2016-04-01

An analytical method associating accelerated solvent extraction (ASE) and solid-phase micro-extraction (SPME) in immersion mode combined with gas chromatography dual electrons capture detectors (SPME-GC-2ECD) has been developed and studied for the simultaneous determination of 19 organochlorine pesticides (OCPs) and 22 polychlorinated biphenyls (PCBs) in air samples (active and XAD-2 passive samplers). Samples were extracted with ASE with acetonitrile using the following conditions: temperature, 150 °C; pressure, 1500 psi; static, 15 min; cycles, 3; purge, 300 s; flush, 100 %. Extracts were reduced to 1 mL, and 500 μL of this extract, filled with deionised water, was subject to SPME extraction. Experimental results indicated that the proposed method attained the best extraction efficiency under the optimised conditions: extraction of PCB-OCP mixture using 100-μm PDMS fibre at 80 °C for 40 min with no addition of salt. The performance of the proposed ASE-SPME-GC-2ECD methodology with respect to linearity, limit of quantification and detection was evaluated by spiking of XAD-2 resin with target compounds. The regression coefficient (R (2)) of most compounds was found to be high of 0.99. limits of detection (LODs) are between 0.02 and 4.90 ng m(-3), and limits of quantification (LOQs) are between 0.05 and 9.12 ng m(-3) and between 0.2 and 49 ng/sampler and 0.52 and 91 ng/sampler, respectively, for XAD-2 passive samplers. Finally, a developed procedure was applied to determine selected PCBs and OCPs in the atmosphere.

Expanding the use of polymeric ionic liquids in headspace solid-phase microextraction: Determination of ultraviolet filters in water samples.

PubMed

Trujillo-Rodríguez, María J; Nan, He; Anderson, Jared L

2018-03-09

Three crosslinked polymeric ionic liquid (PIL) sorbent coatings were used in headspace solid-phase microextraction for the determination of a group of ultraviolet filters. The developed crosslinked PIL-based materials include two polycations and a double confined PIL. The method, in combination with gas chromatography-mass spectrometry, is simple, solvent free, and does not require of any derivatization step. After proper optimization of the methodologies with each developed fiber, the analytical performance was compared with a commercial polyacrylate fiber. A study of the normalized calibration slopes, obtained by dividing the calibration slope of each analyte by the coating volume, revealed that the crosslinked fibers can be used as alternatives to commercial fibers for the determination of the selected group of compounds. In particular, the coating nature of the PIL containing the 1-vinylbenzyl-3-hexadecylimidazolium bis[(trifluoromethyl)sulfonyl]imide IL as monomer and the 1,12-di(3-vinylbenzylimidazolium)dodecane bis[(trifluoromethyl)sulfonyl]imide IL as crosslinker is the most suitable for the extraction of the selected compounds despite their coating volume, being 3.6 times lower than the commercial polyacrylate fiber. For this fiber, wide linear ranges, correlation coefficients higher than 0.990, limits of detection ranging from 2.8 ng L -1 to 26 ng L -1 and relative standard deviations ranging from 2.5 to 15% were achieved. Finally, all proposed PIL-based fibers were applied towards the analysis of tap water, pool water and lake water, with the majority of the ultraviolet filters being detected and quantified in the last two types of samples. Copyright © 2018 Elsevier B.V. All rights reserved.

[Synchronous extraction and determination of phenoxy acid herbicides in water by on-line monolithic solid phase microextraction-high performance liquid chromatography].

PubMed

Wang, Jiabin; Wu, Fangling; Zhao, Qi

2015-08-01

A C18 monolithic capillary column was utilized as the solid phase microextraction column to construct an in-tube SPME-HPLC system which was used to simultaneously extract and detect five phenoxy acid herbicides, including 2,4-dichlorophenoxyacetic acid (2,4-D), 2- (2-chloro)-phenoxy propionic acid (2,2-CPPA), 2-(3-chloro)-phenoxy propionic acid (2,3- CPPA), phenoxy propionic acid (PPA) and 2-(2,4-dichlorophenoxy) propionic acid (2,4-DP). The operating parameters of the in-tube SPME-HPLC system, including the length of the monolithic column, the sampling flow rate, the sampling time, the elution flow rate and the elution time, had been investigated in detail. The optimized operating parameters of the in-tube SPME-HPLC system were as follow: the length of the monolithic column was 20 cm, the sampling flow rate was 0. 04 mL/min, sampling time was 13 min; the elution flow rate was 0.02 mL/min, elution time was 5 min. Under the optimized conditions, the detection limits of the five phenoxy acid herbicides were as follows: 9 µg/L for PPA, 4 µg/L for 2,2-CPPA, 4 µg/L for 2,3-CPPA, 5 µg/L for 2,4-D, 5 µg/L for 2,4-DP. Compared with the HPLC method with direct injection, the combined system showed a good enrichment factors to the analytes. The recoveries of the five phenoxy acid herbicides were between 79.0% and 98.0% (RSD ≤ 3.9%). This method was successfully used to detect the five phenoxy acid herbicides in water samples with satisfactory results.

Solid-phase microextraction of methadone in urine samples by electrochemically co-deposited sol-gel/Cu nanocomposite fiber.

PubMed

Mohammadiazar, Sirwan; Hasanli, Fateme; Maham, Mehdi; Payami Samarin, Somayeh

2017-08-01

Electrochemically co-deposited sol-gel/Cu nanocomposites have been introduced as a novel, simple and single-step technique for preparation of solid-phase microextraction (SPME) coating to extract methadone (MDN) (a synthetic opioid) in urine samples. The porous surface structure of the sol-gel/Cu nanocomposite coating was revealed by scanning electron microscopy. Direct immersion SPME followed by HPLC-UV determination was employed. The factors influencing the SPME procedure, such as the salt content, desorption solvent type, pH and equilibration time, were optimized. The best conditions were obtained with no salt content, acetonitrile as desorption solvent type, pH 9 and 10 min equilibration time. The calibration graphs for urine samples showed good linearity. The detection limit was about 0.2 ng mL -1 . Also, the novel method for preparation of nanocomposite fiber was compared with previously reported techniques for MDN determination. The results show that the novel nanocomposite fiber has relatively high extraction efficiency. Copyright © 2016 John Wiley & Sons, Ltd.

Optimization of headspace solid-phase microextraction by means of an experimental design for the determination of methyl tert.-butyl ether in water by gas chromatography-flame ionization detection.

PubMed

Dron, Julien; Garcia, Rosa; Millán, Esmeralda

2002-07-19

A procedure for determination of methyl tert.-butyl ether (MTBE) in water by headspace solid-phase microextraction (HS-SPME) has been developed. The analysis was carried out by gas chromatography with flame ionization detection. The extraction procedure, using a 65-microm poly(dimethylsiloxane)-divinylbenzene SPME fiber, was optimized following experimental design. A fractional factorial design for screening and a central composite design for optimizing the significant variables were applied. Extraction temperature and sodium chloride concentration were significant variables, and 20 degrees C and 300 g/l were, respectively chosen for the best extraction response. With these conditions, an extraction time of 5 min was sufficient to extract MTBE. The calibration linear range for MTBE was 5-500 microg/l and the detection limit 0.45 microg/l. The relative standard deviation, for seven replicates of 250 microg/l MTBE in water, was 6.3%.

Analysis of potassium formate in airport storm water runoff by headspace solid-phase microextraction and gas chromatography-mass spectrometry.

PubMed

Fries, Elke; Klasmeier, Jörg

2009-01-30

Potassium formate was extracted from airport storm water runoff by headspace solid-phase microextraction (HS-SPME) and analyzed by GC-MS. Formate was transformed to formic acid by adding phosphoric acid. Subsequently, formic acid was derivatized to methyl formate by adding methanol. Using sodium [(2)H]formate (formate-d) as an internal standard, the relative standard deviation of the peak area ratio of formate (m/z 60) and formate-d (m/z 61) was 0.6% at a concentration of 208.5 mg L(-1). Calibration was linear in the range of 0.5-208.5 mg L(-1). The detection limit calculated considering the blank value was 0.176 mg L(-1). The mean concentration of potassium formate in airport storm water runoff collected after surface de-icing operations was 86.9 mg L(-1) (n=11) with concentrations ranging from 15.1 mg L(-1) to 228.6 mg L(-1).

Highly porous solid-phase microextraction fiber coating based on poly(ethylene glycol)-modified ormosils synthesized by sol-gel technology.

PubMed

da Costa Silva, Raquel Gomes; Augusto, Fabio

2005-04-22

The preparation and characteristics of solid-phase microextraction (SPME) fibers coated with Carbowax 20M ormosil (organically modified silica) are described here. Raw fused silica fibers were coated with Carbowax 20M-modified silica using sol-gel process. Scanning electron micrographs of fibers revealed a highly porous, sponge-like coating with an average thickness of (8 +/- 1) microm. The sol-gel Carbowax fibers were compared to commercial fibers coated with 100 microm polydimethylsiloxane (PDMS) and 65 microm Carbowax-divinylbenzene (DVB). Shorter equilibrium times were possible with the sol-gel Carbowax fiber: for headspace extraction of the test analytes, they ranged from less than 3 min for benzene to 15 min for o-xylene. Extraction efficiencies of the sol-gel Carbowax fiber were superior to those of conventional fibers: for o-xylene, the extracted masses were 230 and 540% of that obtained with 100 microm PDMS and 65 microm Carbowax-DVB fibers, respectively.

[The progress in speciation analysis of trace elements by atomic spectrometry].

PubMed

Wang, Zeng-Huan; Wang, Xu-Nuo; Ke, Chang-Liang; Lin, Qin

2013-12-01

The main purpose of the present work is to review the different non-chromatographic methods for the speciation analysis of trace elements in geological, environmental, biological and medical areas. In this paper, the sample processing methods in speciation analysis were summarized, and the main strategies for non-chromatographic technique were evaluated. The basic principles of the liquid extractions proposed in the published literatures recently and their advantages and disadvantages were discussed, such as conventional solvent extraction, cloud point extraction, single droplet microextraction, and dispersive liquid-liquid microextraction. Solid phase extraction, as a non-chromatographic technique for speciation analysis, can be used in batch or in flow detection, and especially suitable for the online connection to atomic spectrometric detector. The developments and applications of sorbent materials filled in the columns of solid phase extraction were reviewed. The sorbents include chelating resins, nanometer materials, molecular and ion imprinted materials, and bio-sorbents. Other techniques, e. g. hydride generation technique and coprecipitation, were also reviewed together with their main applications.

A multiple hollow fibre liquid-phase microextraction method for the determination of halogenated solvent residues in olive oil.

PubMed

Manso, J; García-Barrera, T; Gómez-Ariza, J L; González, A G

2014-02-01

The present paper describes a method based on the extraction of analytes by multiple hollow fibre liquid-phase microextraction and detection by ion-trap mass spectrometry and electron capture detectors after gas chromatographic separation. The limits of detection are in the range of 0.13-0.67 μg kg(-1), five orders of magnitude lower than those reached with the European Commission Official method of analysis, with three orders of magnitude of linear range (from the quantification limits to 400 μg kg(-1) for all the analytes) and recoveries in fortified olive oils in the range of 78-104 %. The main advantages of the analytical method are the absence of sample carryover (due to the disposable nature of the membranes), high enrichment factors in the range of 79-488, high throughput and low cost. The repeatability of the analytical method ranged from 8 to 15 % for all the analytes, showing a good performance.

Determination of roasted pistachio (Pistacia vera L.) key odorants by headspace solid-phase microextraction and gas chromatography-olfactometry.

PubMed

Aceña, Laura; Vera, Luciano; Guasch, Josep; Busto, Olga; Mestres, Montserrat

2011-03-23

Key odorants in roasted pistachio nuts have been determined for the first time. Two different pistachio varieties (Fandooghi and Kerman) have been analyzed by means of headspace solid-phase microextraction (HS-SPME) and gas chromatography-olfactometry (GCO). The aroma extract dilution analyses (AEDA) applied have revealed 46 and 41 odor-active regions with a flavor dilution (FD) factor≥64 for the Fandooghi and the Kerman varieties, respectively, and 39 of them were related to precisely identified compounds. These included esters, pyrazines, aldehydes, acids, furans, and phenols. The results show that the Fandooghi variety presents, not only more odor-active regions but also higher FD factors than the Kerman variety that can lead to the conclusion that the first variety has a richer aromatic profile than the second one. The descriptive sensory analysis (DSA) showed that the roasted, chocolate/coffee, and nutty attributes were rated significantly higher in the Fandooghi variety, whereas the green attribute was significantly higher in the Kerman one.

[Developments in preparation and experimental method of solid phase microextraction fibers].

PubMed

Yi, Xu; Fu, Yujie

2004-09-01

Solid phase microextraction (SPME) is a simple and effective adsorption and desorption technique, which concentrates volatile or nonvolatile compounds from liquid samples or headspace of samples. SPME is compatible with analyte separation and detection by gas chromatography, high performance liquid chromatography, and other instrumental methods. It can provide many advantages, such as wide linear scale, low solvent and sample consumption, short analytical times, low detection limits, simple apparatus, and so on. The theory of SPME is introduced, which includes equilibrium theory and non-equilibrium theory. The novel development of fiber preparation methods and relative experimental techniques are discussed. In addition to commercial fiber preparation, different newly developed fabrication techniques, such as sol-gel, electronic deposition, carbon-base adsorption, high-temperature epoxy immobilization, are presented. Effects of extraction modes, selection of fiber coating, optimization of operating conditions, method sensitivity and precision, and systematical automation, are taken into considerations in the analytical process of SPME. A simple perspective of SPME is proposed at last.

Quantitative analysis of 2-furfural and 5-methylfurfural in different Italian vinegars by headspace solid-phase microextraction coupled to gas chromatography-mass spectrometry using isotope dilution.

PubMed

Giordano, Lucia; Calabrese, Roberto; Davoli, Enrico; Rotilio, Domenico

2003-10-31

A new method was developed for the determination of 2-furfural (2-F) and 5-methylfurfural (5-MF), two products of Maillard reaction in vinegar, with head-space solid-phase microextraction (HS-SPME) coupled to gas chromatography-mass spectrometry (GC-MS). A divinylbenzene (DVB)/carboxen (CAR)/polydimethylsiloxane (PDMS) fibre was used and SPME conditions were optimised, studying ionic strength effect, temperature effect and adsorption time. Both analytes were determined by calibration established on 2-furfural-d4 (2-F-d4). The method showed good linearity in the range studied (from 16 to 0.12 mg/l), with a regression coefficient r2 of 0.9999. Inter-batch precision and accuracy were found between 14.9 and 6.0% and between -11.7 and 0.2%, respectively. Detection limit was 15 microg/l. The method is simple and accurate and it has been applied to a series of balsamic and non-balsamic vinegars.

Determination of Lactones in Wines by Headspace Solid-Phase Microextraction and Gas Chromatography Coupled with Mass Spectrometry

PubMed Central

Pérez-Olivero, S. J.; Pérez-Pont, M. L.; Conde, J. E.; Pérez-Trujillo, J. P.

2014-01-01

Application of headspace solid-phase microextraction (HS-SPME) coupled with high-resolution gas chromatographic (HRGC) analysis was studied for determining lactones in wines. Six different SPME fibers were tested, and the influence of different factors such as temperature and time of desorption, ionic strength, time of extraction, content of sugar, ethanol, tannins and anthocyanins, and pH and influence of SO2 were studied. The proposed HS-SPME-GC method is an appropriate technique for the quantitative analysis of γ-butyrolactone, γ-hexalactone, trans-whiskey lactone, γ-octalactone, cis-whiskey lactone, γ-nonalactone, γ-decalactone, δ-decalactone, and γ-undecalactone in wines. Method reproducibility and repeatability ranged between 0.6 and 5.2% for all compounds. Detection limit for γ-butyrolactone was 0.17 mg/L and a few μg/L for the rest of the compounds. The optimized method has been applied to several wine samples. PMID:24782943

Evaluation of a headspace solid-phase microextraction method for the analysis of ignitable liquids in fire debris.

PubMed

Fettig, Ina; Krüger, Simone; Deubel, Jan H; Werrel, Martin; Raspe, Tina; Piechotta, Christian

2014-05-01

The chemical analysis of fire debris represents a crucial part in fire investigations to determine the cause of a fire. A headspace solid-phase microextraction (HS-SPME) procedure for the detection of ignitable liquids in fire debris using a fiber coated with a mixture of three different sorbent materials (Divinylbenzene/Carboxen/Polydimethylsiloxane, DVB/CAR/PDMS) is described. Gasoline and diesel fuel were spiked upon a preburnt matrix (wood charcoal), extracted and concentrated with HS-SPME and then analyzed with gas chromatography/mass spectrometry (GC/MS). The experimental conditions--extraction temperature, incubation and exposure time--were optimized. To assess the applicability of the method, fire debris samples were prepared in the smoke density chamber (SDC) and a controlled-atmosphere cone calorimeter. The developed methods were successfully applied to burnt particleboard and carpet samples. The results demonstrate that the procedure that has been developed here is suitable for detecting these ignitable liquids in highly burnt debris. © 2013 American Academy of Forensic Sciences.

Furanic compounds and furfural in different coffee products by headspace liquid-phase micro-extraction followed by gas chromatography-mass spectrometry: survey and effect of brewing procedures.

PubMed

Chaichi, Maryam; Ghasemzadeh-Mohammadi, Vahid; Hashemi, Maryam; Mohammadi, Abdorreza

2015-01-01

In this study, the levels of furan, 2-methylfuran, 2,5-dimethylfuran, vinyl furan, 2-methoxymethyl-furan and furfural in different coffee products were evaluated. Simultaneous determination of these six furanic compounds was performed by a head space liquid-phase micro-extraction (HS-LPME) method. A total of 67 coffee powder samples were analysed. The effects of boiling and espresso-making procedures on the levels of furanic compounds were investigated. The results showed that different types of coffee samples contained different concentrations of furanic compounds, due to the various processing conditions such as temperature, degree of roasting and fineness of grind. Among the different coffee samples, the highest level of furan (6320 µg kg⁻¹) was detected in ground coffee, while coffee-mix samples showed the lowest furan concentration (10 µg kg⁻¹). Levels in brewed coffees indicated that, except for furfural, brewing by an espresso machine caused significant loss of furanic compounds.

Determination of 17 kinds of banned organochlorine pesticides in water by activated carbon fiber-solid phase microextraction coupled with GC-MS.

PubMed

Sun, Tonghua; Jia, Jinping; Zhong, Dengjie; Wang, Yalin

2006-02-01

Activated carbon fiber (ACF) as extraction fiber for solid-phase microextraction (SPME) and its application for the analysis of banned organochlorine pesticides (OCPs) were investigated. Firstly, ACF was activated by different concentration of zinc chloride, which indicated that ACF activated by 60% zinc chloride had a reasonable specific surface area, pore volume and pore distribution. Secondly, the parameters for the ACF-SPME procedure, the adsorption and desorption conditions, were also optimized when coupled with gas chromatography-mass spectrometry (GC-MS). Thirdly, the ACF-SPME was used to analyze 17 kinds of OCPs in water. The linearity of most pesticides was found to be between 0.2 and 50 microg/l with GC-MS under the selected ion monitoring (SIM) acquisition mode. The limits of detection (LOD) at the sub microg/l were obtained. The work demonstrated here shows that ACF is a promising alternative for the SPME procedure.

[Preparation of a novel activated carbon coating fiber for solid phase micro-extraction and its application for halocarbon compound analysis in water].

PubMed

Wang, Shutao; Wang, Yan; You, Hong; Liang, Zhihua

2004-09-01

A novel activated carbon coating fiber used for solid phase micro-extraction (SPME) was prepared using activated carbon powder and silica resin adhesive. The extraction properties of the novel activated carbon coating fiber were investigated. The results indicate that this coating fiber has high concentration ability, with enrichment factors for chloroform, carbon tetrachloride, trichloroethylene and tetrachloroethylene in the range of 13.8 to 18.7. The fiber is stable at temperature as high as 290 degrees C and it can be used for over 140 times at 250 degrees C. The activated carbon coating fiber was then applied to the analysis of the four halocarbon compounds mentioned above. A linear correlation with correlation coefficients between 0.995 2 and 0.999 4 and the detection limits between 0.008 and 0.05 microg/L were observed. The method was also applied to a real water sample analysis and the recoveries of these halocarbon compounds were from 95.5% to 104.6%.

Adjusted active carbon fibers for solid phase microextraction.

PubMed

Jia, Jinping; Feng, Xue; Fang, Nenghu; Wang, Yalin; Chen, Hongjin; Dan, Wu

2002-01-01

Adjusted active carbon fiber (AACF) was evaluated for Solid Phase Microextraction (SPME), which showed higher sensitivity and stability than traditional coating fibers. The characteristics of AACF result from two different activation methods (chemical and water vapor) and from variable activation conditions (temperature and time). The fiber treated by water vapor appears to have stronger affinity to polar compounds, while that treated by chemical activation appears to have stronger affinity to non-polar compounds. For different target compounds ranged from non-polar to polar, AACF design could be effective with specific selections and sensitivities. As applications in this paper, benzoic acid in soy sauce was extracted onto water-vapor-activated-fiber, then analyzed using gas chromatograph-mass spectrometer (GC-MS). The chemical-activated-fiber SPME was applied in the analysis of benzene series compounds (BTEX) in water matrix. Compared with standard carbon disulfide extraction method, chemical-activated-fiber SPME is more convenient due to its simple process and turns to be of relative low detection limits.

Solid-phase microextraction may catalize hydrogenation when using hydrogen as carrier in gas chromatography.

PubMed

Fiorini, D; Boarelli, M C

2016-07-01

When hydrogen is used as carrier gas, carbon-carbon double bonds may be hydrogenated in the hot gas chromatograph (GC) injector if introduced by solid-phase microextraction (SPME). SPME fibers coated with polydimethylsiloxane (PDMS)/carboxen/divinylbenzene (DVB), PDMS/carboxen, polyacrylate, PDMS/DVB and PDMS on fused silica, stableflex or metal alloy core have been tested with fatty acid methyl esters (FAMEs) from olive oil. Using coatings containing DVB, hydrogenation took place with high conversion rates (82.0-92.9%) independently of the core material. With all fibers having a metal core, hydrogenation was observed to a certain extent (27.4-85.3%). PDMS, PDMS/carboxen and polyacrylate coated fibers with a fused silica or stableflex core resulted in negligible hydrogenation (0.2-2.5%). The occurrence of hydrogenation was confirmed also with other substances containing carbon-carbon double bonds (n-alkenes, alkenoic acids, mono- and polyunsaturated fatty acid methyl and ethyl esters). Copyright © 2016 Elsevier B.V. All rights reserved.

Solid-phase microextraction for the determination of volatile compounds in the spoilage of raw ground beef.

PubMed

Pérez, Rosa Ana; Rojo, Maria Dolores; González, Gema; De Lorenzo, Cristina

2008-01-01

A method using solid-phase microextraction (SPME) and gas chromatography/mass spectrometry was developed and applied to the determination of volatile compounds generated in meat, at different times, from ground beef stored under refrigeration. Selection of the extractive fiber, extraction time, and headspace (HS) or direct extraction was optimized for the determination of volatile compounds from ground meat. Various fibers were investigated, and carboxen/polydimethylsiloxane was selected for these analyses. The HS analysis of the solid sample by HS-SPME produced a higher volatile signal than did direct-SPME. The meat samples were stored under refrigeration and analyzed after 0, 3, and 6 days of storage. These analyses at different times showed important changes in the volatile profile of the evaluated samples. The ketones 3-hydroxy-2-butanone and 2,3-butanedione, and the alcohol 3-methyl-1-butanol were the most representative compounds generated during the meat storage. In general, compounds associated with a butter off-flavor were detected during the storage of raw ground beef.

Rapid determination of octanol-water partition coefficient using vortex-assisted liquid-liquid microextraction.

PubMed

Román, Iván P; Mastromichali, Anna; Tyrovola, Konstantina; Canals, Antonio; Psillakis, Elefteria

2014-02-21

Vortex-assisted liquid-liquid microextraction (VALLME) coupled with high-performance liquid chromatography (HPLC) is proposed here for the rapid determination of octanol-water partitioning coefficients (Kow). VALLME uses vortex agitation, a mild emulsification procedure, to disperse microvolumes of octanol in the aqueous phase thus increasing the interfacial contact area and ensuring faster partitioning rates. With VALLME, 2min were enough to achieve equilibrium conditions between the octanolic and aqueous phases. Upon equilibration, separation was achieved using centrifugation and the octanolic microdrop was collected and analyzed in a HPLC system. Six model compounds with logKow values ranging between ∼0.5 and 3.5 were used during the present investigations. The proposed method produced logKow values that were consistent with previously published values and the recorded uncertainty was well within the acceptable log unit range. Overall, the key features of the proposed Kow determination procedure comprised speed, reliability, simplicity, low cost and minimal solvent consumption. Copyright © 2014 Elsevier B.V. All rights reserved.

MOF-5(Zn)-Fe2O4 nanocomposite based magnetic solid-phase microextraction followed by HPLC-UV for efficient enrichment of colchicine in root of colchicium extracts and plasma samples.

PubMed

Bahrani, Sonia; Ghaedi, Mehrorang; Dashtian, Kheibar; Ostovan, Abbas; Mansoorkhani, Mohammad Javad Khoshnood; Salehi, Amin

2017-11-01

In present work, facile method is developed for determination of colchicine in human plasma sample, autumn and spring root of colchicium extracts by ultrasound assisted dispersive magnetic solid phase microextraction followed by HPLC-UV method (UAD-MSPME-HPLC-UV). Magnetic (Fe 2 O 4 -nanoparticles) metal organic framework-5, (MOF-5(Zn)-Fe 2 O 4 NPs) was synthesized by dispersing MOF-5 and Fe(NO 3 ) 3 .9H 2 O in ethylene glycol (as capping agent) and NaOH (pH adjustment agent) by hydrothermal method. The prepared sorbent was characterized via XRD and SEM analysis and applied as magnetic solid phase in UAD-MSPME-HPLC-UV method. In this method, colchicine molecules were sorbed on MOF-5(Zn)-Fe 2 O 4 NPs sorbent by various mechanisms like ion exchange, hydrogen bonding and electrostatic, ᴨ-ᴨ, hard-hard and dipole-ion interaction followed by exposing sonication waves as incremental mass transfer agent and then the sorbent was separated from the sample matrix by an external magnetic fields. Subsequently, accumulated colchicine were eluted by small volume of desorption organic solvent. Influence of operational variables such as MOF-5(Zn)-Fe 2 O 4 NPs mass, volume of extracting solvent and sonication time on response property (recovery) were studied and optimized by central composite design (CCD) combined with desirability function (DF) approach. Under optimum condition, the method has wide linear calibration rang (0.5-1700ngmL -1 ) with reasonable detection limit (0.13ngmL -1 ) and R 2 =0.9971. Finally, the UAD-MSPME-HPLC-UV method was successfully applied for determination of colchicine autumn and spring root of colchicium extracts and plasma samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Hybrid silica monolith for microextraction by packed sorbent to determine drugs from plasma samples by liquid chromatography-tandem mass spectrometry.

PubMed

de Souza, Israel D; Domingues, Diego S; Queiroz, Maria E C

2015-08-01

The present study (1) reports on the synthesis of two hybrid silica monoliths functionalized with aminopropyl or cyanopropyl groups by the sol-gel process; (2) evaluates these monoliths as selective stationary phase for microextraction by packed sorbent (MEPS) to determine drugs in plasma samples via liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the multiple reactions monitoring (MRM) mode; and (3) discusses important factors related to the optimization of MEPS efficiency as well as the carryover effect. The prepared hybrid silica monoliths consisted of a uniform, porous, and continuous silica monolithic network. The structure of the aminopropyl hybrid silica monolith was more compact than the structure of the cyanopropyl hybrid silica monolith. The Fourier-transform infrared spectroscopy (FTIR) spectra of the hybrid silica monoliths displayed readily identifiable peaks, characteristic of the cyanopropyl and aminopropyl groups. Compared with the aminopropyl hybrid silica phase, the cyanopropyl hybrid silica phase exhibited higher binding capacity for most of the target drugs. The developed method afforded adequate linearity at concentrations ranging from the lower limit of quantification (0.05-1.00 ng mL(-1)) to the upper limit of quantification (40-10,500 ng mL(-1)); the coefficients of determination (r(2)) were higher than 0.9955. The precision of the method presented coefficients of variation (CV) lower than 14%; the relative standard error (RSE) of the accuracy ranged from -12% to 14%. The developed method allowed for simultaneous analysis of five antipsychotics (olanzapine, quetiapine, clozapine, haloperidol, and chlorpromazine) in combination with seven antidepressants (mirtazapine, paroxetine, citalopram, sertraline, imipramine, clomipramine, fluoxetine), two anticonvulsants (carbamazepine and lamotrigine), and two anxiolytics (diazepam and clonazepam) in plasma samples from schizophrenic patients, which should be valuable for therapeutic drug monitoring purposes. Copyright © 2015 Elsevier B.V. All rights reserved.

Speciation of As(III) and As(V) in water samples by graphite furnace atomic absorption spectrometry after solid phase extraction combined with dispersive liquid-liquid microextraction based on the solidification of floating organic drop.

PubMed

Shamsipur, Mojtaba; Fattahi, Nazir; Assadi, Yaghoub; Sadeghi, Marzieh; Sharafi, Kiomars

2014-12-01

A solid phase extraction (SPE) coupled with dispersive liquid-liquid microextraction based on the solidification of floating organic drop (DLLME-SFO) method, using diethyldithiphosphate (DDTP) as a proper chelating agent, has been developed as an ultra preconcentration technique for the determination of inorganic arsenic in water samples prior to graphite furnace atomic absorption spectrometry (GFAAS). Variables affecting the performance of both steps were thoroughly investigated. Under optimized conditions, 100mL of As(ΙΙΙ) solution was first concentrated using a solid phase sorbent. The extract was collected in 2.0 mL of acetone and 60.0 µL of 1-undecanol was added into the collecting solvent. The mixture was then injected rapidly into 5.0 mL of pure water for further DLLME-SFO. Total inorganic As(III, V) was extracted similarly after reduction of As(V) to As(III) with potassium iodide and sodium thiosulfate and As(V) concentration was calculated by difference. A mixture of Pd(NO3)2 and Mg(NO3)2 was used as a chemical modifier in GFAAS. The analytical characteristics of the method were determined. The calibration graph was linear in the rage of 10-100 ng L(-1) with detection limit of 2.5 ng L(-1). Repeatability (intra-day) and reproducibility (inter-day) of method based on seven replicate measurements of 80 ng L(-1) of As(ΙΙΙ) were 6.8% and 7.5%, respectively. The method was successfully applied to speciation of As(III), As(V) and determination of the total amount of As in water samples and in a certified reference material (NIST RSM 1643e). Copyright © 2014 Elsevier B.V. All rights reserved.

Analysis of fatty acid ethyl esters in hair as possible markers of chronically elevated alcohol consumption by headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS).

PubMed

Pragst, F; Auwaerter, V; Sporkert, F; Spiegel, K

2001-09-15

Fatty acid ethyl esters (FAEE) are products of the nonoxidative ethanol metabolism, which are known to be detectable in blood only about 24h after the last alcohol intake. After deposition in hair they should be suitable long-term markers of chronically elevated alcohol consumption. Therefore, a method for the analysis of ethyl myristate, ethyl palmitate, ethyl oleate and ethyl stearate from hair was developed based on the extraction of the hair sample by a dimethylsulphoxide (DMSO)/n-hexane mixture, separation and evaporation of the n-hexane phase and application of headspace solid-phase microextraction (HS-SPME) in combination with gas chromatography-mass spectrometry (GC-MS) to the extract. For use as internal standards, the corresponding D(5)-ethyl esters were prepared. The HS-SPME/GC-MS measurements were automatically performed using a multi-purpose sampler. The detection limits of the FAEE were between 0.01 and 0.04ng/mg and the reproducibility was between 3.5 and 16%. By application of the method to hair samples of 21 fatalities with known heavy alcohol abuse 0.045-2.4ng/mg ethyl myristate, 0.35-13.5ng/mg ethyl palmitate, 0.25-7.7ng/mg ethyl oleate and 0.05-3.85ng/mg ethyl stearate were measured. For social drinkers (30-60g ethanol per week), the concentrations were about one order of magnitude smaller. For 10 teetotalers negative results or traces of ethyl palmitate were found. It was shown by supplementary investigations in single cases that FAEE are also present in sebum, that there is no strong difference in their concentrations between pubic, chest and scalp hair, and that they are detectable in hair segments after a 2 months period of abstinence. From the results follows that the measurement of FAEE concentrations in hair is a useful way for a retrospective detection of alcohol abuse.

Ligandless surfactant mediated solid phase extraction combined with Fe₃O₄ nano-particle for the preconcentration and determination of cadmium and lead in water and soil samples followed by flame atomic absorption spectrometry: multivariate strategy.

PubMed

Jalbani, N; Soylak, M

2014-04-01

In the present study, a microextraction technique combining Fe3O4 nano-particle with surfactant mediated solid phase extraction ((SM-SPE)) was successfully developed for the preconcentration/separation of Cd(II) and Pb(II) in water and soil samples. The analytes were determined by flame atomic absorption spectrometry (FAAS). The effective variables such as the amount of adsorbent (NPs), the pH, concentration of non-ionic (TX-114) and centrifugation time (min) were investigated by Plackett-Burman (PBD) design. The important variables were further optimized by central composite design (CCD). Under the optimized conditions, the detection limits (LODs) of Cd(II) and Pb(II) were 0.15 and 0.74 µg/L, respectively. The validation of the proposed procedure was checked by the analysis of certified reference materials of TMDA 53.3 fortified water and GBW07425 soil. The method was successfully applied for the determination of Cd(II) and Pb(II) in water and soil samples. Copyright © 2014 Elsevier Inc. All rights reserved.

Determination of benzo[a]pyrene in edible oils using phase-transfer-catalyst-assisted saponification and supramolecular solvent microextraction coupled to HPLC with fluorescence detection.

PubMed

Wang, Jin; Liu, Laping; Shi, Ludi; Yi, Tingquan; Wen, Yuxia; Wang, Juanli; Liu, Shuhui

2017-01-01

For the analysis of edible oils, saponification is well known as a useful method for eliminating oil matrices. The conventional approach is conducted with alcoholic alkali; it consumes a large volume of organic solvents and impedes the retrieval of analytes by microextraction. In this study, a low-organic-solvent-consuming method has been developed for the analysis of benzo[a]pyrene in edible oils by high-performance liquid chromatography with fluorescence detection. Sample treatment involves aqueous alkaline saponification, assisted by a phase-transfer catalyst, and selective in situ extraction of the analyte with a supramolecular solvent. Comparison of the chromatograms of the oil extracts obtained by different microextraction methods showed that the supramolecular solvent has a better clean-up effect for the unsaponifiable matter from oil matrices. The method offered excellent linearity over a range of 0.03- 5.0 ng mL -1 (r > 0.999). Recovery rates varied from 94 to 102% (RSDs <5.0%). The detection limit and quantification limit were 0.06 and 0.19 μg kg -1 , respectively. The proposed method was applied for the analysis of 52 edible oils collected online in China; the analyte contents of 23 tested oil samples exceeded the maximum limit of 2 μg kg -1 for benzo[a]pyrene set by the Commission Regulation of the European Union. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multivariate optimization of a headspace solid-phase microextraction method followed by gas chromatography with mass spectrometry for the determination of terpenes in Nicotiana langsdorffii.

PubMed

Ardini, Francisco; Carro, Marina Di; Abelmoschi, Maria Luisa; Grotti, Marco; Magi, Emanuele

2014-07-01

A simple and sensitive procedure based on headspace solid-phase microextraction and gas chromatography with mass spectrometry was developed for the determination of five terpenes (α-pinene, limonene, linalool, α-terpineol, and geraniol) in the leaves of Nicotiana langsdorffii. The microextraction conditions (extraction temperature, equilibration time, and extraction time) were optimized by means of a Doehlert design. The experimental design showed that, for α-pinene and limonene, a low temperature and a long extraction time were needed for optimal extraction, while linalool, α-terpineol, and geraniol required a high temperature and a long extraction time. The chosen compromise conditions were temperature 60°C, equilibration time 15 min and extraction time 50 min. The main analytical figures of the optimized method were evaluated; LODs ranged from 0.07 ng/g (α-pinene) to 8.0 ng/g (geraniol), while intraday and interday repeatability were in the range 10-17% and 9-13%, respectively. Finally, the procedure was applied to in vitro wild-type and transgenic specimens of N. langsdorffii subjected to abiotic stresses (chemical and heat stress). With the exception of geraniol (75-374 ng/g), low concentration levels of terpenes were measured (ng/g level or lower); some interesting variations in terpene concentration induced by abiotic stress were observed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous speciation and preconcentration of ultra traces of inorganic tellurium and selenium in environmental samples by hollow fiber liquid phase microextraction prior to electrothermal atomic absorption spectroscopy determination.

PubMed

Ghasemi, Ensieh; Najafi, Nahid Mashkouri; Raofie, Farhad; Ghassempour, Alireza

2010-09-15

A simple and effective speciation and preconcentration method based on hollow fiber liquid phase microextraction (HF-LPME) was developed for simultaneous separation of trace inorganic tellurium and selenium in environmental samples prior to electrothermal atomic absorption spectroscopy (ETAAS) determination. The method involves the selective extraction of the Te (IV) and Se (IV) species by HF-LPME with the use of ammonium pyrrolidinecarbodithioate (APDC) as the chelating agent. The complex compounds were extracted into 10 microL of toluene and the solutions were injected into a graphite furnace for the determination of Te (IV) and Se (IV). To determine the total tellurium and selenium in the samples, first Te (VI) and Se (VI) were reduced to Te (IV) and Se (IV), and then the microextraction method was performed. The experimental parameters of HF-LPME were optimized using a central composite design after a 2(n-1) fractional factorial experimental design. Under optimum conditions, enrichment factors of up to 520 and 480 were achieved for Te (IV) and Se (IV), respectively. The detection limits were 4 ng L(-1) with 3.5% RSD (n=5, c=2.0 microg L(-1)) for Te (IV) and 5 ng L(-1) with 3.1% RSD for Se (IV). The applicability of the developed technique was evaluated by application to spiked, environmental water and soil samples. Copyright 2010 Elsevier B.V. All rights reserved.

Polymeric ionic liquid-based portable tip microextraction device for on-site sample preparation of water samples.

PubMed

Chen, Lei; Pei, Junxian; Huang, Xiaojia; Lu, Min

2018-06-05

On-site sample preparation is highly desired because it avoids the transportation of large-volume samples and ensures the accuracy of the analytical results. In this work, a portable prototype of tip microextraction device (TMD) was designed and developed for on-site sample pretreatment. The assembly procedure of TMD is quite simple. Firstly, polymeric ionic liquid (PIL)-based adsorbent was in-situ prepared in a pipette tip. After that, the tip was connected with a syringe which was driven by a bidirectional motor. The flow rates in adsorption and desorption steps were controlled accurately by the motor. To evaluate the practicability of the developed device, the TMD was used to on-site sample preparation of waters and combined with high-performance liquid chromatography with diode array detection to measure trace estrogens in water samples. Under the most favorable conditions, the limits of detection (LODs, S/N = 3) for the target analytes were in the range of 4.9-22 ng/L, with good coefficients of determination. Confirmatory study well evidences that the extraction performance of TMD is comparable to that of the traditional laboratory solid-phase extraction process, but the proposed TMD is more simple and convenient. At the same time, the TMD avoids complicated sampling and transferring steps of large-volume water samples. Copyright © 2018 Elsevier B.V. All rights reserved.

Preparation of 2,4-dichlorophenoxyacetic acid imprinted organic-inorganic hybrid monolithic column and application to selective solid-phase microextraction.

PubMed

Liu, Xiaofang; Zhu, Quanfei; Chen, Huaixia; Zhou, Liuzi; Dang, Xueping; Huang, Jianlin

2014-03-01

An organic-inorganic hybrid molecular imprinting monolith (HMIM) has been prepared, characterized and applied for the determination of 2,4-dichlorophenoxyacetic acid (2,4-D) in rice with high-performance liquid chromatography-photodiodes array detector (HPLC-PAD). By optimizing the polymerization conditions, such as the volume ratio of the inorganic alcoholysate and organic part, the 2,4-D-HMIM was synthesized in a micro pipette tip using acrylamide as the functional monomer, ethylene dimethacrylate as the cross-linker and methanol as the porogenic solvent. The morphology of the monolith was studied by scanning electronmicroscopy and Fourier transform infrared spectra. The imprinted factor of the monolith for 2,4-D reached 3.29. A simple, rapid and sensitive method for the determination of 2,4-D in rice using the HMIM microextraction combined with high-performance liquid chromatography-photodiodes array detector was developed. Some parameters affecting the sample pretreatment were investigated, including the type and volume of eluent, the flow rate and volume of sample solution. The assay exhibited a linear dynamic range of 167-4167μg/kg with the correlation coefficient above 0.9972. The detection limit (at S/N=3) was 50μg/kg. The proposed method was successfully applied for the selective determination of 2,4-D in rice. Copyright © 2014 Elsevier B.V. All rights reserved.

Estimation of the toxicity of sulfadiazine to Daphnia magna using negligible depletion hollow-fiber liquid-phase microextraction independent of ambient pH

NASA Astrophysics Data System (ADS)

Liu, Kailin; Xu, Shiji; Zhang, Minghuan; Kou, Yahong; Zhou, Xiaomao; Luo, Kun; Hu, Lifeng; Liu, Xiangying; Liu, Min; Bai, Lianyang

2016-12-01

The toxicity of ionizable organic compounds to organisms depends on the pH, which therefore affects risk assessments of these compounds. However, there is not a direct chemical method to predict the toxicity of ionizable organic compounds. To determine whether hollow-fiber liquid-phase microextraction (HF-LPME) is applicable for this purpose, a three-phase HF-LPME was used to measure sulfadiazine and estimate its toxicity to Daphnia magna in solutions of different pH. The result indicated that the sulfadiazine concentrations measured by HF-LPME decreased with increasing pH, which is consistent with the decreased toxicity. The concentration immobilize 50% of the daphnids (EC50) in 48 h calculated from nominal concentrations increased from 11.93 to 273.5 mg L-1 as the pH increased from 6.0 to 8.5, and the coefficient of variation (CV) of the EC50 values reached 104.6%. When calculated from the concentrations measured by HF-LPME (pH 12 acceptor phase), the EC50 ranged from 223.4 to 394.6 mg L-1, and the CV decreased to 27.60%, suggesting that the concentrations measured by HF-LPME can be used to estimate the toxicity of sulfadiazine irrespective of the solution pH.

Simultaneous determination of ochratoxin A and cyclopiazonic, mycophenolic, and tenuazonic acids in cornflakes by solid-phase microextraction coupled to high-performance liquid chromatography.

PubMed

Aresta, Antonella; Cioffi, Nicola; Palmisano, Francesco; Zambonin, Carlo G

2003-08-27

A solid-phase microextraction (SPME) method, coupled to liquid chromatography with diode array UV detection (LC-UV/DAD), for the simultaneous determination of cyclopiazonic acid, mycophenolic acid, tenuazonic acid, and ochratoxin A is described. Chromatographic separation was achieved on a propylamino-bonded silica gel stationary phase using acetonitrile/methanol/ammonium acetate buffer mixture (78:2:20, v/v/v) as mobile phase. SPME adsorption and desorption conditions were optimized using a silica fiber coated with a 60 microm thick polydimethylsiloxane/divinylbenzene film. Estimated limits of detection and limits of quantitation ranged from 3 to 12 ng/mL and from 7 to 29 ng/mL, respectively. The method has been applied to cornflake samples. Samples were subjected to a preliminary short sonication in MeOH/2% KHCO(3) (70:30, v/v); the mixture was evaporated to near dryness and reconstituted in 1.5 mL of 5 mM phosphate buffer (pH 3) for SPME followed by LC-UV/DAD. The overall procedure had recoveries (evaluated on samples spiked at 200 ng/g level) ranging from 74 +/- 4 to 103 +/- 9%. Samples naturally contaminated with cyclopiazonic and tenuazonic acids were found; estimated concentrations were 72 +/- 9 and 25 +/- 6 ng/g, respectively.

Identification of unwanted photoproducts of cosmetic preservatives in personal care products under ultraviolet-light using solid-phase microextraction and micro-matrix solid-phase dispersion.

PubMed

Alvarez-Rivera, Gerardo; Llompart, Maria; Garcia-Jares, Carmen; Lores, Marta

2015-04-17

The photochemical transformation of widely used cosmetic preservatives including benzoates, parabens, BHA, BHT and triclosan has been investigated in this work applying an innovative double-approach strategy: identification of transformation products in aqueous photodegradation experiments (UV-light, 254nm), followed by targeted screening analysis of such photoproducts in UV-irradiated cosmetic samples. Solid-phase microextraction (SPME) was applied, using different fiber coatings, in order to widen the range of detectable photoproducts in water, whereas UV-irradiated personal care products (PCPs) containing the target preservatives were extracted by micro-matrix solid-phase dispersion (micro-MSPD). Both SPME and micro-MSPD-based methodologies were successfully optimized and validated. Degradation kinetics of parent species, and photoformation of their transformation by-products were monitored by gas chromatography coupled to mass spectrometry (GC-MS). Thirty nine photoproducts were detected in aqueous photodegradation experiments, being tentatively identified based on their mass spectra. Transformation pathways between structurally related by-products, consistent with their kinetic behavior were postulated. The photoformation of unexpected photoproducts such as 2- and 4-hydroxybenzophenones, and 2,8-dichlorodibenzo-p-dioxin in PCPs are reported in this work for the first time. Copyright © 2015 Elsevier B.V. All rights reserved.

Analysis of tricyclic antidepressant drugs in plasma by means of solid-phase microextraction-liquid chromatography-mass spectrometry.

PubMed

Alves, Claudete; Santos-Neto, Alvaro J; Fernandes, Christian; Rodrigues, José C; Lanças, Fernando M

2007-10-01

Solid-phase microextraction coupled to liquid chromatography and mass spectrometry (SPME-LC-MS) was used to analyze tricyclic antidepressant drugs desipramine, imipramine, nortriptyline, amitriptyline, and clomipramine (internal standard) in plasma samples. SPME was performed by direct extraction on a PDMS/DVB (60 microm) coated fiber, employing a stirring rate of 1200 rpm for 30 min, pH 11.0, and temperature of 30 degrees C. Drug desorption was carried out by exposing the fiber to the liquid chromatography mobile phase for 20 min, using a labmade SPME-LC interface at 50 degrees C. The main variables experimentally influencing LC-MS response were evaluated and mathematically modeled. A rational optimization with fewer experiments was achieved using a factorial design approach. The constructed empirical models were adjusted with 96-98% of explained deviation allowing an adequate data set comprehension. The chromatographic separation was realized using an RP-18 column (150 mm x 2.1 mm, 5 microm particles) and ammonium acetate buffer (0.01 mol/l, pH 5.50) : acetonitrile (50 : 50 v/v) as mobile phase. Low detection levels were achieved with electrospray interface (0.1 ng/ml). The developed method showed specificity, linearity, precision, and limit of quantification adequate to assay tricyclic antidepressant drugs in plasma.

Influence of maturity and ripening on aroma volatiles and flavor in avocado

USDA-ARS?s Scientific Manuscript database

Changes in aroma volatiles were determined using solid phase microextraction (SPME) and gas chromatography in ripe avocados (Persea americana Mill.) throughout an eight-month maturation period and related to the sensory properties of the fruit. As maturation progressed sensory panelists found the li...

Comparison of methods for determining volatile compounds in cheese, milk, and whey powder

USDA-ARS?s Scientific Manuscript database

Solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) are commonly used for qualitative and quantitative analysis of volatile compounds in various dairy products, but selecting the proper procedures presents challenges. Heat is applied to drive volatiles from the samp...

Abiotic Reductive Dechlorination of Tetrachloroethylene and Trichloroethylene in Anaerobic Environments

DTIC Science & Technology

2009-01-15

Measurement of Henry’s Law Constant for methyl tert-butyl ether Using Solid-phase Microextraction. Environmental Toxicology and Chemistry 2001, 20, 1625...and Environmental Microbiology 2005, 71, 3413-3419. Nirmalakhandan, N. N., R. E. Speece. QSAR Model for Predicting Henry’s Constant. Environmental

POLY(DIMETHYLSILOXANE) FILMS AS SORBENTS FOR SOLID PHASE MICROEXTRACTION COUPLED WITH INFRARED SPECTROSCOPY. (R825343)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Headspace Volatiles of Scutellaria Baicalensis Georgi Flowers

USDA-ARS?s Scientific Manuscript database

Volatile constituents of Baikal skullcap (Scutellaria baicalensis Georgi) flowers were isolated by solid-phase microextraction (SPME) and analyzed by GC and GC/MS. A total of 64 constituents was identified (constituting 57.1 – 89.9% of the total area), 13 of which were tentatively identified. beta...

Dispersive solid-phase microextraction and capillary electrophoresis separation of food colorants in beverages using diamino moiety functionalized silica nanoparticles as both extractant and pseudostationary phase.

PubMed

Liu, Feng-Jie; Liu, Chuan-Ting; Li, Wei; Tang, An-Na

2015-01-01

In this work, a new method for the determination of food colorants in beverage samples is developed, using diamino moiety functionalized silica nanoparticles (dASNPs) as both adsorbents in dispersive solid-phase microextraction (dSPME) and pseudostationary phases (PSPs) in capillary electrophoresis (CE) separation. dASNPs were firstly used as adsorbents for the preconcentration of four colorants by the dSPME process. After that, colorants were efficiently separated by CE using 30 mM phosphate buffer (pH 6.0) containing 2 mM β-CD and 0.9 mg/mL dASNPs as additives. All factors influencing dSPME and CE separations were optimized in detail. The investigated analytes showed good linearities with correlation coefficients (R(2)) higher than 0.9932. The limits of detection for the four food colorants were between 0.030 and 0.36 mg/L, which are lower than those reported previously. The established method was also used to analyze four colorants in beverage samples with recoveries ranging from 82.7% to 114.6%. To the best of our knowledge, this is the first time to use NPs both as extractants in dSPME and pseudostationary phases in CE for the analytical purpose. Copyright © 2014 Elsevier B.V. All rights reserved.

Silica- and germania-based dual-ligand sol-gel organic-inorganic hybrid sorbents combining superhydrophobicity and π-π interaction. The role of inorganic substrate in sol-gel capillary microextraction.

PubMed

Seyyal, Emre; Malik, Abdul

2017-04-29

Principles of sol-gel chemistry were utilized to create silica- and germania-based dual-ligand surface-bonded sol-gel coatings providing enhanced performance in capillary microextraction (CME) through a combination of ligand superhydrophobicity and π-π interaction. These organic-inorganic hybrid coatings were prepared using sol-gel precursors with bonded perfluorododecyl (PF-C 12 ) and phenethyl (PhE) ligands. Here, the ability of the PF-C 12 ligand to provide enhanced hydrophobic interaction was advantageously combined with π-π interaction capability of the PhE moiety to attain the desired sorbent performance in CME. The effect of the inorganic sorbent component on microextraction performance of was explored by comparing microextraction characteristics of silica- and germania-based sol-gel sorbents. The germania-based dual-ligand sol-gel sorbent demonstrated superior CME performance compared to its silica-based counterpart. Thermogravimetric analysis (TGA) of the created silica- and germania-based dual-ligand sol-gel sorbents suggested higher carbon loading on the germania-based sorbent. This might be indicative of more effective condensation of the organic ligand-bearing sol-gel-active chemical species to the germania-based sol-gel network (than to its silica-based counterpart) evolving in the sol solution. The type and concentration of the organic ligands were varied in the sol-gel sorbents to fine-tune extraction selectivity toward different classes of analytes. Specific extraction (SE) values were used for an objective comparison of the prepared sol-gel CME sorbents. The sorbents with higher content of PF-C 12 showed remarkable affinity for aliphatic hydrocarbons. Compared to their single-ligand sol-gel counterparts, the dual-ligand sol-gel coatings demonstrated significantly superior CME performance in the extraction of alkylbenzenes, providing up to ∼65.0% higher SE values. The prepared sol-gel CME coatings provided low ng L -1 limit of detections (LOD) (4.2-26.3 ng L -1 ) for environmentally important analytes including polycyclic aromatic hydrocarbons, ketones and aliphatic hydrocarbons. In CME-GC experiments (n = 5), the capillary-to-capillary RSD value was ∼2.1%; such a low RSD value is indicative of excellent reproducibility of the sol-gel method used for the preparation of these CME coatings. The dual-ligand sol-gel coating provided stable performance in capillary microextraction of analytes from saline samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Validation and Determination of the Contents of Acetaldehyde and Formaldehyde in Foods

PubMed Central

Jeong, Hye-Seung; Chung, Hyun; Song, Sang-Hoon; Kim, Cho-Il; Lee, Joon-Goo

2015-01-01

The aim of this study was to develop an efficient quantitative method for the determination of acetaldehyde (AA) and formaldehyde (FA) contents in solid and liquid food matrices. The determination of those compounds was validated and performed using gas chromatography-mass spectrometry combined by solid phase micro-extraction after derivatization with O-(2,3,4,5,6-pentafluoro-benzyl)-hydroxylamine hydrochloride. Validation was carried out in terms of limit of detection, limit of quantitation, linearity, precision, and recovery. Then their contents were analyzed in various food samples including 15 fruits, 22 milk products, 31 alcohol-free beverages, and 13 alcoholic beverages. The highest contents of AA and FA were determined in a white wine (40,607.02 ng/g) and an instant coffee (1,522.46 ng/g), respectively. PMID:26483886

Application of headspace and direct immersion solid-phase microextraction in the analysis of organothiophosphates related to the Chemical Weapons Convention from water and complex matrices.

PubMed

Althoff, Marc André; Bertsch, Andreas; Metzulat, Manfred; Klapötke, Thomas M; Karaghiosoff, Konstantin L

2017-11-01

The successful application of headspace (HS) and direct immersion (DI) solid phase microextraction (SPME) for the unambiguous identification and characterization of a series of toxic thiophosphate esters, such as Amiton (I), from aqueous phases and complex matrices (e.g. grass and foliage) has been demonstrated. A Thermo Scientific gas chromatograph (GC) - tandem mass spectrometer (MS/MS) system with a TriPlus RSH® autosampler and a SPME tool was used to investigate the effect of different parameters that influence the extraction efficiency: e.g. pH of the sample matrix and extraction temperature. The developed methods were employed for the detection of several Amiton derivatives (Schedule II of the CWC) that are structurally closely related to each other; some of which are new and have not been reported in literature previously. In addition, a novel DI SPME method from complex matrices for the analysis of organophosphates related to the CWC was developed. The studies clearly show that DI SPME for complex matrices is superior to HS extraction and can potentially be applied to other related compounds controlled under the CWC. Copyright © 2017. Published by Elsevier B.V.

Bis(trifluoromethylsulfonyl)imide-based frozen ionic liquid for the hollow-fiber solid-phase microextraction of dichlorodiphenyltrichloroethane and its main metabolites.

PubMed

Pang, Long; Yang, Peijie; Pang, Rong; Li, Shunyi

2017-08-01

1-Hexadecyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide is a solid-phase ionic organic material under ambient temperature and is considered as a kind of "frozen" ionic liquid. Because of their solid-state and ultra-hydrophobicity, "frozen" ionic liquids are able to be confined in the pores of hollow fiber, based on which a simple method was developed for the hollow-fiber solid-phase microextraction of dichlorodiphenyltrichloroethane and its main metabolites. Under optimized conditions, the proposed method results in good linearity (R 2 > 0.9965) over the range of 0.5-50 μg/L, with low limits of detection and quantification in the range of 0.33-0.38 and 1.00-1.25 μg/L, respectively. Intra- and interday precisions evaluated by relative standard deviation were 3-6 and 1-6%, respectively. The spiked recoveries of dichlorodiphenyltrichloroethane and its main metabolites from real water samples were in the range of 64-113 and 79-112%, respectively, at two different concentration levels. The results suggest that "frozen" ionic liquids are promising for use as a class of novel sorbents. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solid-phase microextraction for qualitative and quantitative determination of migrated degradation products of antioxidants in an organic aqueous solution.

PubMed

Burman, Lina; Albertsson, Ann-Christine; Höglund, Anders

2005-07-08

Low molecular weight aromatic substances may migrate out from plastic packaging to their contents, especially if they consist of organic aqueous solutions or oils. It is, therefore, extremely important to be able to identify and quantify any migrated substances in such solutions, even at very low concentrations. We have in this work investigated and evaluated the use of solid-phase microextraction for the specific task of extraction from an organic aqueous solution such as a simulated pharmaceutical solution consisting of 10 vol.% ethanol in water. The goal was furthermore to investigate the possibility of simultaneously identifying and quantifying the substances in spite of differences in their chemical structures. Methods were developed and evaluated for extraction both with direct sampling and with headspace sampling. Difficulties appeared due to the ethanol in the solution and the minute amounts of substances present. We have shown that a simultaneous quantification of migrated low molecular weight degradation products of antioxidants using only one fibre is possible if the extraction method and temperature are adjusted in relation to the concentration levels of the analytes. Comparions were made with solid-phase extraction.

Method optimization for non-equilibrium solid phase microextraction sampling of HAPs for GC/MS analysis

NASA Astrophysics Data System (ADS)

Zawadowicz, M. A.; Del Negro, L. A.

2010-12-01

Hazardous air pollutants (HAPs) are usually present in the atmosphere at pptv-level, requiring measurements with high sensitivity and minimal contamination. Commonly used evacuated canister methods require an overhead in space, money and time that often is prohibitive to primarily-undergraduate institutions. This study optimized an analytical method based on solid-phase microextraction (SPME) of ambient gaseous matrix, which is a cost-effective technique of selective VOC extraction, accessible to an unskilled undergraduate. Several approaches to SPME extraction and sample analysis were characterized and several extraction parameters optimized. Extraction time, temperature and laminar air flow velocity around the fiber were optimized to give highest signal and efficiency. Direct, dynamic extraction of benzene from a moving air stream produced better precision (±10%) than sampling of stagnant air collected in a polymeric bag (±24%). Using a low-polarity chromatographic column in place of a standard (5%-Phenyl)-methylpolysiloxane phase decreased the benzene detection limit from 2 ppbv to 100 pptv. The developed method is simple and fast, requiring 15-20 minutes per extraction and analysis. It will be field-validated and used as a field laboratory component of various undergraduate Chemistry and Environmental Studies courses.

Application of solid phase microextraction followed by liquid chromatography-mass spectrometry in the determination of antibiotic drugs and their metabolites in human whole blood and tissue samples.

PubMed

Szultka-Mlynska, Malgorzata; Pomastowski, Pawel; Buszewski, Boguslaw

2018-06-01

A sensitive, rapid and specific analytical method using high performance liquid chromatography coupled with mass spectrometry (HPLC-QqQ-MS) was developed to determine selected antibiotic drugs and their metabolites (amoxicillin, cefotaxime, ciprofloxacin, clindamycin and metronidazole; amoxycilloic acid, 4-hydroxyphenyl glycyl amoxicillin, desacetyl cefotaxime, 3-desacetyl cefotaxime lactone, ciprofloxacin N-oxide, N-demethylclindamycin, clindamycin sulfoxide, and hydroxy metronidazole) in human whole blood and vascularized tissue after single oral administration. The samples were prepared by solid phase microextraction with C18 fibers (SPME C18 ) and determined on a GRACE analytical C18 column, Vision HT (50 × 2 mm, 1.5 μm) at the flow rate of 0.4 mL min -1 using water and acetonitrile (containing 0.1% formic acid) as the mobile phase. The proposed method was successfully applied in a pharmacokinetic study of the selected antibiotic drugs and their metabolites in real human samples. Additionally, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI/TOF-MS) was used for identification and qualification analysis of the target compounds. Copyright © 2018 Elsevier B.V. All rights reserved.

Headspace solid-phase microextraction and gas chromatographic analysis of low-molecular-weight sulfur volatiles with pulsed flame photometric detection and quantification by a stable isotope dilution assay.

PubMed

Ullrich, Sebastian; Neef, Sylvia K; Schmarr, Hans-Georg

2018-02-01

Low-molecular-weight volatile sulfur compounds such as thiols, sulfides, disulfides as well as thioacetates cause a sulfidic off-flavor in wines even at low concentration levels. The proposed analytical method for quantification of these compounds in wine is based on headspace solid-phase microextraction, followed by gas chromatographic analysis with sulfur-specific detection using a pulsed flame photometric detector. Robust quantification was achieved via a stable isotope dilution assay using commercial and synthesized deuterated isotopic standards. The necessary chromatographic separation of analytes and isotopic standards benefits from the inverse isotope effect realized on an apolar polydimethylsiloxane stationary phase of increased film thickness. Interferences with sulfur-specific detection in wine caused by sulfur dioxide were minimized by addition of propanal. The method provides adequate validation data, with good repeatability and limits of detection and quantification. It suits the requirements of wine quality management, allowing the control of oenological treatments to counteract an eventual formation of excessively high concentration of such malodorous compounds. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ultrasound assisted extraction combined with dispersive liquid-liquid microextraction (US-DLLME)-a fast new approach to measure phthalate metabolites in nails.

PubMed

Alves, Andreia; Vanermen, Guido; Covaci, Adrian; Voorspoels, Stefan

2016-09-01

A new, fast, and environmentally friendly method based on ultrasound assisted extraction combined with dispersive liquid-liquid microextraction (US-DLLME) was developed and optimized for assessing the levels of seven phthalate metabolites (including the mono(ethyl hexyl) phthalate (MEHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (5-OH-MEHP), mono(2-ethyl-5-oxohexyl) phthalate (5-oxo-MEHP), mono-n-butyl phthalate (MnBP), mono-isobutyl phthalate (MiBP), monoethyl phthalate (MEP), and mono-benzyl phthalate (MBzP)) in human nails by UPLC-MS/MS. The optimization of the US-DLLME method was performed using a Taguchi combinatorial design (L9 array). Several parameters such as extraction solvent, solvent volume, extraction time, acid, acid concentration, and vortex time were studied. The optimal extraction conditions achieved were 180 μL of trichloroethylene (extraction solvent), 2 mL trifluoroacetic acid in methanol (2 M), 2 h extraction and 3 min vortex time. The optimized method had a good precision (6-17 %). The accuracy ranged from 79 to 108 % and the limit of method quantification (LOQm) was below 14 ng/g for all compounds. The developed US-DLLME method was applied to determine the target metabolites in 10 Belgian individuals. Levels of the analytes measured in nails ranged between <12 and 7982 ng/g. The MEHP, MBP isomers, and MEP were the major metabolites and detected in every sample. Miniaturization (low volumes of organic solvents used), low costs, speed, and simplicity are the main advantages of this US-DLLME based method. Graphical Abstract Extraction and phase separation of the US-DLLME procedure.

Determination of octylphenol and nonylphenol in aqueous sample using simultaneous derivatization and dispersive liquid-liquid microextraction followed by gas chromatography-mass spectrometry.

PubMed

Luo, Shusheng; Fang, Ling; Wang, Xiaowei; Liu, Hongtao; Ouyang, Gangfeng; Lan, Chongyu; Luan, Tiangang

2010-10-22

A simple and fast sample preparation method for the determination of nonylphenol (NP) and octylphenol (OP) in aqueous samples by simultaneous derivatization and dispersive liquid-liquid microextraction (DLLME) was investigated using gas chromatography-mass spectrometry (GC/MS). In this method, a combined dispersant/derivatization catalyst (methanol/pyridine mixture) was firstly added to an aqueous sample, following which a derivatization reagent/extraction solvent (methyl chloroformate/chloroform) was rapidly injected to combine in situ derivatization and extraction in a single step. After centrifuging, the sedimented phase containing the analytes was injected into the GC port by autosampler for analysis. Several parameters, such as extraction solvent, dispersant solvent, amount of derivatization reagent, derivatization and extraction time, pH, and ionic strength were optimized to obtain higher sensitivity for the detection of NP and OP. Under the optimized conditions, good linearity was observed in the range of 0.1-1000 μg L⁻¹ and 0.01-100 μg L⁻¹ with the limits of detection (LOD) of 0.03 μg L⁻¹ and 0.002 μg L⁻¹ for NP and OP, respectively. Water samples collected from the Pearl River were analyzed with the proposed method, the concentrations of NP and OP were found to be 2.40 ± 0.16 μg L⁻¹ and 0.037 ± 0.001 μg L⁻¹, respectively. The relative recoveries of the water samples spiked with different concentrations of NP and OP were in the range of 88.3-106.7%. Compared with SPME and SPE, the proposed method can be successfully applied to the rapid and convenient determination of NP and OP in aqueous samples. Copyright © 2010 Elsevier B.V. All rights reserved.

Sensitive determination of methadone in human serum and urine by dispersive liquid-liquid microextraction based on the solidification of a floating organic droplet followed by HPLC-UV.

PubMed

Taheri, Salman; Jalali, Fahimeh; Fattahi, Nazir; Jalili, Ronak; Bahrami, Gholamreza

2015-10-01

Dispersive liquid-liquid microextraction based on solidification of floating organic droplet was developed for the extraction of methadone and determination by high-performance liquid chromatography with UV detection. In this method, no microsyringe or fiber is required to support the organic microdrop due to the usage of an organic solvent with a low density and appropriate melting point. Furthermore, the extractant droplet can be collected easily by solidifying it at low temperature. 1-Undecanol and methanol were chosen as extraction and disperser solvents, respectively. Parameters that influence extraction efficiency, i.e. volumes of extracting and dispersing solvents, pH, and salt effect, were optimized by using response surface methodology. Under optimal conditions, enrichment factor for methadone was 134 and 160 in serum and urine samples, respectively. The limit of detection was 3.34 ng/mmL in serum and 1.67 ng/mL in urine samples. Compared with the traditional dispersive liquid-liquid microextraction, the proposed method obtained lower limit of detection. Moreover, the solidification of floating organic solvent facilitated the phase transfer. And most importantly, it avoided using high-density and toxic solvents of traditional dispersive liquid-liquid microextraction method. The proposed method was successfully applied to the determination of methadone in serum and urine samples of an addicted individual under methadone therapy. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dispersive liquid-liquid microextraction for the determination of vitamins D and K in foods by liquid chromatography with diode-array and atmospheric pressure chemical ionization-mass spectrometry detection.

PubMed

Viñas, Pilar; Bravo-Bravo, María; López-García, Ignacio; Hernández-Córdoba, Manuel

2013-10-15

A simple and rapid method was developed using reversed-phase liquid chromatography (LC) with both diode array (DAD) and atmospheric pressure chemical ionization mass spectrometric (APCI-MS) detection, for the simultaneous analysis of the vitamins ergocalciferol (D2), cholecalciferol (D3), phylloquinone (K1), menaquinone-4 (K2) and a synthetic form of vitamin K, menadione (K3). The Taguchi experimental method, an orthogonal array design (OAD), was used to optimize an efficient and clean preconcentration step based on dispersive liquid-liquid microextraction (DLLME). A factorial design was applied with six factors and three levels for each factor, namely, carbon tetrachloride volume, methanol volume, aqueous sample volume, pH of sample, sodium chloride concentration and time of the centrifugation step. The DLLME optimized procedure consisted of rapidly injecting 3 mL of acetonitrile (disperser solvent) containing 150 µL carbon tetrachloride (extraction solvent) into the aqueous sample, thereby forming a cloudy solution. Phase separation was performed by centrifugation, and the sedimented phase was evaporated with nitrogen, reconstituted with 50 µL of acetonitrile, and injected. The LC analyses were carried out using a mobile phase composed of acetonitrile, 2-propanol and water, under gradient elution. Quantification was carried out by the standard additions method. The APCI-MS spectra, in combination with UV spectra, permitted the correct identification of compounds in the food samples. The method was validated according to international guidelines and using a certified reference material. The validated method was applied for the analysis of vitamins D and K in infant foods and several green vegetables. There was little variability in the forms of vitamin K present in vegetables, with the most abundant vitamer in all the samples being phylloquinone, while menadione could not be detected. Conversely, cholecalciferol, which is present in food of animal origin, was the main form in infant foods, while ergocalciferol was not detected. Copyright © 2013 Elsevier B.V. All rights reserved.

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 Cinnamaldehyde in Cinnamon by SPME-GC-MS: An Instrumental Analysis Experiment

ERIC Educational Resources Information Center

Wang, Yimin; Ocariz, Jessica; Hammersand, Jennifer; MacDonald, Evan; Bartczak, Ashley; Kero, Frank; Young, Vaneica Y.; Williams, Kathryn R.

2008-01-01

Students analyze "trans"-cinnamaldehyde in commercial cinnamon using solid-phase microextraction and GC-MS with ethyl benzoate as the internal standard. Aside from the instrumentation, the experiment utilizes readily available low hazard materials and can be completed within one four-hour laboratory period. (Contains 2 figures.)

Comparison of methods for determining volatile compounds in milk, cheese, and whey powder

USDA-ARS?s Scientific Manuscript database

Solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) are commonly used for qualitative and quantitative analysis of volatile compounds in various dairy products, but conditions have to be adjusted for optimal SPME release while not generating new compounds that are abs...

APPLICATION OF SOLID PHASE MICROEXTRACTION GC/MS TO THE CHARACTERIZATION OF HYDROPHILIC DISINFECTION BY-PRODUCTS IN WATER

EPA Science Inventory

The U.S. Environmental Protection Agency has given high priority to research aimed at developing methods to extract hydrophilic disinfection by-products (DBPs) from drinking water. Public water supplies are treated with a variety of chemicals aimed at reducing or eliminating inf...

Identification of volatiles from waste larval rearing media that attract gravid screwworm flies to oviposit

USDA-ARS?s Scientific Manuscript database

The waste product of the artificial larval rearing media of the primary screwworm, Cochliomyia hominivorax, attracts gravid female screwworm flies to oviposit. The volatile component of this waste product was collected using solid phase microextraction techniques and subjected to gas chromatography-...

Characterization of volatile and polar compounds of Jiaogulan Tea [Gynostemma pentaphyllum (Thunb.) Makino] by hyphenated analytical techniques

USDA-ARS?s Scientific Manuscript database

Jiaogulan [Gynostemma pentaphyllum (Thunb.) Makino] is a Chinese medical plant from southern Asia that has rapidly gained popularity and interest for its health-promotive and therapeutic properties. The volatile composition of jiaogulan tea was analyzed by using headspace-solid phase microextraction...

SOLID-PHASE MICROEXTRACTION WITH PH ADJUSTMENT FOR THE DETERMINATION OF AROMATIC ACIDS AND BASES IN WATER. (R825368)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Rapid determination of floral aroma compounds of lilac blossom by fast gas chromatography combined with surface acoustic wave sensor.

PubMed

Oh, Se Yeon; Shin, Hyun Du; Kim, Sung Jean; Hong, Jongki

2008-03-07

A novel analytical method using fast gas chromatography combined with surface acoustic wave sensor (GC/SAW) has been developed for the detection of volatile aroma compounds emanated from lilac blossom (Syringa species: Syringa vulgaris variginata and Syringa dilatata). GC/SAW could detect and quantify various fragrance emitted from lilac blossom, enabling to provide fragrance pattern analysis results. The fragrance pattern analysis could easily characterize the delicate differences in aromas caused by the substantial difference of chemical composition according to different color and shape of petals. Moreover, the method validation of GC/SAW was performed for the purpose of volatile floral actual aroma analysis, achieving a high reproducibility and excellent sensitivity. From the validation results, GC/SAW could serve as an alternative analytical technique for the analysis of volatile floral actual aroma of lilac. In addition, headspace solid-phase microextraction (HS-SPME) GC-MS was employed to further confirm the identification of fragrances emitted from lilac blossom and compared to GC/SAW.

Off-flavor related volatiles in soymilk as affected by soybean variety, grinding, and heat-processing methods.

PubMed

Zhang, Yan; Guo, Shuntang; Liu, Zhisheng; Chang, Sam K C

2012-08-01

Off-flavor of soymilk is a barrier to the acceptance of consumers. The objectionable soy odor can be reduced through inhibition of their formation or through removal after being formed. In this study, soymilk was prepared by three grinding methods (ambient, cold, and hot grinding) from two varieties (yellow Prosoy and a black soybean) before undergoing three heating processes: stove cooking, one-phase UHT (ultrahigh temperature), and two-phase UHT process using a Microthermics direct injection processor, which was equipped with a vacuuming step to remove injected water and volatiles. Eight typical soy odor compounds, generated from lipid oxidation, were extracted by a solid-phase microextraction method and analyzed by gas chromatography. The results showed that hot grinding and cold grinding significantly reduced off-flavor as compared with ambient grinding, and hot grinding achieved the best result. The UHT methods, especially the two-phase UHT method, were effective to reduce soy odor. Different odor compounds showed distinct concentration patterns because of different formation mechanisms. The two varieties behaved differently in odor formation during the soymilk-making process. Most odor compounds could be reduced to below the detection limit through a combination of hot grinding and two-phase UHT processing. However, hot grinding gave lower solid and protein recoveries in soymilk.

Optimization of ultrasound-assisted dispersive solid-phase microextraction based on nanoparticles followed by spectrophotometry for the simultaneous determination of dyes using experimental design.

PubMed

Asfaram, Arash; Ghaedi, Mehrorang; Goudarzi, Alireza

2016-09-01

A simple, low cost and ultrasensitive method for the simultaneous preconcentration and determination of trace amount of auramine-O and malachite green in aqueous media following accumulation on novel and lower toxicity nanomaterials by ultrasound-assisted dispersive solid phase micro-extraction (UA-DSPME) procedure combined with spectrophotometric has been described. The Mn doped ZnS nanoparticles loaded on activated carbon were characterized by Field emission scanning electron microscopy (FE-SEM), particle size distribution, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) analyses and subsequently were used as green and efficient material for dyes accumulation. Contribution of experimental variables such as ultrasonic time, ultrasonic temperature, adsorbent mass, vortex time, ionic strength, pH and elution volume were optimized through experimental design, and while the preconcentrated analytes were efficiently eluted by acetone. Preliminary Plackett-Burman design was applied for selection of most significant factors and giving useful information about their main and interaction part of significant variables like ultrasonic time, adsorbent mass, elution volume and pH were obtained by central composite design combined with response surface analysis and optimum experimental conditions was set at pH of 8.0, 1.2mg of adsorbent, 150μL eluent and 3.7min sonication. Under optimized conditions, the average recoveries (five replicates) for two dyes (spiked at 500.0ngmL(-1)) changes in the range of 92.80-97.70% with acceptable RSD% less than 4.0% over a linear range of 3.0-5000.0ngmL(-1) for the AO and MG in water samples with regression coefficients (R(2)) of 0.9975 and 0.9977, respectively. Acceptable limits of detection of 0.91 and 0.61ngmL(-1) for AO and MG, respectively and high accuracy and repeatability are unique advantages of present method to improve the figures of merit for their accurate determination at trace level in complicated materials. Copyright © 2016 Elsevier B.V. All rights reserved.

A solid-phase microextraction-gas chromatographic approach combined with triple quadrupole mass spectrometry for the assay of carbamate pesticides in water samples.

PubMed

Cavaliere, Brunella; Monteleone, Marcello; Naccarato, Attilio; Sindona, Giovanni; Tagarelli, Antonio

2012-09-28

A simple and sensitive method was developed for the quantification of five carbamate pesticides in water samples using solid phase microextraction (SPME) combined with gas chromatography-triple quadrupole mass spectrometry (GC-QqQ-MS). The performance of five SPME fibers was tested in univariate mode whereas the other variables affecting the efficiency of SPME analysis were optimized by the multivariate approach of design of experiment (DoE) and, in particular, a central composite design (CCD) was applied. The optimum working conditions in terms of response values were achieved by performing analysis with polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber in immersion mode for 45min at room temperature with addition of NaCl (10%). The multivariate chemometric approach was also used to explore the chromatographic behavior of the carbamates and to evaluate the importance of each variable investigated. An overall appraisement of results shows that the factor which gave a statistically significant effect on the response was only the injection temperature. Identification and quantification of carbamates was performed by using a gas chromatography-triple quadrupole mass spectrometry (GC-QqQ-MS) system in multiple reaction monitoring (MRM) acquisition. Since the choice of internal standard represented a crucial step in the development of method to achieve good reproducibility and robustness for the entire analytical protocol, three compounds (2,3,5-trimethacarb, 4-bromo-3,5-dimethylphenyl-n-methylcarbamate (BDMC) and carbaryl-d7) were evaluated as internal standards. Both precision and accuracy of the proposed protocol tested at concentration of 0.08, 5 and 3 μg l⁻¹ offered values ranging from 70.8% and 115.7% (except for carbaryl at 3 μg l⁻¹) and from 1.0% and 9.0% for accuracy and precision, respectively. Moreover, LOD and LOQ values ranging from 0.04 to 1.7 ng l⁻¹ and from 0.64 to 2.9 ng l⁻¹, respectively, can be considered very satisfactory. Copyright © 2012 Elsevier B.V. All rights reserved.

Switchable polarity solvent for liquid phase microextraction of Cd(II) as pyrrolidinedithiocarbamate chelates from environmental samples.

PubMed

Yilmaz, Erkan; Soylak, Mustafa

2015-07-30

A switchable polarity solvent was synthesized from triethylamine (TEA)/water/CO2 (Dry ice) via proton transfer reaction has been used for the microextraction of cadmium(II) as pyrrolidinedithiocarbamate (APDC) chelate. Cd(II)-APDC chelate was extracted into the switchable polarity solvent drops by adding 2 mL 10 M sodium hydroxide solution. Analytical parameters affecting the complex formation and microextraction efficiency such as pH, amount of ligand, volume of switchable polarity solvent and NaOH, sample volume were optimized. The effects of foreign ions were found tolerably. Under optimum conditions, the detection limit was 0.16 μg L(-1) (3Sb/m, n = 7) and the relative standard deviation was 5.4% (n = 7). The method was validated by the analysis of certified reference materials (TMDA-51.3 fortified water, TMDA-53.3 fortified water and SPS-WW2 waste water, 1573a Tomato Leaves and Oriental Basma Tobacco Leaves (INCT-OBTL-5)) and addition/recovery tests. The method was successfully applied to determination of cadmium contents of water, vegetable, fruit and cigarette samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Ligandless dispersive liquid--liquid microextraction of iron in biological and foodstuff samples and its determination by Electrothermal atomic absorption spectrometry.

PubMed

Madadizadeh, Mohadeseh; Taher, Mohammad Ali; Ashkenani, Hamid

2013-01-01

A new, simple, and efficient method comprising ligandless dispersive liquid-liquid microextraction combined with electrothermal atomic absorption spectrometry is reported for the preconcentration and determination of ultratrace amounts of Fe(III). Carbon tetrachloride and acetone were used as the extraction and disperser solvents, respectively. Some effective parameters of the microextraction such as choice of extraction and disperser solvents, their volume, extraction time and temperature, salt and surfactant effect, and pH were optimized. Under the optimum conditions, the calibration curve was linear in the range of 0.02 to 0.46 microg/L of Fe(III), with LOD and LOQ of 5.2 and 17.4 ng/L, respectively. The RSD for seven replicated determinations of Fe(IIl) ion at 0.1 microg/L concentration level was 5.2%. Operational simplicity, rapidity, low cost, good repeatability, and low consumption of extraction solvent are the main advantages of the proposed method. The method was successfully applied to the determination of iron in biological, food, and certified reference samples.

Comparison of two novel in-syringe dispersive liquid-liquid microextraction techniques for the determination of iodide in water samples using spectrophotometry.

PubMed

Kaykhaii, Massoud; Sargazi, Mona

2014-01-01

Two new, rapid methodologies have been developed and applied successfully for the determination of trace levels of iodide in real water samples. Both techniques are based on a combination of in-syringe dispersive liquid-liquid microextraction (IS-DLLME) and micro-volume UV-Vis spectrophotometry. In the first technique, iodide is oxidized with nitrous acid to the colorless anion of ICl2(-) at high concentration of hydrochloric acid. Rhodamine B is added and by means of one step IS-DLLME, the ion-pair formed was extracted into toluene and measured spectrophotometrically. Acetone is used as dispersive solvent. The second method is based on the IS-DLLME microextraction of iodide as iodide/1, 10-phenanthroline-iron((II)) chelate cation ion-pair (colored) into nitrobenzene. Methanol was selected as dispersive solvent. Optimal conditions for iodide extraction were determined for both approaches. Methods are compared in terms of analytical parameters such as precision, accuracy, speed and limit of detection. Both methods were successfully applied to determining iodide in tap and river water samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Ultrasound-assisted dispersive liquid-liquid microextraction based on the solidification of a floating organic droplet followed by gas chromatography for the determination of eight pyrethroid pesticides in tea samples.

PubMed

Hou, Xiaohong; Zheng, Xin; Zhang, Conglu; Ma, Xiaowei; Ling, Qiyuan; Zhao, Longshan

2014-10-15

A novel ultrasound-assisted dispersive liquid-liquid microextraction based on solidification of floating organic droplet method (UA-DLLME-SFO) combined with gas chromatography (GC) was developed for the determination of eight pyrethroid pesticides in tea for the first time. After ultrasound and centrifugation, 1-dodecanol and ethanol was used as the extraction and dispersive solvent, respectively. A series of parameters, including extraction solvent and volume, dispersive solvent and volume, extraction time, pH, and ultrasonic time influencing the microextraction efficiency were systematically investigated. Under the optimal conditions, the enrichment factors (EFs) were from 292 to 883 for the eight analytes. The linear ranges for the analytes were from 5 to 100μg/kg. The method recoveries ranged from 92.1% to 99.6%, with the corresponding RSDs less than 6.0%. The developed method was considered to be simple, fast, and precise to satisfy the requirements of the residual analysis of pyrethroid pesticides. Copyright © 2014 Elsevier B.V. All rights reserved.

A new chiral residue analysis method for triazole fungicides in water using dispersive liquid-liquid microextraction (DLLME).

PubMed

Luo, Mai; Liu, Donghui; Zhou, Zhiqiang; Wang, Peng

2013-09-01

A rapid, simple, reliable, and environment-friendly method for the residue analysis of the enantiomers of four chiral fungicides including hexaconazole, triadimefon, tebuconazole, and penconazole in water samples was developed by dispersive liquid-liquid microextraction (DLLME) pretreatment followed by chiral high-performance liquid chromatography (HPLC)-DAD detection. The enantiomers were separated on a Chiralpak IC column by HPLC applying n-hexane or petroleum ether as mobile phase and ethanol or isopropanol as modifier. The influences of mobile phase composition and temperature on the resolution were investigated and most of the enantiomers could be completely separated in 20 min under optimized conditions. The thermodynamic parameters indicated that the separation was enthalpy-driven. The elution orders were detected by both circular dichroism detector (CD) and optical rotatory dispersion detector (ORD). Parameters affecting the DLLME performance for pretreatment of the chiral fungicides residue in water samples, such as the extraction and dispersive solvents and their volume, were studied and optimized. Under the optimum microextraction condition the enrichment factors were over 121 and the linearities were 30-1500 µg L(-1) with the correlation coefficients (R(2)) over 0.9988 and the recoveries were between 88.7% and 103.7% at the spiking levels of 0.5, 0.25, and 0.05 mg L(-1) (for each enantiomer) with relative standard deviations varying from 1.38% to 6.70% (n = 6) The limits of detection (LODs) ranged from 8.5 to 29.0 µg L(-1) (S/N = 3). © 2013 Wiley Periodicals, Inc.

Dispersive liquid-liquid microextraction and preconcentration of thallium species in water samples by two ionic liquids applied as ion-pairing reagent and extractant phase.

PubMed

Escudero, Leticia B; Berton, Paula; Martinis, Estefanía M; Olsina, Roberto A; Wuilloud, Rodolfo G

2012-01-15

In the present work, a simple and highly sensitive analytical methodology for determination of Tl(+) and Tl(3+) species, based on the use of modern and non-volatile solvents, such as ionic liquids (ILs), was developed. Initially, Tl(+) was complexed by iodide ion at pH 1 in diluted sulfuric acid solution. Then, tetradecyl(trihexyl)phosphonium chloride ionic liquid (CYPHOS(®) IL 101) was used as ion-pairing reagent and a dispersive liquid-liquid microextraction (DLLME) procedure was developed by dispersing 60 mg of 1-hexyl-3-methylimidazolium hexafluorophosphate [C(6) mim][PF(6)] with 500 μL of ethanol in the aqueous solution. After the microextraction procedure was finished, the final IL phase was solubilized in methanol and directly injected into the graphite furnace of an electrothermal atomic absorption spectrometer (ETAAS). An extraction efficiency of 77% and a sensitivity enhancement factor of 100 were obtained with only 5.00 mL of sample. The limit of detection (LOD) was 3.3 ng L(-1) Tl while the relative standard deviation (RSD) was 5.3% (at 0.4 μg L(-1) Tl and n=10), calculated from the peak height of absorbance signals. The method was finally applied to determine Tl species in tap and river water samples after separation of Tl(3+) species. To the best of our knowledge, this work reports the first application of ILs for Tl extraction and separation in the analytical field. Copyright © 2011 Elsevier B.V. All rights reserved.

Ion-pair vortex assisted liquid-liquid microextraction with back extraction coupled with high performance liquid chromatography-UV for the determination of metformin in plasma.

PubMed

Alshishani, Anas; Makahleh, Ahmad; Yap, Hui Fang; Gubartallah, Elbaleeq Adam; Salhimi, Salizawati Muhamad; Saad, Bahruddin

2016-12-01

A new sample preparation method, ion-pair vortex assisted liquid-liquid microextraction (VALLME-BE), for the determination of a highly polar anti-diabetic drug (metformin) in plasma sample was developed. The VALLME-BE was performed by diluting the plasma in borate buffer and extracted to 150µL 1-octanol containing 0.2M di-(2-ethylhexyl)phosphoric acid as intermediate phase. The drug was next back-extracted into 20µL of 0.075M HCl solution. The effects of pH, ion-pair concentration, type of organic solvent, volume of extraction phases, ionic strength, vortexing and centrifugation times on the extraction efficiency were investigated. The optimum conditions were at pH 9.3, 60s vortexing and 2min centrifugation. The microextract, contained metformin and buformin (internal standard), was directly injected into a HPLC unit using C1 column (250mm×4.6mm×10µm) and detected at 235nm. The method was validated and calibration curve was linear with r 2 >0.99 over the range of 20-2000µgL -1 . The limits of detection and quantitation were 1.4 and 4.1µgL -1 , respectively. The accuracy was within 94.8-108% of the nominal concentration. The relative standard deviation for inter- and intra-day precision was less than 10.8%. The method was conveniently applied for the determination of metformin in plasma samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Identification of Chemicals Emitted by Calling Males of the Sapote Fruit Fly, Anastrepha serpentina (Diptera: Tephritidae)

USDA-ARS?s Scientific Manuscript database

Emissions from sexually active Anastrepha serpentine males were collected by solid-phase microextraction. Calling behavior of wild-type males showed no clear peak during the day, except that it was evident less frequently immediately after daybreak and just before dark. Calling by laboratory males...

Identification of chemicals emitted by calling males of the Sapote fruit fly, Anastrepha serpentina (Diptera: Tephritidae)

USDA-ARS?s Scientific Manuscript database

Emissions from sexually active Anastrepha serpentine males were collected by solid-phase microextraction. Calling behavior of wild-type males showed no clear peak during the day except that calling was less frequent immediately after daybreak and just before dark. Calling by laboratory males was h...

HETEROGENIC CATALYTIC HYDROLYSIS AND ANALYSIS OF NATURAL PYRETHRINS IN SUBCRITICAL WATER COUPLED WITH SOLID-PHASE MICROEXTRACTION (SPME) AND GC/MS. (R825368)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Characterization of Fish Sauce Aroma Impact Compounds Using GC-MS, SPME-Osme-GCO, and Stevens' Power Law Exponents

USDA-ARS?s Scientific Manuscript database

The objectives of this study were to characterize volatile compounds and to determine the characteristic aromas associated with impact compounds in 4 fish sauces using solid-phase micro-extraction, gas chromatography-mass spectrometry, Osme, and gas chromatography olfactometry (SPME-Osme-GCO) couple...

Solid phase microextraction method development for measuring Henry's Law constants of formaldehyde in aqueous solutions

EPA Science Inventory

Formaldehyde (HCHO) has been of special concern as an indoor air pollutant because of its existence in a wide range of products and its adverse health effects. The air-water partitioning behavior of volatile organic compounds (VOCs) such as formaldehyde is an important process th...

Passive Sampling to Measure Baseline Dissolved Persistent Organic Pollutant Concentrations in the Water Column of the Palos Verdes Shelf Superfund Site

EPA Science Inventory

Passive sampling was used to deduce water concentrations of persistent organic pollutants (POPs) in the vicinity of a marine Superfund site on the Palos Verdes Shelf, California, USA. Pre-calibrated solid phase microextraction (SPME) fibers and polyethylene (PE) strips that were...

Electropolymerized fluorinated aniline-based fiber for headspace solid-phase microextraction and gas chromatographic determination of benzaldehyde in injectable pharmaceutical formulations.

PubMed

Mohammadi, Ali; Mohammadi, Somayeh; Bayandori Moghaddam, Abdolmajid; Masoumi, Vahideh; Walker, Roderick B

2014-10-01

In this study, a simple method was developed and validated to detect trace levels of benzaldehyde in injectable pharmaceutical formulations by solid-phase microextraction coupled with gas chromatography-flame ionization detector. Polyaniline was electrodeposited on a platinum wire in trifluoroacetic acid solvent by cyclic voltammetry technique. This fiber shows high thermal and mechanical stability and high performance in extraction of benzaldehyde. Extraction and desorption time and temperature, salt effect and gas chromatography parameters were optimized as key parameters. At the optimum conditions, the fiber shows good linearity between peak area ratio of benzaldehyde/3-chlorobenzaldehyde and benzaldehyde concentration in the range of 50-800 ng/mL with percent relative standard deviation values ranging from 0.75 to 8.64% (n = 3). The limits of quantitation and detection were 50 and 16 ng/mL, respectively. The method has the requisite selectivity, sensitivity, accuracy and precision to assay benzaldehyde in injectable pharmaceutical dosage forms. © The Author [2013]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Determination of diphenylether herbicides in water samples by solid-phase microextraction coupled to liquid chromatography.

PubMed

Sheu, Hong-Li; Sung, Yu-Hsiang; Melwanki, Mahaveer B; Huang, Shang-Da

2006-11-01

Solid-phase microextraction (SPME) coupled to LC for the analysis of five diphenylether herbicides (aclonifen, bifenox, fluoroglycofen-ethyl, oxyfluorfen, and lactofen) is described. Various parameters of extraction of analytes onto the fiber (such as type of fiber, extraction time and temperature, pH, impact of salt and organic solute) and desorption from the fiber in the desorption chamber prior to separation (such as type and composition of desorption solvent, desorption mode, soaking time, and flush-out time) were studied and optimized. Four commercially available SPME fibers were studied. PDMS/divinylbenzene (PDMS/DVB, 60 microm) and carbowax/ templated resin (CW/TPR, 50 microm) fibers were selected due to better extraction efficiencies. Repeatability (RSD, < 7%), correlation coefficient (> 0.994), and detection limit (0.33-1.74 and 0.22-1.94 ng/mL, respectively, for PDMS/DVB and CW/TPR) were investigated. Relative recovery (81-104% for PDMS/DVB and 83-100% for CW/TPR fiber) values have also been calculated. The developed method was successfully applied to the analysis of river water and water collected from a vegetable garden.

Application of solid-phase microextraction to the quantitative analysis of 1,8-cineole in blood and expired air in a Eucalyptus herbivore, the brushtail possum (Trichosurus vulpecula).

PubMed

Boyle, Rebecca R; McLean, Stuart; Brandon, Sue; Pass, Georgia J; Davies, Noel W

2002-11-25

We have developed two solid-phase microextraction (SPME) methods, coupled with gas chromatography, for quantitatively analysing the major Eucalyptus leaf terpene, 1,8-cineole, in both expired air and blood from the common brushtail possum (Trichosurus vulpecula). In-line SPME sampling (5 min at 20 degrees C room temperature) of excurrent air from an expiratory chamber containing a possum dosed orally with 1,8-cineole (50 mg/kg) allowed real-time semi-quantitative measurements reflecting 1,8-cineole blood concentrations. Headspace SPME using 50 microl whole blood collected from possums dosed orally with 1,8-cineole (30 mg/kg) resulted in excellent sensitivity (quantitation limit 1 ng/ml) and reproducibility. Blood concentrations ranged between 1 and 1380 ng/ml. Calibration curves were prepared for two concentration ranges (0.05-10 and 10-400 ng/50 microl) for the analysis of blood concentrations. Both calibration curves were linear (r(2)=0.999 and 0.994, respectively) and the equations for the two concentration ranges were consistent. Copyright 2002 Elsevier Science B.V.

Classification of bacteria by simultaneous methylation-solid phase microextraction and gas chromatography/mass spectrometry analysis of fatty acid methyl esters.

PubMed

Lu, Yao; Harrington, Peter B

2010-08-01

Direct methylation and solid-phase microextraction (SPME) were used as a sample preparation technique for classification of bacteria based on fatty acid methyl ester (FAME) profiles. Methanolic tetramethylammonium hydroxide was applied as a dual-function reagent to saponify and derivatize whole-cell bacterial fatty acids into FAMEs in one step, and SPME was used to extract the bacterial FAMEs from the headspace. Compared with traditional alkaline saponification and sample preparation using liquid-liquid extraction, the method presented in this work avoids using comparatively large amounts of inorganic and organic solvents and greatly decreases the sample preparation time as well. Characteristic gas chromatography/mass spectrometry (GC/MS) of FAME profiles was achieved for six bacterial species. The difference between Gram-positive and Gram-negative bacteria was clearly visualized with the application of principal component analysis of the GC/MS data of bacterial FAMEs. A cross-validation study using ten bootstrap Latin partitions and the fuzzy rule building expert system demonstrated 87 +/- 3% correct classification efficiency.

Determination of polychlorinated biphenyls in ocean water and bovine milk using crosslinked polymeric ionic liquid sorbent coatings by solid-phase microextraction.

PubMed

Joshi, Manishkumar D; Ho, Tien D; Cole, William T S; Anderson, Jared L

2014-01-01

Crosslinked polymeric ionic liquid (PIL)-based sorbent coatings were employed in the extraction of 21 polychlorinated biphenyls (PCBs) from ocean water and bovine milk using solid-phase microextraction (SPME). The extraction temperature, time, and concentration of sodium chloride added to the matrix were optimized in order to determine the best extraction conditions for the extraction of PCBs. The analytical performance of the crosslinked PIL-based SPME fibers was compared with a commercial 7 µm polydimethylsiloxane (PDMS) fiber using gas chromatography (GC) employing an electron capture detector (ECD) and mass spectrometric detection (MS). Higher sensitivities for PCBs were achieved using PIL-based fibers when compared to PDMS fiber due to the incorporation of benzyl moieties into the PIL structures. The limits of detection (LOD) for all PCBs were determined to be in the low ng L(-1) range using the three studied coatings. Recovery studies were performed for PCBs in ocean water and bovine milk to validate the applicability of the current SPME method. © 2013 Published by Elsevier B.V.

Improved conditions for the application of solid phase microextraction prior to HPLC-FLD analysis of anatoxin-a.

PubMed

Rellán, Sandra; Gago-Martínez, Ana

2007-10-01

Solid phase microextraction coupled with high performance liquid chromatography with fluorescence detection has been optimized and evaluated for a simple, rapid, and selective analysis of anatoxin-a. Four kinds of fiber (100 microm polydimethylsiloxane, 60 microm polydimethylsiloxane/divinylbenzene, 50 microm Carbowax/templated resin-100, and 85 microm polyacrylate) were evaluated for an efficient extraction of the toxin. Parameters relating to the desorption step, such as desorption mode, solvent composition, time for both static and dynamic desorption, as well as carryover, have been studied and optimized. The derivatization process was investigated using NBD-F as derivatizing reagent. Anatoxin-a derivative was formed when the anatoxin-a-loaded fiber was inserted in a vial containing 5 microL of NBD-F. Variables affecting extraction such us ionic strength, temperature, and time have been also optimized. The results obtained showed linearity in the range of 10-2000 ng and a limit of detection of 0.29 ng/mL in river water. The presented method has been applied to different environmental samples.

Rapid screening of selective serotonin re-uptake inhibitors in urine samples using solid-phase microextraction gas chromatography-mass spectrometry.

PubMed

Salgado-Petinal, Carmen; Lamas, J Pablo; Garcia-Jares, Carmen; Llompart, Maria; Cela, Rafael

2005-07-01

In this paper a solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) method is proposed for a rapid analysis of some frequently prescribed selective serotonin re-uptake inhibitors (SSRI)-venlafaxine, fluvoxamine, mirtazapine, fluoxetine, citalopram, and sertraline-in urine samples. The SPME-based method enables simultaneous determination of the target SSRI after simple in-situ derivatization of some of the target compounds. Calibration curves in water and in urine were validated and statistically compared. This revealed the absence of matrix effect and, in consequence, the possibility of quantifying SSRI in urine samples by external water calibration. Intra-day and inter-day precision was satisfactory for all the target compounds (relative standard deviation, RSD, <14%) and the detection limits achieved were <0.4 ng mL(-1) urine. The time required for the SPME step and for GC analysis (30 min each) enables high throughput. The method was applied to real urine samples from different patients being treated with some of these pharmaceuticals. Some SSRI metabolites were also detected and tentatively identified.

On-chip sample pretreatment using a porous polymer monolithic column for solid-phase microextraction and chemiluminescence determination of catechins in green tea.

PubMed

Lin, Ling; Chen, Hui; Wei, Huibin; Wang, Feng; Lin, Jin-Ming

2011-10-21

A porous polymer monolithic column for solid-phase microextraction and chemiluminescence detection was integrated into a simple microfluidic chip for the extraction and determination of catechins in green tea. The porous polymer was prepared by poly(glycidyl methacrylate-co-ethylene dimethacrylate) and modified with ethylenediamine. Catechins can be concentrated in the porous polymer monolithic column and react with potassium permanganate to give chemiluminescence. The microfluidic chip is reusable with high sensitivity and very low reagent consumption. The on-line preconcentration and detection can be realized without an elution step. The enrichment factor was calculated to be about 20 for catechins. The relative chemiluminescence intensity increased linearly with concentration of catechin from 5.0 × 10(-9) to 1.0 × 10(-6) M and the limit of detection was 1.0 × 10(-9) M. The proposed method was applied to determine catechin in green tea. The recoveries are from 90% to 110% which benefits the actual application for green tea samples.

Submerged Cultivation of Pleurotus sapidus with Molasses: Aroma Dilution Analyses by Means of Solid Phase Microextraction and Stir Bar Sorptive Extraction.

PubMed

Trapp, Tobias; Zajul, Martina; Ahlborn, Jenny; Stephan, Alexander; Zorn, Holger; Fraatz, Marco Alexander

2018-03-14

The basidiomycete Pleurotus sapidus (PSA) was grown in submerged cultures with molasses as substrate for the production of mycelium as a protein source for food applications. The volatilomes of the substrate, the submerged culture, and the mycelia were analyzed by gas chromatography-tandem mass spectrometry-olfactometry. For compound identification, aroma dilution analyses by means of headspace solid phase microextraction and stir bar sorptive extraction were performed via variation of the split vent flow rate. Among the most potent odorants formed by PSA were arylic compounds (e.g., p-anisaldehyde), unsaturated carbonyls (e.g., 1-octen-3-one, ( E)-2-octenal, ( E, E)-2,4-decadienal), and cyclic monoterpenoids (e.g., 3,9-epoxy- p-menth-1-ene, 3,6-dimethyl-3a,4,5,7a-tetrahydro-1-benzofuran-2(3 H)-one). Several compounds from the latter group were described for the first time in Pleurotus spp. After separation of the mycelia from the medium, the aroma compounds were mainly enriched in the culture supernatant. The sensory analysis of the mycelium correlated well with the instrumental results.

Application of solid-phase microextraction for in vivo laboratory and field sampling of pharmaceuticals in fish.

PubMed

Zhou, Simon Ningsun; Oakes, Ken D; Servos, Mark R; Pawliszyn, Janusz

2008-08-15

Previous field studies utilizing solid-phase microextraction (SPME) predominantly focused on volatile and semivolatile compounds in air or water. Earlier in vivo sampling studies utilizing SPME were limited to the liquid matrix (blood). The present study has expanded the SPME technique to semisolid tissues under laboratory and field conditions through the investigation of both theoretical and applied experimental approaches. Pre-equilibrium extraction and desorption were performed in vivo in two separate animals. Excellent linearity was found between the amounts extracted by SPME from the muscle of living fish and the waterborne concentrations of pharmaceuticals. A simple SPME method is also described to simultaneously determine free and total analyte concentrations in living tissue. The utility of in vivo SPME sampling was evaluated in wild fish collected from a number of different river locations under varying degrees of influence from municipal wastewater effluents. Diphenhydramine and diltiazem were detected in the muscle of fish downstream of a local wastewater treatment plant. Based on this study, SPME demonstrated several important advantages such as simplicity, sensitivity, and robustness under laboratory and in vivo field sampling conditions.

Boron nitride nanotubes as novel sorbent for solid-phase microextraction of polycyclic aromatic hydrocarbons in environmental water samples.

PubMed

Fu, Meizhen; Xing, Hanzhu; Chen, Xiangfeng; Zhao, Rusong; Zhi, Chunyi; Wu, Chiman Lawrence

2014-09-01

Boron nitride nanotube (BNNT) is a novel material that shows potential ability in capturing organic pollutants. In this study, BNNTs fixed on a stainless steel fiber by a sol-gel technique were used as sorbent for solid-phase microextraction. Five polycyclic aromatic hydrocarbons with different numbers of aromatic rings were selected as target analysts. Gas chromatography coupled with tandem mass spectrometry was used for detection and quantitative determination. Under optimized conditions, the experimental results show a wide range of linearity (1 to 1,000 ng L(-1)), less than 10.1 % repeatability of relative standard deviation, and low detection limits (0.08 to 0.39 ng L(-1)). In addition, the fabricated fiber offered good thermal and chemical stability. The proposed method was successfully applied for the analysis of real water samples, and satisfactory results were obtained with relative recoveries ranging from 80.2 to 116.8 %. The results demonstrated that BNNTs could be used as sorbent for the analysis of environmental pollutants at trace levels.

Determination of furfural and hydroxymethylfurfural from baby formula using headspace solid phase microextraction based on nanostructured polypyrrole fiber coupled with ion mobility spectrometry.

PubMed

Kamalabadi, Mahdie; Ghaemi, Elham; Mohammadi, Abdorreza; Alizadeh, Naader

2015-08-15

Furfural (Fu) and hydroxymethylfurfural (HMFu) are extracted using a dodecylbenzenesulfonate-doped polypyrrole coating as a fiber for headspace solid phase microextraction (HS-SPME) method in baby formula samples and detected using ion mobility spectrometry (IMS). Sample pH, salt effect, extraction time and temperature were investigated and optimized as effective parameters in HS-SPME. The calibration curves were linear in the range of 20-300 ng g(-1) (R(2)>0.99). Limits of detection for Fu and HMFu were 6 ng g(-1) and 5 ng g(-1), respectively. The RSD% of Fu and HMFu for five analyses was 4.4 and 4.9, respectively. The proposed method was successfully applied to determine of Fu and HMFu in the different baby formula samples with satisfactory result. The results were in agreement with those obtained using HPLC analysis. The HS-SPME-IMS is precise, selective and sensitive analytical method for determination of Fu and HMFu in baby formula samples, without any derivatization process. Copyright © 2015 Elsevier Ltd. All rights reserved.

Direct immersion-solid phase microextraction for the determination of chlorinated pesticide residues in tomatoes by gas chromatography with an electron capture detector.

PubMed

Mariani, Maurizio Boccacci; Giannetti, Vanessa; Testani, Elena; Ceccarelli, Valentina

2013-01-01

The use of pesticides in agriculture has grown dramatically over the last decades. Environmental exposure of humans to agrochemicals is common and results in both acute and chronic health effects. In this study, direct immersion-solid phase microextraction (SPME) was coupled with electron capture detection for trace determination of 19 chlorinated pesticides in tomato samples, using a 100 pm polydimethylsiloxane fiber. The experimental parameters extraction time, extraction temperature, stirring, and salting out were evaluated and optimized. The LODs ranged from 0.5 to 8 microg/kg, and the LOQs from 5 to 30 microg/kg. A linear response was confirmed by correlation coefficients ranging from 0.97 to 0.9985. The developed method was tested by analyzing real samples purchased within the network of Italian distribution. The samples were found to be free from detectable residues of the studied pesticides. SPME has been shown to be a fast extraction technique that has several advantages such as solvent-free extraction, simplicity, and compatibility with the chromatographic analytical system.

Electrodeposited polyaniline as a fiber coating for solid-phase microextraction of organochlorine pesticides from water.

PubMed

Li, Xiang; Zhong, Ming; Chen, Jianmin

2008-08-01

The study on the performance of polyaniline as a fiber coating for solid-phase microextraction (SPME) purposes has been reported. Polyaniline coatings were directly electrodeposited on the surface of a stainless steel wire and applied for the extraction of some organochlorine pesticides (OCPs) from water samples. Analyses were performed using GC-electron capture detection (GC-ECD). The results obtained show that polyaniline fiber coating is suitable for the successful extraction of organochlorine compounds. This behavior is most probably due to the porous surface structure of polyaniline film, which provides large surface areas and allowed for high extraction efficiency. Experimental parameters such as adsorption and desorption conditions were studied and optimized. The optimized method has an acceptable linearity, with a concentration range of 1-5000 ng/L. Single fiber repeatability and fiber-to-fiber reproducibility were less than 12 and 17%, respectively. High environmental resistance and lower cost are among the advantages of polyaniline fibers over commercially available SPME fibers. The developed method was applied to the analysis of real water samples from Yangtse River and Tianmu Lake.

Speciation of butyltin compounds in marine sediments with headspace solid phase microextraction and gas chromatography mass spectrometry.

PubMed

Cardellicchio, N; Giandomenico, S; Decataldo, A; Di Leo, A

2001-03-01

A method for the determination of organotin compounds (monobutyl = MBT, dibutyl = DBT, and tributyltin = TBT) in marine sediments by headspace Solid Phase Microextraction (SPME) has been developed. The analytical procedure involved 1) extraction of TBT, DBT and MBT from sediments with HCl and methanol mixture, 2) in situ derivatization with sodium tetraethylborate and 3) headspace SPME extraction using a fiber coated with poly(dimethylsiloxane). The derivatized organotin compounds were desorbed into the splitless injector and simultaneously analyzed by gas chromatography - mass spectrometry. The analytical method was optimized with respect to derivatization reaction and extraction conditions. The detection limits obtained for MBT, DBT and TBT ranged from 730 to 969 pg/g as Sn dry weight. Linear calibration curves were obtained for all analytes in the range of 30-1000 ng/L as Sn. Analysis of a standard reference sediment (CRM 462) demonstrates the suitability of this method for the determination of butyltin compounds in marine sediments. The application to the determination of TBT, DBT and MBT in a coastal marine sediment is shown.

Gas-Purged Headspace Liquid Phase Microextraction System for Determination of Volatile and Semivolatile Analytes

PubMed Central

Zhang, Meihua; Bi, Jinhu; Yang, Cui; Li, Donghao; Piao, Xiangfan

2012-01-01

In order to achieve rapid, automatic, and efficient extraction for trace chemicals from samples, a system of gas-purged headspace liquid phase microextraction (GP-HS-LPME) has been researched and developed based on the original HS-LPME technique. In this system, semiconductor condenser and heater, whose refrigerating and heating temperatures were controlled by microcontroller, were designed to cool the extraction solvent and to heat the sample, respectively. Besides, inert gas, whose gas flow rate was adjusted by mass flow controller, was continuously introduced into and discharged from the system. Under optimized parameters, extraction experiments were performed, respectively, using GP-HS-LPME system and original HS-LPME technique for enriching volatile and semivolatile target compounds from the same kind of sample of 15 PAHs standard mixture. GC-MS analysis results for the two experiments indicated that a higher enrichment factor was obtained from GP-HS-LPME. The enrichment results demonstrate that GP-HS-LPME system is potential in determination of volatile and semivolatile analytes from various kinds of samples. PMID:22448341

Dye-doped nanostructure polypyrrole film for electrochemically switching solid-phase microextraction of Ni(II) and ICP-OES analysis of waste water.

PubMed

Shamaeli, Ehsan; Alizadeh, Naader

2012-01-01

A nanostructure fiber based on conducting polypyrrole synthesized by an electrochemical method has been developed, and used for electrochemically switching solid-phase microextraction (ES-SPME). The ES-SPME was prepared by the doping of eriochrome blue in polypyrrole (PPy-ECB) and used for selectively extracting the Ni(II) cation in the presence of some transition and heavy metal ions. The cation-exchange behavior of electrochemically prepared polypyrrole on stainless-steel with and without eriochrome blue (ECB) dye was characterized using ICP-OES analysis. The effects of the scan rate for electrochemical synthesis, uptake and the release potential on the extraction behavior of the PPy-ECB conductive fiber were studied. Uptake and release time profiles show that the process of electrically switched cation exchange could be completed within 250 s. The results of the present study point concerning the possibility of developing a selective extraction process for Ni(II) from waste water was explored using such a nanostructured PPy-ECB film through an electrically switched cation exchange. 2012 © The Japan Society for Analytical Chemistry

Assessment of strobilurin fungicides' content in soya-based drinks by liquid micro-extraction and liquid chromatography with tandem mass spectrometry.

PubMed

Campillo, Natalia; Iniesta, María Jesús; Viñas, Pilar; Hernández-Córdoba, Manuel

2015-01-01

Seven strobilurin fungicides were pre-concentrated from soya-based drinks using dispersive liquid-liquid micro-extraction (DLLME) with a prior protein precipitation step in acid medium. The enriched phase was analysed by liquid chromatography (LC) with dual detection, using diode array detection (DAD) and electrospray-ion trap tandem mass spectrometry (ESI-IT-MS/MS). After selecting 1-undecanol and methanol as the extractant and disperser solvents, respectively, for DLLME, the Taguchi experimental method, an orthogonal array design, was applied to select the optimal solvent volumes and salt concentration in the aqueous phase. The matrix effect was evaluated and quantification was carried out using external aqueous calibration for DAD and matrix-matched calibration method for MS/MS. Detection limits in the 4-130 and 0.8-4.5 ng g(-1) ranges were obtained for DAD and MS/MS, respectively. The DLLME-LC-DAD-MS method was applied to the analysis of 10 different samples, none of which was found to contain residues of the studied fungicides.

Solid-phase microextraction of phthalate esters by a new coating based on a thermally stable polypyrrole/graphene oxide composite.

PubMed

Jafari, Mostafa; Ebrahimzadeh, Homeira; Banitaba, Mohammad Hossein; Davarani, Saied Saeed Hosseiny

2014-11-01

A novel polypyrole/graphene oxide coating was made by the electrochemical polymerization of pyrrole in the presence of sodium dodecyl sulfate and graphene oxide on a platinum wire. The prepared fiber has shown a good thermal stability up to 300°C. The fiber was applied to the direct solid-phase microextraction and gas chromatographic analysis of four phthalate esters. The effect of four parameters on gas chromatography peak area including extraction temperature, extraction time, injection temperature, and ionic strength were investigated. Under the optimized conditions, the detection limits were between 0.042 and 0.26 μg/L. The intraday and interday relative standard deviations obtained at 55 μg/L, using a single fiber, were 8.2-16% and 17.3-25.6%, respectively. The method was successfully applied to the analysis of phthalate esters in two real samples of boiling water in cheap disposable clear plastic drinking cups showing recoveries from 83 to 120%. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of spirocyclic tetronic/tetramic acid derivatives and neonicotinoid insecticides in fruits and vegetables by liquid chromatography and mass spectrometry after dispersive liquid-liquid microextraction.

PubMed

Pastor-Belda, Marta; Garrido, Isabel; Campillo, Natalia; Viñas, Pilar; Hellín, Pilar; Flores, Pilar; Fenoll, José

2016-07-01

Dispersive liquid-liquid microextraction was used to preconcentrate three spirocyclic tetronic/tetramic acid derivatives (spirotetramat, spiromesifen and spirodiclofen) and five neonicotinoid (thiamethoxam, chlotianidin, imidacloprid, acetamiprid and thiacloprid) insecticides previously extracted from fruit and vegetable matrices with acetonitrile. The organic enriched phase was evaporated, reconstituted in 25μL acetonitrile and analyzed by reversed-phase liquid chromatography with tandem mass spectrometry using a triple quadrupole in selected reaction monitoring mode. Enrichment factors in the 15-100 range were obtained. A matrix effect was observed, the detection limits varying between 0.025 and 0.5ngg(-1), depending on the compound and the sample matrix. The developed method was applied to the analysis of 25 samples corresponding to five different fruit and vegetable matrices. Only thiamethoxam was detected in a lemon sample at a concentration close to the quantification limit, and spiromesifen and spirotetramat at concentrations between 11.6 and 54.5ngg(-1). Copyright © 2016 Elsevier Ltd. All rights reserved.

Dispersive liquid-liquid microextraction based on the solidification of floating organic droplet for the determination of polychlorinated biphenyls in aqueous samples.

PubMed

Dai, Liping; Cheng, Jing; Matsadiq, Guzalnur; Liu, Lu; Li, Jun-Kai

2010-08-03

In the proposed method, an extraction solvent with a lower toxicity and density than the solvents typically used in dispersive liquid-liquid microextraction was used to extract seven polychlorinated biphenyls (PCBs) from aqueous samples. Due to the density and melting point of the extraction solvent, the extract which forms a layer on top of aqueous sample can be collected by solidifying it at low temperatures, which form a layer on top of the aqueous sample. Furthermore, the solidified phase can be easily removed from the aqueous phase. Based on preliminary studies, 1-undecanol was selected as the extraction solvent, and a series of parameters that affect the extraction efficiency were systematically investigated. Under the optimized conditions, enrichment factors for PCBs ranged between 494 and 606. Based on a signal-to-noise ratio of 3, the limit of detection for the method ranged between 3.3 and 5.4 ng L(-1). Good linearity, reproducibility and recovery were also obtained. 2010 Elsevier B.V. All rights reserved.

Enrichment and determination of octylphenol and nonylphenol in environmental water samples by solid-phase microextraction with carboxylated carbon nano-spheres coating prior to gas chromatography-mass spectrometry.

PubMed

Gong, Sheng-Xiang; Wang, Xia; Li, Lei; Wang, Ming-Lin; Zhao, Ru-Song

2015-11-01

In this paper, a novel and simple method for the sensitive determination of endocrine disrupter compounds octylphenol (OP) and nonylphenol (NP) in environmental water samples has been developed using solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry. Carboxylated carbon nano-spheres (CNSs-COOH) are used as a novel SPME coating via physical adhesion. The CNSs-COOH fiber possessed higher adsorption efficiency than 100 μm polydimethysiloxane (PDMS) fiber and was similar to 85 μm polyacrylate (PA) fiber for the two analytes. Important parameters, such as extraction time, pH, agitation speed, ionic strength, and desorption temperature and time, were investigated and optimized in detail. Under the optimal parameters, the developed method achieved low limits of detection of 0.13~0.14 ng·L(-1) and a wide linear range of 1~1000 ng·(-1) for OP and NP. The novel method was validated with several real environmental water samples, and satisfactory results were obtained.

Monolithic molecular imprinted polymer fiber for recognition and solid phase microextraction of ephedrine and pseudoephedrine in biological samples prior to capillary electrophoresis analysis.

PubMed

Deng, Dong-Li; Zhang, Ji-You; Chen, Chen; Hou, Xiao-Ling; Su, Ying-Ying; Wu, Lan

2012-01-06

A novel capillary electrophoresis (CE) method coupled with monolithic molecular imprinted polymer (MIP) fiber based solid phase microextraction (SPME) was developed for selective and sensitive determination of ephedrine (E) and pseudoephedrine (PE). With in situ polymerization in a silica capillary mold and E as template, the MIP fibers could be produced in batch reproducibly and each fiber was available for 50 extraction cycles without significant decrease in extraction ability. Using the MIP fiber under optimized extraction conditions, CE detection limits of E and PE were greatly lowered from 0.20 to 0.00096 μg/mL and 0.12 to 0.0011 μg/mL, respectively. Analysis of urine and serum samples by the MIP-SPME-CE method was also performed, with results indicating that E and PE could be selectively extracted. The recoveries and relative standard deviations (RSDs) for sample analysis were found in the range of 91-104% and 3.8-9.1%, respectively. Copyright © 2011 Elsevier B.V. All rights reserved.

Characterization of solid-phase microextraction and gas chromatography for the analysis of gasoline tracers in different microenvironments.

PubMed

Ceballos, Diana; Zielinska, Barbara; Fujita, Eric; Sagebiel, John

2007-03-01

Gasoline tracers were collected on solid-phase microextraction (SPME) fibers and analyzed by capillary gas chromatography with photoionization detector (GC/PID). This was part of a larger study to quantify personal exposure to motor vehicle gasoline evaporative and combustive emissions in high-end exposure microenvironments (MEs). The SPME fiber selected for this application was a 75-microm carboxen/polydimethylsiloxane. Sequential 10-min samples were collected for measurement of benzene, toluene, ethylbenzene, and ortho-, meta-, and para-xylene in different MEs in Atlanta, GA, in summer 2002 and Reno, NV, in spring 2003. Field calibrations were performed with certified gas standards in 1-L Tedlar bags for varying concentrations and exposure times. SPME detection limits were approximately 0.2 ppbv with a precision of 3-17% and accuracy of 30%. A dynamic system was designed for temperature and relative humidity calibrations, with corrections for the effects of these variables performed when necessary. SPME data compared satisfactorily with integrated canister samples, continuous PID, and field portable mass spectrometer data.

Ionic liquids in solid-phase microextraction: a review.

PubMed

Ho, Tien D; Canestraro, Anthony J; Anderson, Jared L

2011-06-10

Solid-phase microextraction (SPME) has undergone a surge in popularity within the field of analytical chemistry in the past two decades since its introduction. Owing to its nature of extraction, SPME has become widely known as a quick and cost-effective sample preparation technique. Although SPME has demonstrated extraordinary versatility in sampling capabilities, the technique continues to experience a tremendous growth in innovation. Presently, increasing efforts have been directed towards the engineering of novel sorbent material in order to expand the applicability of SPME for a wider range of analytes and matrices. This review highlights the application of ionic liquids (ILs) and polymeric ionic liquids (PILs) as innovative sorbent materials for SPME. Characterized by their unique physico-chemical properties, these compounds can be structurally-designed to selectively extract target analytes based on unique molecular interactions. To examine the advantages of IL and PIL-based sorbent coatings in SPME, the field is reviewed by gathering available experimental data and exploring the sensitivity, linear calibration range, as well as detection limits for a variety of target analytes in the methods that have been developed. Copyright © 2011 Elsevier B.V. All rights reserved.

Speciation analysis of organotin compounds in human urine by headspace solid-phase micro-extraction and gas chromatography with pulsed flame photometric detection.

PubMed

Valenzuela, Aníbal; Lespes, Gaëtane; Quiroz, Waldo; Aguilar, Luis F; Bravo, Manuel A

2014-07-01

A new headspace solid-phase micro-extraction (HS-SPME) method followed by gas chromatography with pulsed flame photometric detection (GC-PFPD) analysis has been developed for the simultaneous determination of 11 organotin compounds, including methyl-, butyl-, phenyl- and octyltin derivates, in human urine. The methodology has been validated by the analysis of urine samples fortified with all analytes at different concentration levels, and recovery rates above 87% and relative precisions between 2% and 7% were obtained. Additionally, an experimental-design approach has been used to model the storage stability of organotin compounds in human urine, demonstrating that organotins are highly degraded in this medium, although their stability is satisfactory during the first 4 days of storage at 4 °C and pH=4. Finally, this methodology was applied to urine samples collected from harbor workers exposed to antifouling paints; methyl- and butyltins were detected, confirming human exposure in this type of work environment. Copyright © 2014 Elsevier B.V. All rights reserved.

Multiple headspace-solid-phase microextraction: an application to quantification of mushroom volatiles.

PubMed

Costa, Rosaria; Tedone, Laura; De Grazia, Selenia; Dugo, Paola; Mondello, Luigi

2013-04-03

Multiple headspace-solid phase microextraction (MHS-SPME) followed by gas chromatography/mass spectrometry (GC-MS) and flame ionization detection (GC-FID) was applied to the identification and quantification of volatiles released by the mushroom Agaricus bisporus, also known as champignon. MHS-SPME allows to perform quantitative analysis of volatiles from solid matrices, free of matrix interferences. Samples analyzed were fresh mushrooms (chopped and homogenized) and mushroom-containing food dressings. 1-Octen-3-ol, 3-octanol, 3-octanone, 1-octen-3-one and benzaldehyde were common constituents of the samples analyzed. Method performance has been tested through the evaluation of limit of detection (LoD, range 0.033-0.078 ng), limit of quantification (LoQ, range 0.111-0.259 ng) and analyte recovery (92.3-108.5%). The results obtained showed quantitative differences among the samples, which can be attributed to critical factors, such as the degree of cell damage upon sample preparation, that are here discussed. Considerations on the mushrooms biochemistry and on the basic principles of MHS analysis are also presented. Copyright © 2013 Elsevier B.V. All rights reserved.

Electroplating of nanostructured polyaniline-polypyrrole composite coating in a stainless-steel tube for on-line in-tube solid phase microextraction.

PubMed

Asiabi, Hamid; Yamini, Yadollah; Seidi, Shahram; Esrafili, Ali; Rezaei, Fatemeh

2015-06-05

In this work, a novel and efficient on-line in-tube solid phase microextraction method followed by high performance liquid chromatography was developed for preconcentration and determination of trace amounts of parabens. A nanostructured polyaniline-polypyrrole composite was electrochemically deposited on the inner surface of a stainless steel tube and used as the extraction phase. Several important factors that influence the extraction efficiency, including type of solid-phase coating, extraction and desorption times, flow rates of the sample solution and eluent, pH, and ionic strength of the sample solution were investigated and optimized. Under the optimal conditions, the limits of detection were in the range of 0.02-0.04 μg L(-1). This method showed good linearity for parabens in the range of 0.07-50 μg L(-1), with coefficients of determination better than 0.998. The intra- and inter-assay precisions (RSD%, n=3) were in the range of 5.9-7.0% and 4.4-5.7% at three concentration levels of 2, 10, and 20 μg L(-1), respectively. The extraction recovery values for the spiked samples were in the acceptable range of 80.3-90.2%. The validated method was successfully applied for analysis of methyl-, ethyl-, and propyl parabens in some water, milk, and juice samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Estimation of the toxicity of sulfadiazine to Daphnia magna using negligible depletion hollow-fiber liquid-phase microextraction independent of ambient pH

PubMed Central

Liu, Kailin; Xu, Shiji; Zhang, Minghuan; Kou, Yahong; Zhou, Xiaomao; Luo, Kun; Hu, Lifeng; Liu, Xiangying; Liu, Min; Bai, Lianyang

2016-01-01

The toxicity of ionizable organic compounds to organisms depends on the pH, which therefore affects risk assessments of these compounds. However, there is not a direct chemical method to predict the toxicity of ionizable organic compounds. To determine whether hollow-fiber liquid-phase microextraction (HF-LPME) is applicable for this purpose, a three-phase HF-LPME was used to measure sulfadiazine and estimate its toxicity to Daphnia magna in solutions of different pH. The result indicated that the sulfadiazine concentrations measured by HF-LPME decreased with increasing pH, which is consistent with the decreased toxicity. The concentration immobilize 50% of the daphnids (EC50) in 48 h calculated from nominal concentrations increased from 11.93 to 273.5 mg L−1 as the pH increased from 6.0 to 8.5, and the coefficient of variation (CV) of the EC50 values reached 104.6%. When calculated from the concentrations measured by HF-LPME (pH 12 acceptor phase), the EC50 ranged from 223.4 to 394.6 mg L−1, and the CV decreased to 27.60%, suggesting that the concentrations measured by HF-LPME can be used to estimate the toxicity of sulfadiazine irrespective of the solution pH. PMID:28004779

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.

Silica aerogel coated on metallic wire by phase separation of polystyrene for in-tube solid phase microextraction.

PubMed

Baktash, Mohammad Yahya; Bagheri, Habib

2017-06-02

In this research, an attempt was made toward synthesizing a sol-gel-based silica aerogel and its subsequent coating on a copper wire by phase separation of polystyrene. Adaption of this new approach enabled us to coat the metallic wire with powder materials. The use of this method for coating, led to the formation of a porous and thick structure of silica aerogel. The coated wire was placed in a needle and used as the sorbent for in-tube solid phase microextraction of chlorobenzenes (CBs). The superhydrophobicity of sorbent on extraction efficiency was investigated by using different ratios of tetraethylorthosilicate/methyltrimethoxysilane. The surface coated with the prepared silica aerogel by the phase separation of polystyrene showed high contact angle, approving the desired superhydrophobic properties. Effects of major parameters influencing the extraction efficiency including the extraction temperature, extraction time, ionic strength, desorption time were investigated and optimized. The limits of detection and quantification of the method under the optimized condition were 0.1-1.2 and 0.4-4.1ngL -1 , respectively. The relative standard deviations (RSD%) at a concentration level of 10ngL -1 were between 4 and 10% (n=3). The calibration curves of CBs showed linearity from 1 to100ngL -1 . Eventually, the method was successfully applied to the extraction of model compounds from real water samples and relative recoveries varied from 88 to 115%. Copyright © 2017 Elsevier B.V. All rights reserved.

Overcoming the challenges of conventional dispersive liquid-liquid microextraction: analysis of THMs in chlorinated swimming pools.

PubMed

Faraji, Hakim; Helalizadeh, Masoumeh; Kordi, Mohammad Reza

2018-01-01

A rapid, simple, and sensitive approach to the analysis of trihalomethanes (THMs) in swimming pool water samples has been developed. The main goal of this study was to overcome or to improve the shortcomings of conventional dispersive liquid-liquid microextraction (DLLME) and to maximize the realization of green analytical chemistry principles. The method involves a simple vortex-assisted microextraction step, in the absence of the dispersive solvent, followed by salting-out effect for the elimination of the centrifugation step. A bell-shaped device and a solidifiable solvent were used to simplify the extraction solvent collection after phase separation. Optimization of the independent variables was performed by using chemometric methods in three steps. The method was statistically validated based on authentic guidance documents. The completion time for extraction was less than 8 min, and the limits of detection were in the range between 4 and 72 ng L -1 . Using this method, good linearity and precision were achieved. The results of THMs determination in different real samples showed that in some cases the concentration of total THMs was more than threshold values of THMs determined by accredited healthcare organizations. This method indicated satisfactory analytical figures of merit. Graphical Abstract A novel green microextraction technique for overcoming the challenges of conventional DLLME. The proposed procedure complies with the principles of green/sustainable analytical chemistry, comprising decreasing the sample size, making easy automation of the process, reducing organic waste, diminishing energy consumption, replacing toxic reagents with safer reagents, and enhancing operator safety.