Identification of clinical isolates of mycobacteria with gas-liquid chromatography: a 10-month follow-up study.

PubMed Central

Tisdall, P A; DeYoung, D R; Roberts, G D; Anhalt, J P

1982-01-01

Identification of routine mycobacterial isolates by gas-liquid chromatography profile analysis was performed on 335 strains received at the Mayo Clinic over a 10-month period. Comparison of identification by gas-liquid chromatography versus conventional biochemical profiles was made. The two methods agreed on the identification of 320 isolates, with gas-liquid chromatography profiling making eight errors and biochemical profiling making four errors. In three cases, discrepancies could not be resolved. PMID:6811612

Investigating the Retention Mechanisms of Liquid Chromatography Using Solid-Phase Extraction Cartridges

ERIC Educational Resources Information Center

O'Donnell, Mary E.; Musial, Beata A.; Bretz, Stacey Lowery; Danielson, Neil D.; Ca, Diep

2009-01-01

Liquid chromatography (LC) experiments for the undergraduate analytical laboratory course often illustrate the application of reversed-phase LC to solve a separation problem, but rarely compare LC retention mechanisms. In addition, a high-performance liquid chromatography instrument may be beyond what some small colleges can purchase. Solid-phase…

Advances in native high-performance liquid chromatography and intact mass spectrometry for the characterization of biopharmaceutical products.

PubMed

Tassi, Marco; De Vos, Jelle; Chatterjee, Sneha; Sobott, Frank; Bones, Jonathan; Eeltink, Sebastiaan

2018-01-01

The characterization of biotherapeutics represents a major analytical challenge. This review discusses the current state-of-the-art in analytical technologies to profile biopharma products under native conditions, i.e., the protein three dimensional conformation is maintained during liquid chromatographic analysis. Native liquid-chromatographic modes that are discussed include aqueous size-exclusion chromatography, hydrophobic interaction chromatography, and ion-exchange chromatography. Infusion conditions and the possibilities and limitations to hyphenate native liquid chromatography to mass spectrometry are discussed. Furthermore, the applicability of native liquid-chromatography methods and intact mass spectrometry analysis for the characterization of monoclonal antibodies and antibody-drug conjugates is discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

40 CFR Appendix A to Subpart C of... - Alternative Testing Methods Approved for Analyses Under the Safe Drinking Water Act

Code of Federal Regulations, 2013 CFR

2013-07-01

... Chromatography/Mass Spectrometry (GC/MS) 525.3 24 Carbofuran High-performance liquid chromatography (HPLC) with... (HPLC) with Post-Column Derivatization and Fluorescence Detection 6651 B 6651 B 6651 B-00. Heptachlor... Spectrometry (GC/MS) 525.3 24 Oxamyl High-performance liquid chromatography (HPLC) with post-column...

Fast and comprehensive analysis of secondary metabolites in cocoa products using ultra high-performance liquid chromatography directly after pressurized liquid extraction.

PubMed

Damm, Irina; Enger, Eileen; Chrubasik-Hausmann, Sigrun; Schieber, Andreas; Zimmermann, Benno F

2016-08-01

Fast methods for the extraction and analysis of various secondary metabolites from cocoa products were developed and optimized regarding speed and separation efficiency. Extraction by pressurized liquid extraction is automated and the extracts are analyzed by rapid reversed-phase ultra high-performance liquid chromatography and normal-phase high-performance liquid chromatography methods. After extraction, no further sample treatment is required before chromatographic analysis. The analytes comprise monomeric and oligomeric flavanols, flavonols, methylxanthins, N-phenylpropenoyl amino acids, and phenolic acids. Polyphenols and N-phenylpropenoyl amino acids are separated in a single run of 33 min, procyanidins are analyzed by normal-phase high-performance liquid chromatography within 16 min, and methylxanthins require only 6 min total run time. A fourth method is suitable for phenolic acids, but only protocatechuic acid was found in relevant quantities. The optimized methods were validated and applied to 27 dark chocolates, one milk chocolate, two cocoa powders and two food supplements based on cocoa extract. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Screening anti-tumor compounds from Ligusticum wallichii using cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry.

PubMed

Zhang, Tao; Ding, Yuanyuan; An, Hongli; Feng, Liuxin; Wang, Sicen

2015-07-14

Tyrosine 367 Cysteine-fibroblast growth factor receptor 4 cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry was developed. Tyrosine 367 Cysteine-HEK293 cells were used as cell membrane stationary phase. Specificity and reproducibility of the cell membrane chromatography was evaluated using 1-tert-butyl-3-{2-[4-(diethylamino)butylamino]-6-(3,5-dimethoxyphenyl)pyrido[2,3-d]pyrimidin-7-yl}urea, Nimodipine and dexamethasone acetate. Then, anti-tumor components acting on Tyrosine 367 Cysteine-fibroblast growth factor receptor 4 were screened and identified from extracts of Ligusticum wallichii. Components from the extract were retained on the cell membrane chromatographic column. The retained fraction was directly eluted into high-performance liquid chromatography with mass spectrometry system for separation and identification. Finally, Levistolide A was identified as an active component from Ligusticum wallichii extracts. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide-formazan colorimetric assay revealed that Levistolide A inhibits proliferation of overexpressing the mutated receptor cells with dose-dependent manner. Phosphorylation of fibroblast growth factor receptor 4 was also decrease under Levistolide A treatment. Flex dock simulation verified that Levistolide A could bind with the tyrosine kinase domain of fibroblast growth factor receptor 4. Therefore, Levistolide A screened by the cell membrane chromatography combined with high-performance liquid chromatography and mass spectrometry can arrest cell growth. In conclusion, the two-dimensional high-performance liquid chromatography method can screen and identify potential anti-tumor ingredients which specifically act on the tyrosine kinase domain of the mutated fibroblast growth factor receptor 4. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

High-performance liquid chromatography separation of unsaturated organic compounds by a monolithic silica column embedded with silver nanoparticles.

PubMed

Zhu, Yang; Morisato, Kei; Hasegawa, George; Moitra, Nirmalya; Kiyomura, Tsutomu; Kurata, Hiroki; Kanamori, Kazuyoshi; Nakanishi, Kazuki

2015-08-01

The optimization of a porous structure to ensure good separation performances is always a significant issue in high-performance liquid chromatography column design. Recently we reported the homogeneous embedment of Ag nanoparticles in periodic mesoporous silica monolith and the application of such Ag nanoparticles embedded silica monolith for the high-performance liquid chromatography separation of polyaromatic hydrocarbons. However, the separation performance remains to be improved and the retention mechanism as compared with the Ag ion high-performance liquid chromatography technique still needs to be clarified. In this research, Ag nanoparticles were introduced into a macro/mesoporous silica monolith with optimized pore parameters for high-performance liquid chromatography separations. Baseline separation of benzene, naphthalene, anthracene, and pyrene was achieved with the theoretical plate number for analyte naphthalene as 36,000 m(-1). Its separation function was further extended to cis/trans isomers of aromatic compounds where cis/trans stilbenes were chosen as a benchmark. Good separation of cis/trans-stilbene with separation factor as 7 and theoretical plate number as 76,000 m(-1) for cis-stilbene was obtained. The trans isomer, however, is retained more strongly, which contradicts the long- established retention rule of Ag ion chromatography. Such behavior of Ag nanoparticles embedded in a silica column can be attributed to the differences in the molecular geometric configuration of cis/trans stilbenes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dissolution of NTO, DNAN, and Insensitive Munitions Formulations and Their Fates in Soils

DTIC Science & Technology

2014-09-01

3 2 Mass loss measured by high precision liquid chromatography (HPLC) versus measured mass loss by... Liquid Chromatography IM Insensitive Munitions IMX Insensitive Munitions eXplosive k First-Order Transformation Rate Constant kphoto First...Performance Liquid Chromatography U.S. EPA United States Environmental Protection Agency WMRD Weapons and Materials Research Directorate ERDC/CRREL

76 FR 61647 - Receipt of Several Pesticide Petitions Filed for Residues of Pesticide Chemicals in or on Various...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-05

... was required for gas chromatography with mass selective detection (GC/MSD) but not for liquid... detection (LOD = 0.01) and a gas liquid chromatography (GLC) method with a flame photometric detection (LOD... quantification by high performance liquid chromatography with tandem mass spectrometric detection (HPLC/MS/MS...

Quantitative analysis of phylloquinone (vitamin K1) in soy bean oils by high-performance liquid chromatography.

PubMed

Zonta, F; Stancher, B

1985-07-19

A high-performance liquid chromatographic method for determining phylloquinone (vitamin K1) in soy bean oils is described. Resolution of vitamin K1 from interfering peaks of the matrix was obtained after enzymatic digestion, extraction and liquid-solid chromatography on alumina. An isocratic reversed-phase chromatography with UV detection was used in the final stage. The quantitation was carried out by the standard addition method, and the recovery of the whole procedure was 88.2%.

40 CFR Appendix A to Subpart C of... - Alternative Testing Methods Approved for Analyses Under the Safe Drinking Water Act

Code of Federal Regulations, 2014 CFR

2014-07-01

... Spectrometry (GC/MS) 525.3 24 Carbofuran High-performance liquid chromatography (HPLC) with post-column... (HPLC) with Post-Column Derivatization and Fluorescence Detection 6651 B 6651 B 6651 B-00, B-05... Chromatography/Mass Spectrometry (GC/MS) 525.3 24 Oxamyl High-performance liquid chromatography (HPLC) with post...

Quantification of Quercetin and Rutin from Benincasa hispida Seeds and Carissa Congesta Roots by High-performance Thin Layer Chromatography and High-performance Liquid Chromatography.

PubMed

Doshi, Gaurav Mahesh; Une, Hemant Devidas

2016-01-01

In Indian Ayurvedic system, Benincasa hispida (BH) and Carissa congesta (CC) are well-known plants used for major and minor ailments. BH has been regarded as Kushmanda, whereas CC has been used in immune-related disorders of the human system. Quercetin and rutin identified from the vast plethora of plant extracts have proved to possess ethnopharmacological relevance. In present studies, we have determined quercetin and rutin in terms of percentage in BH seeds and CC roots by high-performance thin layer chromatography (HPTLC) and high-performance liquid chromatography (HPLC). After extraction and phytochemical screening, the extracts were subjected to quantification for the presence of quercetin and rutin by HPTLC and HPLC. HPTLC showed quercetin as 44.60, 27.13% and rutin as 32.00, 36.31% w/w, whereas HPLC revealed quercetin as 34.00, 35.00% and rutin as 21.99, 45.03% w/v in BH and CC extracts, respectively. The BH and CC extracts have elucidated peaks that were corresponding with standard peaks on undertaking chromatographic studies. Quercetin and rutin are isolated from BH seeds and CC roots by High Performance. Thin Layer Chromatography and High Performance Liquid Chromatography. HPTLC revealed presence of quercetin as 44.60, 27.13 % and rutin as 32.00, 36.31 % w/w. HPLC revealed presence of quercetin as 34.00, 35.00 % and rutin as 21.99, 45.03 % w/v. Abbreviation Used: HPTLC: High Performance Thin Layer Chromatography; HPLC: High Pressure Liquid Chromatography, UV: Ultraviolet, CC: Carissa congesta, BH: Benincasa hispida.

High-Performance Liquid Chromatography-Mass Spectrometry.

ERIC Educational Resources Information Center

Vestal, Marvin L.

1984-01-01

Reviews techniques for online coupling of high-performance liquid chromatography with mass spectrometry, emphasizing those suitable for application to nonvolatile samples. Also summarizes the present status, strengths, and weaknesses of various techniques and discusses potential applications of recently developed techniques for combined liquid…

Determination of proenkephalin products in brain tissue by high-performance liquid chromatography and a modified bioassay procedure.

PubMed

Bailey, C; Kitchen, I

1985-06-01

A method is described for the separation of proenkephalin products using gradient high-performance liquid chromatography preceded by Sep-Pak chromatography. Samples can be assayed simply by use of a modified mouse vas deferens bioassay which is sufficiently sensitive for most applications. The preliminary Sep-Pak chromatography method excludes alpha-neoendorphin and the dynorphins and thus provides a suitable procedure for separation of prodynorphin and proenkephalin products.

High Performance Thin Layer Chromatography.

ERIC Educational Resources Information Center

Costanzo, Samuel J.

1984-01-01

Clarifies where in the scheme of modern chromatography high performance thin layer chromatography (TLC) fits and why in some situations it is a viable alternative to gas and high performance liquid chromatography. New TLC plates, sample applications, plate development, and instrumental techniques are considered. (JN)

High-Performance Liquid Chromatography in the Undergraduate Chemical Engineering Laboratory

ERIC Educational Resources Information Center

Frey, Douglas D.; Guo, Hui; Karnik, Nikhila

2013-01-01

This article describes the assembly of a simple, low-cost, high-performance liquid chromatography (HPLC) system and its use in the undergraduate chemical engineering laboratory course to perform simple experiments. By interpreting the results from these experiments students are able to gain significant experience in the general method of…

Ionic-liquid-based ultrasound-assisted extraction of isoflavones from Belamcanda chinensis and subsequent screening and isolation of potential α-glucosidase inhibitors by ultrafiltration and semipreparative high-performance liquid chromatography.

PubMed

Li, Senlin; Li, Sainan; Huang, Yu; Liu, Chunming; Chen, Lina; Zhang, Yuchi

2017-06-01

The separation of a compound of interest from its structurally similar homologues to produce high-purity natural products is a challenging problem. This work proposes a novel method for the separation of iristectorigenin A from its structurally similar homologues by ionic-liquid-based ultrasound-assisted extraction and the subsequent screening and isolation of potential α-glucosidase inhibitors via ultrafiltration and semipreparative high-performance liquid chromatography. Ionic-liquid-based ultrasound-assisted extraction was successfully applied to the extraction of tectorigenin, iristectorigenin A, irigenin, and irisflorentin from Belamcanda chinensis. The optimum conditions for the efficient extraction of isoflavones were determined as 1.0 M 1-ethyl-3-methylimidazolium tetrafluoroborate with extraction time of 30 min and a solvent to solid ratio of 30 mL/g. Ultrafiltration with liquid chromatography and mass spectrometry was applied to screen and identify α-glucosidase inhibitors from B. chinensis, followed by the application of semipreparative high-performance liquid chromatography to separate and isolate the active constituents. Four major compounds including tectorigenin, iristectorigenin A, irigenin, and irisflorentin were screened and identified as α-glucosidase inhibitors, and then the four active compounds abovementioned were subsequently isolated by semipreparative high-performance liquid chromatography (99.89, 88.97, 99.79, and 99.97% purity, respectively). The results demonstrate that ionic liquid extraction can be successfully applied to the extraction of isoflavones from B. chinensis. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of Caffeine in Beverages by High Performance Liquid Chromatography.

ERIC Educational Resources Information Center

DiNunzio, James E.

1985-01-01

Describes the equipment, procedures, and results for the determination of caffeine in beverages by high performance liquid chromatography. The method is simple, fast, accurate, and, because sample preparation is minimal, it is well suited for use in a teaching laboratory. (JN)

Preparation and evaluation of surface-bonded tricationic ionic liquid silica as stationary phases for high-performance liquid chromatography.

PubMed

Qiao, Lizhen; Shi, Xianzhe; Lu, Xin; Xu, Guowang

2015-05-29

Two tricationic ionic liquids were prepared and then bonded onto the surface of supporting silica materials through "thiol-ene" click chemistry as new stationary phases for high-performance liquid chromatography. The obtained columns of tricationic ionic liquids were evaluated respectively in the reversed-phase liquid chromatography (RPLC) mode and hydrophilic interaction liquid chromatography (HILIC) mode, and possess ideal column efficiency of 80,000 plates/m in the RPLC mode with naphthalene as the test solute. The tricationic ionic liquid stationary phases exhibit good hydrophobic and shape selectivity to hydrophobic compounds, and RPLC retention behavior with multiple interactions. In the HILIC mode, the retention and selectivity were evaluated through the efficient separation of nucleosides and bases as well as flavonoids, and the typical HILIC retention behavior was demonstrated by investigating retention changes of hydrophilic solutes with water volume fraction in mobile phase. The results show that the tricationic ionic liquid columns possess great prospect for applications in analysis of hydrophobic and hydrophilic samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Micro-polarimeter for high performance liquid chromatography

DOEpatents

Yeung, Edward E.; Steenhoek, Larry E.; Woodruff, Steven D.; Kuo, Jeng-Chung

1985-01-01

A micro-polarimeter interfaced with a system for high performance liquid chromatography, for quantitatively analyzing micro and trace amounts of optically active organic molecules, particularly carbohydrates. A flow cell with a narrow bore is connected to a high performance liquid chromatography system. Thin, low birefringence cell windows cover opposite ends of the bore. A focused and polarized laser beam is directed along the longitudinal axis of the bore as an eluent containing the organic molecules is pumped through the cell. The beam is modulated by air gap Faraday rotators for phase sensitive detection to enhance the signal to noise ratio. An analyzer records the beams's direction of polarization after it passes through the cell. Calibration of the liquid chromatography system allows determination of the quantity of organic molecules present from a determination of the degree to which the polarized beam is rotated when it passes through the eluent.

Highly sensitive reversed-phase high-performance liquid chromatography assay for the detection of Tamm-Horsfall protein in human urine.

PubMed

Akimoto, Masaru; Hokazono, Eisaku; Ota, Eri; Tateishi, Takiko; Kayamori, Yuzo

2016-01-01

Tamm-Horsfall protein (also known as uromodulin) is the most abundant urinary protein in healthy individuals. Since initially characterized by Tamm and Horsfall, the amount of urinary excretion and structural mutations of Tamm-Horsfall protein is associated with kidney diseases. However, currently available assays for Tamm-Horsfall protein, which are mainly enzyme-linked immunosorbent assay-based, suffer from poor reproducibility and might give false negative results. We developed a novel, quantitative assay for Tamm-Horsfall protein using reversed-phase high-performance liquid chromatography. A precipitation pretreatment avoided urine matrix interference and excessive sample dilution. High-performance liquid chromatography optimization based on polarity allowed excellent separation of Tamm-Horsfall protein from other major urine components. Our method exhibited high precision (based on the relative standard deviations of intraday [≤2.77%] and interday [≤5.35%] repetitions). The Tamm-Horsfall protein recovery rate was 100.0-104.2%. The mean Tamm-Horsfall protein concentration in 25 healthy individuals was 31.6 ± 18.8 mg/g creatinine. There was a strong correlation between data obtained by high-performance liquid chromatography and enzyme-linked immunosorbent assay (r = 0.906), but enzyme-linked immunosorbent assay values tended to be lower than high-performance liquid chromatography values at low Tamm-Horsfall protein concentrations. The high sensitivity and reproducibility of our Tamm-Horsfall protein assay will reduce the number of false negative results of the sample compared with enzyme-linked immunosorbent assay. Moreover, our method is superior to other high-performance liquid chromatography methods, and a simple protocol will facilitate further research on the physiological role of Tamm-Horsfall protein. © The Author(s) 2015.

Haemoglobin variants may cause significant differences in haemoglobin A1c as measured by high-performance liquid chromatography and enzymatic methods in diabetic patients: a cross-sectional study.

PubMed

Otabe, Shuichi; Nakayama, Hitomi; Ohki, Tsuyoshi; Soejima, Eri; Tajiri, Yuji; Yamada, Kentaro

2017-07-01

Background We aimed to determine whether the discrepancy between haemoglobin A1c values determined by high-performance liquid chromatography and enzymatic haemoglobin A1c measurements in diabetic patients was clinically relevant. Methods We randomly recruited 1421 outpatients undergoing diabetic treatment and follow-up who underwent at least three haemoglobin A1c measurements between April 2014 and March 2015 at our clinic. In 6369 samples, haemoglobin A1c was simultaneously measured by HA-8160 and MetaboLead (enzymatic assay), and the values were compared. Results haemoglobin A1c measurements by high-performance liquid chromatography and enzymatic assay were strongly correlated (correlation coefficient: 0.9828, linear approximation curve y = 0.9986x - 0.2507). Mean haemoglobin A1c (6.8 ± 1.0%) measured by high-performance liquid chromatography was significantly higher than that measured by enzymatic assay (6.5 ± 1.0%, P < 0.0001). During the sample processing, four (0.3%) subjects presented consistently lower haemoglobin A1c values (<0.7%) by high-performance liquid chromatography than those from enzymatic assay. Of these, three had Hb Toranomon [β112 (G14) Cys→Trp]. The fourth had Hb Ube-2 [α68 (E17) Asn→Asp]. One other subject presented consistently higher haemoglobin A1c values (>1%) by high-performance liquid chromatography than those from enzymatic assay and was diagnosed with a -77 (T > C) mutation in the δ-globin gene. These unrelated asymptomatic subjects had normal erythrocyte profiles, without anaemia. Conclusions We showed that haemoglobin A1c values measured by high-performance liquid chromatography were significantly higher than those measured by enzymatic assay in diabetic subjects. However, when an oversized deviation (>0.7%) between glycaemic control status and haemoglobin A1c is apparent, clinicians should check the methods used to measure haemoglobin A1c and consider the possible presence of a haemoglobin variant.

Quantification of Quercetin and Rutin from Benincasa hispida Seeds and Carissa Congesta Roots by High-performance Thin Layer Chromatography and High-performance Liquid Chromatography

PubMed Central

Doshi, Gaurav Mahesh; Une, Hemant Devidas

2016-01-01

Objective: In Indian Ayurvedic system, Benincasa hispida (BH) and Carissa congesta (CC) are well-known plants used for major and minor ailments. BH has been regarded as Kushmanda, whereas CC has been used in immune-related disorders of the human system. Quercetin and rutin identified from the vast plethora of plant extracts have proved to possess ethnopharmacological relevance. Materials and Methods: In present studies, we have determined quercetin and rutin in terms of percentage in BH seeds and CC roots by high-performance thin layer chromatography (HPTLC) and high-performance liquid chromatography (HPLC). After extraction and phytochemical screening, the extracts were subjected to quantification for the presence of quercetin and rutin by HPTLC and HPLC. Results: HPTLC showed quercetin as 44.60, 27.13% and rutin as 32.00, 36.31% w/w, whereas HPLC revealed quercetin as 34.00, 35.00% and rutin as 21.99, 45.03% w/v in BH and CC extracts, respectively. Conclusion: The BH and CC extracts have elucidated peaks that were corresponding with standard peaks on undertaking chromatographic studies. SUMMARY Quercetin and rutin are isolated from BH seeds and CC roots by High Performance. Thin Layer Chromatography and High Performance Liquid Chromatography. HPTLC revealed presence of quercetin as 44.60, 27.13 % and rutin as 32.00, 36.31 % w/w. HPLC revealed presence of quercetin as 34.00, 35.00 % and rutin as 21.99, 45.03 % w/v. Abbreviation Used: HPTLC: High Performance Thin Layer Chromatography; HPLC: High Pressure Liquid Chromatography, UV: Ultraviolet, CC: Carissa congesta, BH: Benincasa hispida PMID:26941534

High-performance liquid chromatography of oligoguanylates at high pH

NASA Technical Reports Server (NTRS)

Stribling, R.; Deamer, D. (Principal Investigator)

1991-01-01

Because of the stable self-structures formed by oligomers of guanosine, standard high-performance liquid chromatography techniques for oligonucleotide fractionation are not applicable. Previously, oligoguanylate separations have been carried out at pH 12 using RPC-5 as the packing material. While RPC-5 provides excellent separations, there are several limitations, including the lack of a commercially available source. This report describes a new anion-exchange high-performance liquid chromatography method using HEMA-IEC BIO Q, which successfully separates different forms of the guanosine monomer as well as longer oligoguanylates. The reproducibility and stability at high pH suggests a versatile role for this material.

Multichannel Detection in High-Performance Liquid Chromatography.

ERIC Educational Resources Information Center

Miller, James C.; And Others

1982-01-01

A linear photodiode array is used as the photodetector element in a new ultraviolet-visible detection system for high-performance liquid chromatography (HPLC). Using a computer network, the system processes eight different chromatographic signals simultaneously in real-time and acquires spectra manually/automatically. Applications in fast HPLC…

Mallow carotenoids determined by high-performance liquid chromatography

USDA-ARS?s Scientific Manuscript database

Mallow (corchorus olitorius) is a green vegetable, which is widely consumed either fresh or dry by Middle East population. This study was carried out to determine the contents of major carotenoids quantitatively in mallow, by using a High Performance Liquid Chromatography (HPLC) equipped with a Bis...

High Performance Liquid Chromatography of Vitamin A: A Quantitative Determination.

ERIC Educational Resources Information Center

Bohman, Ove; And Others

1982-01-01

Experimental procedures are provided for the quantitative determination of Vitamin A (retinol) in food products by analytical liquid chromatography. Standard addition and calibration curve extraction methods are outlined. (SK)

An Efficient Protocol for Preparation of Gallic Acid from Terminalia bellirica (Gaertn.) Roxb by Combination of Macroporous Resin and Preparative High-Performance Liquid Chromatography.

PubMed

Zou, Denglang; Chen, Tao; Chen, Chen; Li, Hongmei; Liu, Yongling; Li, Yulin

2016-08-01

In this article, macroporous resin column chromatography and preparative high-performance liquid chromatography were applied for preparation of gallic acid from Terminalia bellirica (Gaertn.) Roxb. In the first step, six kinds of resins were investigated by adsorption and desorption tests and AB-8 macroporous resin was selected for the enrichment of gallic acid. As a result, 20 g of gallic acid at a purity of 71% could be separated from 100 g of crude extract in which the content of gallic acid was 16.7% and the recovery of gallic acid reached 85.0%. In the second step, preparative high-performance liquid chromatography was selected to purify gallic acid. As a result, 640 mg of gallic acid at a purity of 99.1% was obtained from 1 g of sample in 35 min. The results demonstrated that macroporous resin coupled with preparative high-performance liquid chromatography was suitable for preparation of gallic acid from T. bellirica (Gaertn.) Roxb. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

DETERMINATION OF CHLOROPHEONIS, NITROPHENOIS AND METHYLPHENOIS IN GROUND-WATER SAMPLES USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

EPA Science Inventory

A high performance liquid chromatography (HPLC) method was developed to quantitatively determine phenolic compounds and their isomers in aqueous samples. The HPLC method can analyze a mixture of 15 contaminants in the same analytical run with an analysis time of 25 minutes. The...

EXTRACTION AND QUANTITATIVE ANALYSIS OF ELEMENTAL SULFUR FROM SULFIDE MINERAL SURFACES BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY. (R826189)

EPA Science Inventory

A simple method for the quantitative determination of elemental sulfur on oxidized sulfide minerals is described. Extraction of elemental sulfur in perchloroethylene and subsequent analysis with high-performance liquid chromatography were used to ascertain the total elemental ...

Sugar Determination in Foods with a Radially Compressed High Performance Liquid Chromatography Column.

ERIC Educational Resources Information Center

Ondrus, Martin G.; And Others

1983-01-01

Advocates use of Waters Associates Radial Compression Separation System for high performance liquid chromatography. Discusses instrumentation and reagents, outlining procedure for analyzing various foods and discussing typical student data. Points out potential problems due to impurities and pump seal life. Suggests use of ribose as internal…

Simultaneous determination of estrogens and progestogens in honey using high performance liquid chromatography-tandem mass spectrometry

USDA-ARS?s Scientific Manuscript database

This work describes the development and validation of a method for the simultaneous determination of 13 estrogens and progestogens in honey by high performance liquid chromatography-tandem mass spectrometry. The target compounds were preconcentrated by solid phase extraction. Pretreatment variables ...

Quantification of Tea Flavonoids by High Performance Liquid Chromatography

ERIC Educational Resources Information Center

Freeman, Jessica D.; Niemeyer, Emily D.

2008-01-01

We have developed a laboratory experiment that uses high performance liquid chromatography (HPLC) to quantify flavonoid levels in a variety of commercial teas. Specifically, this experiment analyzes a group of flavonoids known as catechins, plant-derived polyphenolic compounds commonly found in many foods and beverages, including green and black…

Going Beyond, Going Further: An Inexpensive Experiment for the Introduction of High Performance Liquid Chromatography.

ERIC Educational Resources Information Center

Bidlingmeyer, Brian A.; Warren, F. Vincent, Jr.

1984-01-01

Background information, materials needed, laboratory procedures, and typical results are provided for five high performance liquid chromatography experiments (three isocratic and two step gradient separations). Suggestions for further experimentation are also provided, including quantitative determinations and separation of charged solutes. (JN)

DETERMINATION OF CHLOROPHENOLS, NITROPHENOLS, AND METHYLPHENOLS IN GROUND-WATER SAMPLES USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

EPA Science Inventory

A high performance liquid chromatography (HPLC) method was developed to quantitatively determine phenolic compounds and their isomers in aqueous samples. The HPLC method can analyze a mixture of 15 contaminants in the same analytical run with an analysis time of 25 minutes. The...

Characterization of phenolic amides from cortex lycii by ultra high-performance liquid chromatography coupled with LTQ-Orbitrap mass spectrometry

USDA-ARS?s Scientific Manuscript database

High performance liquid chromatography (UPLC) and flow injection electrospray ionization with ion trap mass spectrometry (FIMS) fingerprints combined with the principal component analysis (PCA) were examined for their potential in differentiating commercial organic and conventional sage samples. The...

Coupling nanoliter high-performance liquid chromatography to inductively coupled plasma mass spectrometry for arsenic speciation.

PubMed

Cheng, Heyong; Shen, Lihuan; Liu, Jinhua; Xu, Zigang; Wang, Yuanchao

2018-04-01

Nanoliter high-performance liquid chromatography shows low consumption of solvents and samples, offering one of the best choices for arsenic speciation in precious samples in combination with inuctively coupled plasma mass spectrometry. A systematic investigation on coupling nanoliter high-performance liquid chromatography to inductively coupled plasma mass spectrometry from instrument design to injected sample volume and mobile phase was performed in this study. Nanoflow mobile phase was delivered by flow splitting using a conventional high-pressure pump with reuse of mobile phase waste. Dead volume was minimized to 60 nL for the sheathless interface based on the previously developed nanonebulizer. Capillary columns for nanoliter high-performance liquid chromatography were found to be sensitive to sample loading volume. An apparent difference was also found between the mobile phases for nanoliter and conventional high-performance liquid chromatography. Baseline separation of arsenite, arsenate, monomethylarsenic, and dimethylarsenic was achieved within 11 min on a 15 cm C 18 capillary column and within 12 min on a 25 cm strong anion exchange column. Detection limits of 0.9-1.8 μg/L were obtained with precisions variable in the range of 1.6-4.2%. A good agreement between determined and certified values of a certified reference material of human urine (GBW 09115) validated its accuracy along with good recoveries (87-102%). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Screening, separation, and evaluation of xanthine oxidase inhibitors from Paeonia lactiflora using chromatography combined with a multi-mode microplate reader.

PubMed

Wang, Jing; Shi, Dongfang; Zheng, Meizhu; Ma, Bing; Cui, Jing; Liu, Chunming; Liu, Chengyu

2017-11-01

Natural products have become one of the most important resources for discovering novel xanthine oxidase inhibitors, which are commonly employed in the treatment of hyperuricemia and gout. However, to date, few reports exist regarding the use of monoterpene glycosides as xanthine oxidase inhibitors. Thus, we herein report the use of ultrafiltration coupled with liquid chromatography in the screening of monoterpene glycoside xanthine oxidase inhibitors from the extract of Paeonia lactiflora (P. lactiflora), and both high-performance counter-current chromatography and medium-pressure liquid chromatography were employed to separate the main constituents. Furthermore, the xanthine oxidase inhibitory activities and the mechanisms of inhibition of the isolated compounds were evaluated using a multi-mode microplate reader by Molecular Devices. As a result, three monoterpene glycosides were separated by combined high-performance counter-current chromatography and medium-pressure liquid chromatography in purities of 90.4, 98.0, and 86.3%, as determined by liquid chromatography. These three compounds were identified as albiflorin, paeoniflorin, and 1-O-β-ᴅ-glucopyranosyl-8-O-benzoylpaeonisuffrone by electrospray ionization tandem mass spectrometry, and albiflorin and paeoniflorin were screened as potential xanthine oxidase inhibitors by ultrafiltration with liquid chromatography. The evaluation results of xanthine oxidase inhibitory activity corresponded with the screening results, as only albiflorin and paeoniflorin exhibited xanthine oxidase inhibitory activity. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Phenolic composition of pomegranate peel extracts using an liquid chromatography-mass spectrometry approach with silica hydride columns.

PubMed

Young, Joshua E; Pan, Zhongli; Teh, Hui Ean; Menon, Veena; Modereger, Brent; Pesek, Joseph J; Matyska, Maria T; Dao, Lan; Takeoka, Gary

2017-04-01

The peels of different pomegranate cultivars (Molla Nepes, Parfianka, Purple Heart, Wonderful and Vkunsyi) were compared in terms of phenolic composition and total phenolics. Analyses were performed on two silica hydride based stationary phases: phenyl and undecanoic acid columns. Quantitation was accomplished by developing a liquid chromatography with mass spectrometry approach for separating different phenolic analytes, initially in the form of reference standards and then with pomegranate extracts. The high-performance liquid chromatography columns used in the separations had the ability to retain a wide polarity range of phenolic analytes, as well as offering beneficial secondary selectivity mechanisms for resolving the isobaric compounds, catechin and epicatechin. The Vkunsyi peel extract had the highest concentration of phenolics (as determined by liquid chromatography with mass spectrometry) and was the only cultivar to contain the important compound punicalagin. The liquid chromatography with mass spectrometry data were compared to the standard total phenolics content as determined by using the Folin-Ciocalteu assay. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simple high-performance liquid chromatography method for formaldehyde determination in human tissue through derivatization with 2,4-dinitrophenylhydrazine.

PubMed

Yilmaz, Bilal; Asci, Ali; Kucukoglu, Kaan; Albayrak, Mevlut

2016-08-01

A simple high-performance liquid chromatography method has been developed for the determination of formaldehyde in human tissue. FA Formaldehyde was derivatized with 2,4-dinitrophenylhydrazine. It was extracted from human tissue with ethyl acetate by liquid-liquid extraction and analyzed by high-performance liquid chromatography. The calibration curve was linear in the concentration range of 5.0-200 μg/mL. Intra- and interday precision values for formaldehyde in tissue were <6.9%, and accuracy (relative error) was better than 6.5%. The extraction recoveries of formaldehyde from human tissue were between 88 and 98%. The limits of detection and quantification of formaldehyde were 1.5 and 5.0 μg/mL, respectively. Also, this assay was applied to liver samples taken from a biopsy material. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparative Isolation and Purification of Flavone C-Glycosides from the Leaves of Ficus microcarpa L. f by Medium-Pressure Liquid Chromatography, High-Speed Countercurrent Chromatography, and Preparative Liquid Chromatography

PubMed Central

Wang, Xiaohong; Liang, Yong; Zhu, Licai; Xie, Huichun; Li, Hang; He, Junting; Pan, Man; Zhang, Tianyou; Ito, Yoichiro

2009-01-01

Combined with medium-pressure liquid chromatography (MPLC) and preparative high-performance liquid chromatography (perp-HPLC), high-speed countercurrent chromatography (HSCCC) was applied for separation and purification of flavone C-glycosides from the crude extract of leaves of Ficus microcarpae L. f. HSCCC separation was performed on a two-phase solvent system composed of methyl tert- butyl ether - ethyl acetate – 1-butanol – acetonitrile – 0.1% aqueous trifluoroacetic acid at a volume ratio of 1:3:1:1:5. Partially resolved peak fractions from HSCCC separation were further purified by preparative HPLC. Four well-separated compounds were obtained and their purities were determined by HPLC. The purities of these peaks were 97.28%, 97.20%, 92.23%, and 98.40%.. These peaks were characterized by ESI-MSn. According to the reference, they were identified as orientin (peak I), isovitexin-3″-O-glucopyranoside (peak II), isovitexin (peak III), and vitexin (peak IV), yielded 1.2 mg, 4.5 mg, 3.3 mg, and 1.8 mg, respectively. PMID:20190866

75 FR 38156 - Small Business Size Standards: Waiver of the Nonmanufacturer Rule

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-01

... Systems (CS-MS), High Performance Liquid Chromatography (HPLC) Systems, Gas Chromatography Mass... Chromatography (HPLC) Systems, Gas Chromatography Mass Spectrometry (GC-MS) Systems, and, Inductively Coupled...

Classification of cultivation locations of Panax quinquefolius L samples using high performance liquid chromatography-electrospray ionization mass spectrometry and chemometric analysis

USDA-ARS?s Scientific Manuscript database

Panax quinquefolius L (P. quinquefolius L) samples grown in the United States and China were analyzed with high performance liquid chromatography-mass spectrometry (HPLC—MS). Prior to classification, the two-way datasets were subjected to pretreatment including baseline correction and retention tim...

Classification of cultivation locations of panax quinquefolius L samples using high performance liquid chromatography-electrospray ionization mass spectrometry and chemometric analysis

USDA-ARS?s Scientific Manuscript database

Panax quinquefolius L (P. quinquefolius L) samples grown in the United States and China were analyzed with high performance liquid chromatography-mass spectrometry (HPLC—MS). Prior to classification, the two-way datasets were subjected to pretreatment including baseline correction and retention ti...

Extraction and Purification of Glucoraphanin by Preparative High-Performance Liquid Chromatography (HPLC)

ERIC Educational Resources Information Center

Lee, Iris; Boyce, Mary C.

2011-01-01

A student activity that focuses on the isolation of glucoraphanin from broccoli using preparative high-performance liquid chromatography (HPLC) is presented here. Glucoraphanin is a glucosinolate, whose byproducts are known to possess anticancer properties. It is present naturally at high levels in broccoli and other "Brassica" vegetables. This…

An Advanced, Interactive, High-Performance Liquid Chromatography Simulator and Instructor Resources

ERIC Educational Resources Information Center

Boswell, Paul G.; Stoll, Dwight R.; Carr, Peter W.; Nagel, Megan L.; Vitha, Mark F.; Mabbott, Gary A.

2013-01-01

High-performance liquid chromatography (HPLC) simulation software has long been recognized as an effective educational tool, yet many of the existing HPLC simulators are either too expensive, outdated, or lack many important features necessary to make them widely useful for educational purposes. Here, a free, open-source HPLC simulator is…

Determination of citrus limonoid glucosides by high performance liquid chromatography coupled to post-column reaction with Ehrlich’s Reagent

USDA-ARS?s Scientific Manuscript database

A method for the identification and quantification of citrus limonoid glucosides in juices based upon high performance liquid chromatography (HPLC) separation coupled to post-column reaction with Ehrlichs’s reagent has been developed. This method utilizes a phenyl stationary phase and an isocratic ...

Constructing a LabVIEW-Controlled High-Performance Liquid Chromatography (HPLC) System: An Undergraduate Instrumental Methods Exercise

ERIC Educational Resources Information Center

Smith, Eugene T.; Hill, Marc

2011-01-01

In this laboratory exercise, students develop a LabVIEW-controlled high-performance liquid chromatography system utilizing a data acquisition device, two pumps, a detector, and fraction collector. The programming experience involves a variety of methods for interface communication, including serial control, analog-to-digital conversion, and…

Using reversed phase high performance liquid chromatography to study the complexation of anthocyanins with β-cyclodextrin

NASA Astrophysics Data System (ADS)

Deineka, V. I.; Lapshova, M. S.; Deineka, L. A.

2014-06-01

It is shown by means of reversed phase high performance liquid chromatography (RP HPLC) with mobile phases containing additions of β-cyclodextrin that 5-glucosides of cyanidin and pelargonidin form stronger inclusion complexes than 3-glucosides; this is explained by the steric interference of the glucoside radical.

Determination and removal of antibiotics in secondary effluent using a horizontal subsurface flow constructed wetland.

PubMed

Zhang, Chunhui; Ning, Ke; Zhang, Wenwen; Guo, Yuanjie; Chen, Jun; Liang, Chen

2013-04-01

Increased attention is currently being directed towards the potential negative effects of antibiotics and other PPCPs discharged into the aquatic environment via municipal WWTP secondary effluents. A number of analytical methods, such as high performance liquid chromatography technologies, including a high performance liquid chromatography-fluorescence method (HPLC-FLD), high performance liquid chromatography-UV detection method (HPLC-UV) and high performance liquid chromatography-mass spectrometry method (HPLC-MS), have been suggested as determination technologies for antibiotic residues in water. In this study, we implement a HPLC-MS/MS combined method to detect and analyze antibiotics in WWTP secondary effluent and apply a horizontal subsurface flow constructed wetland (CW) as an advanced wastewater treatment for removing antibiotics in the WWTP secondary effluent. The results show that there were 2 macrolides, 2 quinolones and 5 sulfas in WWTP secondary effluent among all the 22 antibiotics considered. After the CW advanced treatment, the concentration removal efficiencies and removal loads of 9 antibiotics were 53-100% and 0.004-0.7307 μg m(-2) per day, respectively.

Two-way and three-way approaches to ultra high performance liquid chromatography-photodiode array dataset for the quantitative resolution of a two-component mixture containing ciprofloxacin and ornidazole.

PubMed

Dinç, Erdal; Ertekin, Zehra Ceren; Büker, Eda

2016-09-01

Two-way and three-way calibration models were applied to ultra high performance liquid chromatography with photodiode array data with coeluted peaks in the same wavelength and time regions for the simultaneous quantitation of ciprofloxacin and ornidazole in tablets. The chromatographic data cube (tensor) was obtained by recording chromatographic spectra of the standard and sample solutions containing ciprofloxacin and ornidazole with sulfadiazine as an internal standard as a function of time and wavelength. Parallel factor analysis and trilinear partial least squares were used as three-way calibrations for the decomposition of the tensor, whereas three-way unfolded partial least squares was applied as a two-way calibration to the unfolded dataset obtained from the data array of ultra high performance liquid chromatography with photodiode array detection. The validity and ability of two-way and three-way analysis methods were tested by analyzing validation samples: synthetic mixture, interday and intraday samples, and standard addition samples. Results obtained from two-way and three-way calibrations were compared to those provided by traditional ultra high performance liquid chromatography. The proposed methods, parallel factor analysis, trilinear partial least squares, unfolded partial least squares, and traditional ultra high performance liquid chromatography were successfully applied to the quantitative estimation of the solid dosage form containing ciprofloxacin and ornidazole. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Separation of flavonol-2-O-glycosides from Calendula officinalis and Sambucus nigra by high-performance liquid and micellar electrokinetic capillary chromatography.

PubMed

Pietta, P; Bruno, A; Mauri, P; Rava, A

1992-02-28

Calendula officinalis and Sambucus nigra flowers were analysed by reversed-phase high-performance liquid chromatography (RP-HPLC) and micellar electrokinetic capillary chromatography (MECC). RP-HPLC was performed on C8 Aquapore RP 300 columns with eluents containing 2-propanol and tetrahydrofuran. MECC was carried out on a 72-cm fused-silica capillary using sodium dodecyl sulphate and sodium borate (pH 8.3) as the running buffer. The results obtained by these techniques are compared.

Analysis of lignans in Magnoliae Flos by turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry.

PubMed

Zhou, Xuan; Chen, Cen; Ye, Xiaolan; Song, Fenyun; Fan, Guorong; Wu, Fuhai

2016-04-01

In this study, a method coupling turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry was developed for analyzing the lignans in Magnoliae Flos. By the online pretreatment of turbulent flow chromatography solid-phase extraction, the impurities removal and analytes concentration were automatically processed, and the lignans were separated rapidly and well. Seven lignans of Magnoliae Flos including epieudesmin, magnolin, 1-irioresinol-B-dimethyl ether, epi-magnolin, fargesin aschantin, and demethoxyaschantin were identified by comparing their retention behavior, UV spectra, and mass spectra with those of reference substances or literature data. The developed method was validated, and the good results showed that the method was not only automatic and rapid, but also accurate and reliable. The turbulent flow chromatography with online solid-phase extraction and high-performance liquid chromatography with tandem mass spectrometry method holds a high potential to become an effective method for the quality control of lignans in Magnoliae Flos and a useful tool for the analysis of other complex mixtures. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Analysis of selected herbicide metabolites in surface and ground water of the United States

USGS Publications Warehouse

Scribner, E.A.; Thurman, E.M.; Zimmerman, L.R.

2000-01-01

One of the primary goals of the US Geological Survey (USGS) Laboratory in Lawrence, Kansas, is to develop analytical methods for the analysis of herbicide metabolites in surface and ground water that are vital to the study of herbicide fate and degradation pathways in the environment. Methods to measure metabolite concentrations from three major classes of herbicides - triazine, chloroacetanilide and phenyl-urea - have been developed. Methods for triazine metabolite detection cover nine compounds: six compounds are detected by gas chromatography/mass spectrometry; one is detected by high-performance liquid chromatography with diode-array detection; and eight are detected by liquid chromatography/mass spectrometry. Two metabolites of the chloroacetanilide herbicides - ethane sulfonic acid and oxanilic acid - are detected by high-performance liquid chromatography with diode-array detection and liquid chromatography/mass spectrometry. Alachlor ethane sulfonic acid also has been detected by solid-phase extraction and enzyme-linked immunosorbent assay. Six phenylurea metabolites are all detected by liquid chromatography/mass spectrometry; four of the six metabolites also are detected by gas chromatography/mass spectrometry. Additionally, surveys of herbicides and their metabolites in surface water, ground water, lakes, reservoirs, and rainfall have been conducted through the USGS laboratory in Lawrence. These surveys have been useful in determining herbicide and metabolite occurrence and temporal distribution and have shown that metabolites may be useful in evaluation of non-point-source contamination. Copyright (C) 2000 Elsevier Science B.V.

Determination of diacylhydrazines-type insect growth regulator JS-118 residues in cabbage and soil by high performance liquid chromatography with DAD detection.

PubMed

Hu, J-Y; Deng, Z-B; Qin, D-M

2009-12-01

JS-118 is a diacylhydrazines-type insect growth regulator used extensively in China now. An analytical method for residues determination of JS-118 in cabbage and soil samples by high performance liquid chromatography with DAD detection was established and optimized. Primary secondary amine solid phase extraction cartridge was used for sample preparation. Mean recoveries for the analyte ranged from 96.6% to 107.0% with CV value less than 4.7%. The limit of quantification is 0.01 mg/kg. Direct confirmation of JS-118 residues in samples was realized by high performance liquid chromatography-mass spectrometry. The proposed method is simple, rapid and reliable to perform and could be utilized for monitoring of pesticides residues.

Recent advances in liquid-phase separations for clinical metabolomics.

PubMed

Kohler, Isabelle; Giera, Martin

2017-01-01

Over the last decades, several technological improvements have been achieved in liquid-based separation techniques, notably, with the advent of fully porous sub-2 μm particles and superficially porous sub-3 μm particles, the comeback of supercritical fluid chromatography, and the development of alternative chromatographic modes such as hydrophilic interaction chromatography. Combined with mass spectrometry, these techniques have demonstrated their added value, substantially increasing separation efficiency, selectivity, and speed of analysis. These benefits are essential in modern clinical metabolomics typically involving the study of large-scale sample cohorts and the analysis of thousands of metabolites showing extensive differences in physicochemical properties. This review presents a brief overview of the recent developments in liquid-phase separation sciences in the context of clinical metabolomics, focusing on increased throughput as well as metabolite coverage. Relevant metabolomics applications highlighting the benefits of ultra-high performance liquid chromatography, core-shell technology, high-temperature liquid chromatography, capillary electrophoresis, supercritical fluid chromatography, and hydrophilic interaction chromatography are discussed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ruggedness testing and validation of a practical analytical method for > 100 veterinary drug residues in bovine muscle by ultrahigh performance liquid chromatography – tandem mass spectrometry

USDA-ARS?s Scientific Manuscript database

In this study, optimization, extension, and validation of a streamlined, qualitative and quantitative multiclass, multiresidue method was conducted to monitor great than100 veterinary drug residues in meat using ultrahigh-performance liquid chromatography – tandem mass spectrometry (UHPLC-MS/MS). I...

Profiling the indole alkaloids in yohimbe bark with ultra-performance liquid chromatography coupled with ion mobility quadrupole time-of-flight mass spectrometry

USDA-ARS?s Scientific Manuscript database

An ultra-high performance liquid chromatography-ion mobility- quadrupole time-of-flight mass spectrometry (UHPLC-IM-QTOF-MS) method was developed for profiling the indole alkaloids in yohimbe bark. Many indole alkaloids with the yohimbine core structure, plus methylated, oxidized, and reduced speci...

Simultaneous Determination of Caffeine and Vitamin B6 in Energy Drinks by High-Performance Liquid Chromatography (HPLC)

ERIC Educational Resources Information Center

Leacock, Rachel E.; Stankus, John J.; Davis, Julian M.

2011-01-01

A high-performance liquid chromatography experiment to determine the concentration of caffeine and vitamin B6 in sports energy drinks has been developed. This laboratory activity, which is appropriate for an upper-level instrumental analysis course, illustrates the standard addition method and simultaneous determination of two species. (Contains 1…

Rapid qualitative and quantitative analysis of proanthocyanidin oligomers and polymers by ultra-performance liquid chromatography – tandem mass spectrometry (UPLC-MS/MS)

USDA-ARS?s Scientific Manuscript database

We developed a rapid method with ultra-performance liquid chromatography – tandem mass spectrometry (UPLC-MS/MS) for the qualitative and quantitative analysis of plant proanthocyanidins (PAs) directly from crude plant extracts. The method utilizes a range of cone voltages to achieve the depolymeriza...

Utilization of high performance liquid chromatography coupled to tandem mass spectrometry for characterization of 8-O-methylbostrycoidin production by species of the fungus Fusarium

USDA-ARS?s Scientific Manuscript database

The pigment, 8-O-methylbostrycoidin is a polyketide metabolite produced by multiple species of the fungus Fusarium that infects plant crops, including maize. A technique was developed for the analysis of 8-O-methylbostrycoidin by high performance liquid chromatography coupled to electrospray ionizat...

Determination of low molecular weight thiols using monobromobimane fluorescent labeling and high-performance liquid chromatography

NASA Technical Reports Server (NTRS)

Fahey, Robert C.; Newton, Gerald L.

1988-01-01

Methods are described for the preparation and high-performance liquid chromatography (HPLC) analysis of monobromobimane derivatives of low molecular weight thiols in extracts of biological samples. Typical problems encountered in the development and application of these methods are discussed. Analysis of mung bean extract is used as an example.

Comparative oxidation state specific analysis of arsenic species by high-performance liquid chromatography-inductively coupled-mass spectrometry and hydride generation-cryotrapping-atomic absorption spectrometry

EPA Science Inventory

The formation of methylarsonous acid (MAsIII) and dimethylarsinous acid (DMAsIII) in the course of inorganic arsenic (iAs) metabolism plays an important role in the adverse effects of chronic exposure to iAs. High-performance liquid chromatography-inductively coupled plasma-mass ...

Determination of Aspartame, Caffeine, Saccharin, and Benzoic Acid in Beverages by High Performance Liquid Chromatography.

ERIC Educational Resources Information Center

Delaney, Michael F.; And Others

1985-01-01

Describes a simple and reliable new quantitative analysis experiment using liquid chromatography for the determinaiton of caffeine, saccharin, and sodium benzoate in beverages. Background information, procedures used, and typical results obtained are provided. (JN)

Identification, characterization, and high-performance liquid chromatography quantification of process-related impurities in vonoprazan fumarate.

PubMed

Liu, Lei; Cao, Na; Ma, Xingling; Xiong, Kaihe; Sun, Lili; Zou, Qiaogen

2016-04-01

High-performance liquid chromatography analysis of vonoprazan fumarate, a novel proton pump inhibitor drug revealed six impurities. These were identified by liquid chromatography with mass spectrometry. Further, the structures of the impurities were confirmed by synthesis followed by characterization by mass spectrometry, NMR spectroscopy, and infrared spectroscopy. On the basis of these data and knowledge of the synthetic scheme of vonoprazan fumarate, the previously unknown impurity was identified as 1-[5-(2-fluorophenyl)-1-(pyridin-3-ylsulfonyl)-1H-pyrrol-3-yl]-N-methyldimethylamine, which is a new compound. The possible mechanisms by which these impurities were formed were also discussed. A high-performance liquid chromatography method was optimized in order to separate, selectively detect, and quantify all process-related impurities of vonoprazan fumarate. The presented method has been validated in terms of linearity, limits of detection, and quantification, and response factors and, therefore, is highly suitable for routine analysis of vonoprazan fumarate related substances as well as stability studies. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comprehensive quantitative analysis of Chinese patent drug YinHuang drop pill by ultra high-performance liquid chromatography quadrupole time of flight mass spectrometry.

PubMed

Wong, Tin-Long; An, Ya-Qi; Yan, Bing-Chao; Yue, Rui-Qi; Zhang, Tian-Bo; Ho, Hing-Man; Ren, Tian-Jing; Fung, Hau-Yee; Ma, Dik-Lung; Leung, Chung-Hang; Liu, Zhong-Liang; Pu, Jian-Xin; Han, Quan-Bin; Sun, Han-Dong

2016-06-05

YinHuang drop pill (YHDP) is a new preparation, derived from the traditional YinHuang (YH) decoction. Since drop pills are one of the newly developed forms of Chinese patent drugs, not much research has been done regarding the quality and efficacy. This study aims to establish a comprehensive quantitative analysis of the chemical profile of YHDP. ultra high-performance liquid chromatography quadrupole time of flight mass spectrometry (UHPLC-Q-TOF-MS/MS) was used to identify 34 non-sugar small molecules including 15 flavonoids, 9 phenolic acids, 5 saponins, 1 iridoid, and 4 iridoid glycosides in YHDP samples, and 26 of them were quantitatively determined. Sugar composition of YHDP in terms of fructose, glucose and sucrose was examined via a high performance liquid chromatography-evaporative light scattering detector on an amide column (HPLC-NH2P-ELSD). Macromolecules were examined by high performance gel permeation chromatography coupled with ELSD (HPGPC-ELSD). The content of the drop pill's skeleton component PEG-4000 was also quantified via ultra-high performance liquid chromatography coupled with charged aerosol detector (UHPLC-CAD). The results showed that up to 73% (w/w) of YHDP could be quantitatively determined. Small molecules accounted for approximately 5%, PEG-4000 represented 68%, while no sugars or macromolecules were found. Furthermore, YHDP showed no significant differences in terms of daily dosage, compared to YinHuang granules and YinHuang oral liquid; however, it has a higher small molecules content compared to YinHuang lozenge. Copyright © 2016 Elsevier B.V. All rights reserved.

Separation of four flavonol glycosides from Solanum rostratum Dunal using aqueous two-phase flotation followed by preparative high-performance liquid chromatography.

PubMed

Chang, Lin; Shao, Qian; Xi, Xingjun; Chu, Qiao; Wei, Yun

2017-02-01

Aqueous two-phase flotation followed by preparative high-performance liquid chromatography was used to separate four flavonol glycosides from Solanum rostratum Dunal. In the aqueous two-phase flotation section, the effects of sublation solvent, solution pH, (NH 4 ) 2 SO 4 concentration in aqueous solution, cosolvent, N 2 flow rate, flotation time, and volumes of the polyethylene glycol phase on the recovery were investigated in detail, and the optimal conditions were selected: 50 wt% polyethylene glycol 1000 ethanol solvent as the flotation solvent, pH 4, 350 g/L of (NH 4 ) 2 SO 4 concentration in aqueous phase, 40 mL/min of N 2 flow rate, 30 min of flotation time, 10.0 mL of flotation solvent volume, and two times. After aqueous two-phase flotation concentration, the flotation products were purified by preparative high-performance liquid chromatography. The purities of the final products A and B were 98.1 and 99.0%. Product B was the mixture of three compounds based on the analysis of high-performance liquid chromatography at the temperature of 10°C, while product A was hyperoside after the identification by nuclear magnetic resonance. Astragalin, 3'-O-methylquercetin 3-O-β-d-galactopyranoside, and 3'-O-methylquercetin 3-O-β-d-glucopyranoside were obtained with the purity of 93.8, 97.1, and 99.2%, respectively, after the further separation of product B using preparative high-performance liquid chromatography. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Normal-Phase Open Column versus Reversed-Phase High Performance Liquid Chromatography: Separation of Chlorophyll a and Chlorophyll b from their Diastereomers.

ERIC Educational Resources Information Center

Schaber, Peter M.

1985-01-01

Background information, procedures used, and typical results obtained are provided for an experiment involving the separation of chlorophyll a and chlorophyll b from their diastereomers. Reasons why the experiment can be easily integrated into most laboratory curricula where high-performance liquid chromatography capabilities exist are given. (JN)

Ultra-performance liquid chromatography tandem mass-spectrometry (uplc-ms/ms) for the rapid, simultaneous analysis of thiamin, riboflavin, flavin adenine dinucleotide, nicotinamide and pyridoxal in human milk

USDA-ARS?s Scientific Manuscript database

A novel, rapid and sensitive Ultra Performance Liquid-Chromatography tandem Mass-Spectrometry (UPLC-MS/MS) method for the simultaneous determination of several B-vitamins in human milk was developed. Resolution by retention time or multiple reaction monitoring (MRM) for thiamin, riboflavin, flavin a...

Comparison of high performance liquid chromatography and enzymatic analysis of soluble carbohydrates in loblolly pine

Treesearch

Patricia L. Faulkner; Michele M. Schoeneberger; Kim H. Ludovici

1993-01-01

Foliar tissue was collected from a field study designed to test impacts of atmospheric pollutants on loblolIy pine (Pinus taeda L.) seedlings. Standard enzymatic (ENZ) and high performance liquid chromatography (HPLC) methods were used to analyze the tissue for soluble sugars. A comparison of the methods revealed no significant diffennces in accuracy...

Ultramicroelectrode Sensors and Detectors. Considerations of the Stability, Sensitivity, Reproducibility, and Mechanism of Ion Transport in Gas Phase Chromatography and in High Performance Liquid Phase Chromatography

DTIC Science & Technology

1988-07-15

solvents were used. For high performance liquid chromatographic studies, the DNA bases thymine, adenine, cytocine, uracil, and guanine (Aldrich...this experiment. The DNA bases guanine, adenine, cytocine, uracil, and thymine were detected for a gradient elution of a mixture of the bases in a

Peptide profiling of Internet-obtained Cerebrolysin using high performance liquid chromatography - electrospray ionization ion trap and ultra high performance liquid chromatography - ion mobility - quadrupole time of flight mass spectrometry.

PubMed

Gevaert, Bert; D'Hondt, Matthias; Bracke, Nathalie; Yao, Han; Wynendaele, Evelien; Vissers, Johannes Petrus Cornelis; De Cecco, Martin; Claereboudt, Jan; De Spiegeleer, Bart

2015-09-01

Cerebrolysin, a parenteral peptide preparation produced by controlled digestion of porcine brain proteins, is an approved nootropic medicine in some countries. However, it is also easily and globally available on the Internet. Nevertheless, until now, its exact chemical composition was unknown. Using high performance liquid chromatography (HPLC) coupled to ion trap and ultra high performance liquid chromatography (UHPLC) coupled to quadrupole-ion mobility-time-of-flight mass spectrometry (Q-IM-TOF MS), combined with UniProt pig protein database search and PEAKS de novo sequencing, we identified 638 unique peptides in an Internet-obtained Cerebrolysin sample. The main components in this sample originate from tubulin alpha- and beta-chain, actin, and myelin basic protein. No fragments of known neurotrophic factors like glial cell-derived neurotrophic factor (GDNF), neurotrophin nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and ciliary neurotrophic factor (CNTF) were found, suggesting that the activities reported in the literature are likely the result of new, hitherto unknown cryptic peptides with nootropic properties. Copyright © 2015 John Wiley & Sons, Ltd.

Detection of AGXT bgene mutations by denaturing high-performance liquid chromatography for diagnosis of hyperoxaluria type 1.

PubMed

Pirulli, D; Giordano, M; Lessi, M; Spanò, A; Puzzer, D; Zezlina, S; Boniotto, M; Crovella, S; Florian, F; Marangella, M; Momigliano-Richiardi, P; Savoldi, S; Amoroso, A

2001-06-01

Primary hyperoxaluria type 1 is an autosomal recessive disorder of glyoxylate metabolism, caused by a deficiency of alanine:glyoxylate aminotransferase, which is encoded by a single copy gene (AGXT. The aim of this research was to standardize denaturing high-performance liquid chromatography, a new, sensitive, relatively inexpensive, and automated technique, for the detection of AGXT mutation. Denaturing high-performance liquid chromatography was used to analyze in blind the AGXT gene in 20 unrelated Italian patients with primary hyperoxaluria type I previously studied by other standard methods (single-strand conformation polymorphism analysis and direct sequencing) and 50 controls. Denaturing high-performance liquid chromatography allowed us to identify 13 mutations and the polymorphism at position 154 in exon I of the AGXT gene. Hence the method is more sensitive and less time consuming than single-strand conformation polymorphism analysis for the detection of AGXT mutations, thus representing a useful and reliable tool for detecting the mutations responsible for primary hyperoxaluria type 1. The new technology could also be helpful in the search for healthy carriers of AGXT mutations amongst family members and their partners, and for screening of AGXT polymorphisms in patients with nephrolithiasis and healthy populations.

High temperature-ultra performance liquid chromatography-mass spectrometry for the metabonomic analysis of Zucker rat urine.

PubMed

Gika, Helen G; Theodoridis, Georgios; Extance, Jon; Edge, Anthony M; Wilson, Ian D

2008-08-15

The applicability and potential of using elevated temperatures and sub 2-microm porous particles in chromatography for metabonomics/metabolomics was investigated using, for the first time, solvent temperatures higher than the boiling point of water (up to 180 degrees C) and thermal gradients to reduce the use of organic solvents. Ultra performance liquid chromatography, combined with mass spectrometry, was investigated for the global metabolite profiling of the plasma and urine of normal and Zucker (fa/fa) obese rats (a well established disease animal model). "Isobaric" high temperature chromatography, where the temperature and flow rate follow a gradient program, was developed and evaluated against a conventional organic solvent gradient. LC-MS data were first examined by established chromatographic criteria in order to evaluate the chromatographic performance and next were treated by special peak picking algorithms to allow the application of multivariate statistics. These studies showed that, for urine (but not plasma), chromatography at elevated temperatures provided better results than conventional reversed-phase LC with higher peak capacity and better peak asymmetry. From a systems biology point of view, better group clustering and separation was obtained with a larger number of variables of high importance when using high temperature-ultra performance liquid chromatography (HT-UPLC) compared to conventional solvent gradients.

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.

DNAPL Dissolution in Bedrock Fractures And Fracture Networks

DTIC Science & Technology

2011-06-01

were filtered through a 0.2 micron filter and then analyzed via ion chromatography ( Dionex DX-120, Sunnyvale, CA). An additional set of sorption...analyzed via ion chromatography ( Dionex DX-120, Sunnyvale, CA). The effluent pH was monitored periodically with pH test strips. Aqueous DHC...liquid EDTA ethylenediaminetetraacetic acid GC gas chromatograph HPLC high-performance liquid chromatography ISCO in situ chemical oxidation

Enantioselective separation of racemic juvenile hormone III by normal-phase high-performance liquid chromatography and preparation of [(2)H(3)]juvenile hormone III as an internal standard for liquid chromatography-mass spectrometry quantification.

PubMed

Ichikawa, Akio; Ono, Hiroshi; Furuta, Kenjiro; Shiotsuki, Takahiro; Shinoda, Tetsuro

2007-08-17

Juvenile hormone III (JH III) racemate was prepared from methyl (2E,6E)-farnesoate via epoxidation with 3-chloroperbenzoic acid (mCPBA). Enantioselective separation of JH III was conducted using normal-phase high-performance liquid chromatography (HPLC) on a chiral stationary phase. [(2)H(3)]Methyl (2E,6E)-farnesoate was also prepared from (2E,6E)-farnesoic acid and [(2)H(4)]methanol (methanol-d(4)) using 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and 4-dimethylaminopyridine (DMAP); the conjugated double bond underwent isomerization to some degree. Epoxidation of [(2)H(3)]methyl (2E,6E)-farnesoate with mCPBA gave a novel deuterium-substituted internal standard [(2)H(3)]JH III (JH III-d(3)). The standard curve was produced by linear regression using the peak area ratios of JH III and JH III-d(3) in liquid chromatography-mass spectrometry (LC-MS).

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

DTIC Science & Technology

2016-04-01

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

Simultaneous analysis of tert-butylhydroquinone, tert-butylquinone, butylated hydroxytoluene, 2-tert-butyl-4-hydroxyanisole, 3-tert-butyl-4-hydroxyanisole, α-tocopherol, γ-tocopherol, and δ-tocopherol in edible oils by normal-phase high performance liquid chromatography.

PubMed

Li, Jun; Bi, Yanlan; Sun, Shangde; Peng, Dan

2017-11-01

A normal-phase high performance liquid chromatography method for the simultaneous determination of tert-butylhydroquinone, tert-butylquinone, butylated hydroxytoluene, 2-tert-butyl-4-hydroxyanisole, 3-tert-butyl-4-hydroxyanisole, α-tocopherol, γ-tocopherol, and δ-tocopherol in edible oils was investigated. A silica column was used to separate the analytes with the gradient elution. An ultraviolet-visible detector was set at dual wavelengths mode (280 and 310nm). The column temperature was 30°C. The analytes were directly extracted with methanol. Results showed that the normal-phase high performance liquid chromatography method performed well with wide liner ranges (0.10∼500.00μg/mL, R 2 >0.9998), low limits of detection and quantitation (below 0.40 and 1.21μg/mL, respectively), and good recoveries (81.38∼102.34% in soybean oils and 83.03∼100.79% in lard, respectively). The reduction of tert-butylquinone caused by the reverse-phase high performance liquid chromatography during the injection was avoided with the current normal-phase method. The two isomers of butylated hydroxyanisole can also be separated with good resolution. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fuel Composition and Performance Analysis of Endothermically Heated Fuels for Pulse Detonation Engines

DTIC Science & Technology

2009-03-01

Waste heat from a pulse detonation engine (PDE) was extracted via concentric, counter flow heat exchangers to produce supercritical pyrolytic...mass spectrometry HLPC = High performance liquid chromatography NPT = National pipe thread PAH = Polycyclic aromatic hydrocarbon PDE = Pulse...Precision Liquid Chromatography (HPLC). The resulting “stressed” fuel showed a 29 shift to lower molecular weight compounds, as well as the production

Method 447.0 - Determination of Chlorophylls a and b and Identification of Other Pigments of Interest in Marine and Freshwater Algae Using High Performance Liquid Chromatography with Visible Wavelength Detection

EPA Science Inventory

This method provides a procedure for determination of chlorophylls a (chl a) and b (chl b) found in marine and freshwater phytoplankton. Reversed phase high performance liquid chromatography (HPLC) with detection at 440 nm is used to separate the pigments from a complex pigment ...

Chitin-coated Celite as an affinity adsorbent for high-performance liquid chromatography of lysozyme.

PubMed

Yamada, H; Fukumura, T; Ito, Y; Imoto, T

1985-04-01

Preparation of chitin-coated Celite as an affinity adsorbent for high-performance liquid chromatography of lysozymes and its application to separation of N-bromosuccinimide-oxidized lysozymes are described. By pH gradient elution, two diastereomers of oxindolealanine-62-lysozyme, delta 1-acetoxytryptophan-62-lysozyme (intermediate product in the reaction in acetate buffer), and native lysozyme were all separated within 40 min.

Rapid pretreatment and determination of bisphenol A in water samples based on vortex-assisted liquid-liquid microextraction followed by high-performance liquid chromatography with fluorescence detection.

PubMed

Yang, Xiao; Diao, Chun-Peng; Sun, Ai-Ling; Liu, Ren-Min

2014-10-01

A method for the rapid pretreatment and determination of bisphenol A in water samples based on vortex-assisted liquid-liquid microextraction followed by high-performance liquid chromatography with fluorescence detection was proposed in this paper. A simple apparatus consisting of a test tube and a cut-glass dropper was designed and applied to collect the floating extraction drop in liquid-liquid microextraction when low-density organic solvent was used as the extraction solvent. Solidification and melting steps that were tedious but necessary once the low-density organic solvent used as extraction solvent could be avoided by using this apparatus. Bisphenol A was selected as model pollutant and vortex-assisted liquid-liquid microextraction was employed to investigate the usefulness of the apparatus. High-performance liquid chromatography with fluorescence detection was selected as the analytical tool for the detection of bisphenol A. The linear dynamic range was from 0.10 to 100 μg/L for bisphenol A, with good squared regression coefficient (r(2) = 0.9990). The relative standard deviation (n = 7) was 4.7% and the limit of detection was 0.02 μg/L. The proposed method had been applied to the determination of bisphenol A in natural water samples and was shown to be economical, fast, and convenient. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Screening of synthetic PDE-5 inhibitors and their analogues as adulterants: analytical techniques and challenges.

PubMed

Patel, Dhavalkumar Narendrabhai; Li, Lin; Kee, Chee-Leong; Ge, Xiaowei; Low, Min-Yong; Koh, Hwee-Ling

2014-01-01

The popularity of phosphodiesterase type 5 (PDE-5) enzyme inhibitors for the treatment of erectile dysfunction has led to the increase in prevalence of illicit sexual performance enhancement products. PDE-5 inhibitors, namely sildenafil, tadalafil and vardenafil, and their unapproved designer analogues are being increasingly used as adulterants in the herbal products and health supplements marketed for sexual performance enhancement. To date, more than 50 unapproved analogues of prescription PDE-5 inhibitors were found as adulterants in the literature. To avoid detection of such adulteration by standard screening protocols, the perpetrators of such illegal products are investing time and resources to synthesize exotic analogues and devise novel means for adulteration. A comprehensive review of conventional and advance analytical techniques to detect and characterize the adulterants is presented. The rapid identification and structural elucidation of unknown analogues as adulterants is greatly enhanced by the wide myriad of analytical techniques employed, including high performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), liquid chromatography mass-spectrometry (LC-MS), nuclear magnetic resonance (NMR) spectroscopy, vibrational spectroscopy, liquid chromatography-Fourier transform ion cyclotron resonance-mass spectrometry (LC-FT-ICR-MS), liquid chromatograph-hybrid triple quadrupole linear ion trap mass spectrometer with information dependent acquisition, ultra high performance liquid chromatography-time of flight-mass spectrometry (UHPLC-TOF-MS), ion mobility spectroscopy (IMS) and immunoassay methods. The many challenges in detecting and characterizing such adulterants, and the need for concerted effort to curb adulteration in order to safe guard public safety and interest are discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

Liquid Chromatography at Critical Conditions: Balancing size exclusion and adsorption in nanopores

NASA Astrophysics Data System (ADS)

Abdulahad, Asem; Amos, Jeffrey; Ryu, Chang

2009-03-01

Liquid chromatography at critical condition (LCCC) is a measure to identify thermodynamic conditions, in which polymers elute independently of molar mass during high performance liquid chromatography. Under these critical conditions the entropic exclusions that dominate size exclusion chromatography (SEC) and the enthalpic adsorption that governs adsorption-based interaction chromatography (IC) are said to negate one another resulting in simultaneous elution of the polymer of different molecular weights. Using multiple C18-bonded silica columns with different average nanopore sizes (from 5 nm to 30 nm), we will study the LCCC conditions of PS in methylene chloride/acetonitrile solvent mixture at different temperature. In addition, we will show that the separation of polystyrene can be fine tuned using a refined temperature gradient interaction chromatography (TGIC) that employs multiple columns of varying pore size in sequence.

Monodisperse microbeads of hypercrosslinked polystyrene for liquid and supercritical fluid chromatography

NASA Astrophysics Data System (ADS)

Tsyurupa, M. P.; Blinnikova, Z. K.; Il'in, M. M.; Davankov, V. A.; Parenago, O. O.; Pokrovskii, O. I.; Usovich, O. I.

2015-11-01

Monodisperse styrene-divinylbenzene (1 wt %) copolymer microbeads are obtained via the elaborate method of high-productivity precipitation polymerization. The crosslinking of this copolymer with chloromethyl methyl ether in the presence of Friedel-Crafts catalyst yields porous hypercrosslinked polymers with degrees of crosslinking that range from 200 to 500%. Microbead sorbents are shown to be suited for selective stationary phases for high-performance liquid chromatography and supercritical fluid chromatography.

Enantiomeric high-performance liquid chromatography resolution and absolute configuration of 6β-benzoyloxy-3α-tropanol.

PubMed

Muñoz, Marcelo A; González, Natalia; Joseph-Nathan, Pedro

2016-07-01

The absolute configuration of the naturally occurring isomers of 6β-benzoyloxy-3α-tropanol (1) has been established by the combined use of chiral high-performance liquid chromatography with electronic circular dichroism detection and optical rotation detection. For this purpose (±)-1, prepared in two steps from racemic 6-hydroxytropinone (4), was subjected to chiral high-performance liquid chromatography with electronic circular dichroism and optical rotation detection allowing the online measurement of both chiroptical properties for each enantiomer, which in turn were compared with the corresponding values obtained from density functional theory calculations. In an independent approach, preparative high-performance liquid chromatography separation using an automatic fraction collector, yielded an enantiopure sample of OR (+)-1 whose vibrational circular dichroism spectrum allowed its absolute configuration assignment when the bands in the 1100-950 cm(-1) region were compared with those of the enantiomers of esters derived from 3α,6β-tropanediol. In addition, an enantiomerically enriched sample of 4, instead of OR (±)-4, was used for the same transformation sequence, whose high-performance liquid chromatography follow-up allowed their spectroscopic correlation. All evidences lead to the OR (+)-(1S,3R,5S,6R) and OR (-)-(1R,3S,5R,6S) absolute configurations, from where it follows that samples of 1 isolated from Knightia strobilina and Erythroxylum zambesiacum have the OR (+)-(1S,3R,5S,6R) absolute configuration, while the sample obtained from E. rotundifolium has the OR (-)-(1R,3S,5R,6S) absolute configuration. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Analysis of major antioxidants from extracts of Myrmecodia pendans by UV/visible spectrophotometer, liquid chromatography/tandem mass spectrometry, and high-performance liquid chromatography/UV techniques.

PubMed

Engida, Adam Mekonnen; Faika, Sitti; Nguyen-Thi, Bich Thuyen; Ju, Yi-Hsu

2015-06-01

In the present work, heat reflux extraction with ethanol/water (80:20; v/v) as the solvent was used to extract antioxidants from Myrmecodia pendans. The crude extract (CE) was fractionated using hexane and ethyl acetate. Ethyl acetate fraction (EAF) and aqueous fraction were collected. Antioxidant activity against 1,1-diphenyl-2-picrylhydrazyl-radical radical and ferric reducing power of the CE, EAF, and aqueous fraction were evaluated. EAF showed comparable antioxidant activity against 1,1-diphenyl-2-picrylhydrazyl-radical radical and ferric reducing power to those of the CE. UV/visible, liquid chromatography/electrospray ionization/tandem mass spectrometry, and high-performance liquid chromatography were employed for identifying the major antioxidant compounds in the EAF. Three major phenolic compounds (rosmarinic acid, procyanidin B1, and polymer of procyanidin B1) were identified. The first two compounds were confirmed and quantified by high-performance liquid chromatography using authentic standards, but confirmation of the third compound was hampered by a lack of commercial standard. Concentrations of rosmarinic acid and procyanidin B1 in the EAF were found to be 20.688 ± 1.573 mg/g dry sample and 3.236 ± 0.280 mg/g dry sample, respectively. All these three compounds are reported for the first time in sarang semut. Copyright © 2014. Published by Elsevier B.V.

[Separation and identification of bovine lactoferricin by high performance liquid chromatography-matrix-assisted laser desorption/ionization time of flight/ time of flight mass spectrometry].

PubMed

An, Meichen; Liu, Ning

2010-02-01

A high performance liquid chromatography-matrix-assisted laser desorption/ionization time of flight/time of flight mass spectrometry (HPLC-MALDI-TOF/TOF MS) method was developed for the separation and identification of bovine lactoferricin (LfcinB). Bovine lactoferrin was hydrolyzed by pepsin and then separated by ion exchange chromatography and reversed-phase liquid chromatography (RP-LC). The antibacterial activities of the fractions from RP-LC separation were determined and the protein concentration of the fraction with the highest activity was measured, whose sequence was indentified by MALDI-TOF/TOF MS. The relative molecular mass of LfcinB was 3 124.89 and the protein concentration was 18.20 microg/mL. The method of producing LfcinB proposed in this study has fast speed, high accuracy and high resolution.

Rapid characterization of the chemical constituents of Cortex Fraxini by homogenate extraction followed by UHPLC coupled with Fourier transform ion cyclotron resonance mass spectrometry and GC-MS.

PubMed

Wang, Yinan; Han, Fei; Song, Aihua; Wang, Miao; Zhao, Min; Zhao, Chunjie

2016-11-01

Cortex Fraxini is an important traditional Chinese medicine. In this work, a rapid and reliable homogenate extraction method was applied for the fast extraction for Cortex Fraxini, and the method was optimized by response surface methodology. Ultra high performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry and gas chromatography with mass spectrometry were established for the separation and characterization of the constituents of Cortex Fraxini. Liquid chromatography separation was conducted on a C 18 column (150 mm × 2.1 mm, 1.8 μm), and gas chromatography separation was performed on a capillary with a 5% phenyl-methylpolysiloxane stationary phase (30 m × 0.25 mm × 0.25 mm) by injection of silylated samples. According to the results, 33 chemical compounds were characterized by liquid chromatography with mass spectrometry, and 11 chemical compounds were characterized by gas chromatography with mass spectrometry, and coumarins were the major components characterized by both gas chromatography with mass spectrometry and liquid chromatography with mass spectrometry. The proposed homogenate extraction was an efficient and rapid method, and coumarins, phenylethanoid glycosides, iridoid glycosides, phenylpropanoids, and lignans were the main constituents of Cortex Fraxini. This work laid the foundation for further study of Cortex Fraxini and will be helpful for the rapid extraction and characterization of ingredients in other traditional Chinese medicines. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

CHARACTERIZATION OF DANSYLATED CYSTEINE, GLUTATHIONE DISULFIDE, CYSTEINE AND CYSTINE BY NARROW BORE LIQUID CHROMATOGRAPHY/ELECTROSPRAY IONIZATION MASS SPECTROMETRY

EPA Science Inventory

A method using reversed phase high performance liquid chromatography/electrospray ionization-mass spectrometric (RP-LC/ESI-MS) method has been developed to confirm the identity of dansylated derivatives of cysteine and glutathione, and their respective dimers. Cysteine, GSH, CSSC...

High Performance Liquid Chromatography of Some Analgesic Compounds: An Instrumental Analysis Experiment.

ERIC Educational Resources Information Center

Haddad, Paul; And Others

1983-01-01

Background information, procedures, and results are provided for an experiment demonstrating techniques of solvent selection, gradient elution, pH control, and ion-pairing in the analysis of an analgesic mixture using reversed-phase liquid chromatography on an octadecylsilane column. Although developed using sophisticated/expensive equipment, less…

Analysis of antimycin A by reversed-phase liquid chromatography/nuclear magnetic-resonance spectrometry

USGS Publications Warehouse

Ha, Steven T.K.; Wilkins, Charles L.; Abidi, Sharon L.

1989-01-01

A mixture of closely related streptomyces fermentation products, antimycin A, Is separated, and the components are identified by using reversed-phase high-performance liquid chromatography with directly linked 400-MHz proton nuclear magnetic resonance detection. Analyses of mixtures of three amino acids, alanine, glycine, and valine, are used to determine optimal measurement conditions. Sensitivity increases of as much as a factor of 3 are achieved, at the expense of some loss in chromatographic resolution, by use of an 80-μL NMR cell, Instead of a smaller 14-μL cell. Analysis of the antimycin A mixture, using the optimal analytical high performance liquid chromatography/nuclear magnetic resonance conditions, reveals it to consist of at least 10 closely related components.

Discovery and Synthesis of GS-5734, a Phosphoramidate Prodrug of a Pyrrolo[2,1 f][triazin-4-amino] Adenine C-Nucleoside for the Treatment of Ebola and Emerging Viruses

DTIC Science & Technology

2017-01-26

high- performance liquid chromatography (HPLC) and were greater than 95% unless otherwise noted. HPLC conditions to assess purity were as follows...cell culture plates using a μFlow liquid dispenser and cultured for 4 days at 37 °C. After incubation, the cells were allowed to equilibrate to 25...t1/2) was determined assuming first-order kinetics. LC/MS/MS Instrumentation Liquid chromatography was performed using an Agilent 1200-series

Clonazepam quantification in human plasma by high-performance liquid chromatography coupled with electrospray tandem mass spectrometry in a bioequivalence study.

PubMed

Cavedal, Luiz E; Mendes, Fabiana D; Domingues, Claudia C; Patni, Anil K; Monif, Tausif; Reyar, Simrit; Pereira, Alberto Dos S; Mendes, Gustavo D; De Nucci, Gilberto

2007-01-01

A rapid, sensitive and specific method for quantifying clonazepam in human plasma using diazepam as the internal standard (IS) is described. The analyte and the IS were extracted from plasma by liquid-liquid extraction using a hexane/diethylether (20 : 80, v/v) solution. The extracts were analysed by high-performance liquid chromatography coupled with electrospray tandem mass spectrometry (HPLC-MS-MS). Chromatography was performed on a Jones Genesis C8 4 microm analytical column (100 x 2.1 mm i.d.). The method had a chromatographic run time of 3.0 min and a linear calibration curve over the range 0.5-50 ng/ml (r2 > 0.9965). The limit of quantification was 0.5 ng/ml. This HPLC/MS/MS procedure was used to assess the bioequivalence of two clonazepam 2 mg tablet formulations (clonazepam test formulation from Ranbaxy Laboratories Ltd and Rivotril from Roche Laboratórios Ltda as standard reference formulation). Copyright 2006 John Wiley & Sons, Ltd.

Determination of the Acid Dissociation Constant of a Phenolic Acid by High Performance Liquid Chromatography: An Experiment for the Upper Level Analytical Chemistry Laboratory

ERIC Educational Resources Information Center

Raboh, Ghada

2018-01-01

A high performance liquid chromatography (HPLC) experiment for the upper level analytical chemistry laboratory is described. The students consider the effect of mobile-phase composition and pH on the retention times of ionizable compounds in order to determine the acid dissociation constant, K[subscript a], of a phenolic acid. Results are analyzed…

Determination of dasatinib in the tablet dosage form by ultra high performance liquid chromatography, capillary zone electrophoresis, and sequential injection analysis.

PubMed

Gonzalez, Aroa Garcia; Taraba, Lukáš; Hraníček, Jakub; Kozlík, Petr; Coufal, Pavel

2017-01-01

Dasatinib is a novel oral prescription drug proposed for treating adult patients with chronic myeloid leukemia. Three analytical methods, namely ultra high performance liquid chromatography, capillary zone electrophoresis, and sequential injection analysis, were developed, validated, and compared for determination of the drug in the tablet dosage form. The total analysis time of optimized ultra high performance liquid chromatography and capillary zone electrophoresis methods was 2.0 and 2.2 min, respectively. Direct ultraviolet detection with detection wavelength of 322 nm was employed in both cases. The optimized sequential injection analysis method was based on spectrophotometric detection of dasatinib after a simple colorimetric reaction with folin ciocalteau reagent forming a blue-colored complex with an absorbance maximum at 745 nm. The total analysis time was 2.5 min. The ultra high performance liquid chromatography method provided the lowest detection and quantitation limits and the most precise and accurate results. All three newly developed methods were demonstrated to be specific, linear, sensitive, precise, and accurate, providing results satisfactorily meeting the requirements of the pharmaceutical industry, and can be employed for the routine determination of the active pharmaceutical ingredient in the tablet dosage form. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluating the Antibacterial Properties of Polyacetylene and Glucosinolate Compounds with Further Identification of Their Presence within Various Carrot (Daucus carota) and Broccoli (Brassica oleracea) Cultivars Using High-Performance Liquid Chromatography with a Diode Array Detector and Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry Analyses.

PubMed

Hinds, L; Kenny, O; Hossain, M B; Walsh, D; Sheehy, E; Evans, P; Gaffney, M; Rai, D K

2017-08-23

Ongoing consumer concerns over using synthetic additives in foods has strongly influenced efforts worldwide to source suitable natural alternatives. In this study, the antibacterial efficacy of polyacetylene and glucosinolate compounds was evaluated against both Gram positive and Gram negative bacterial strains. Falcarinol [minimum inhibitory concentration (MIC) = 18.8-37.6 μg/mL] demonstrated the best overall antibacterial activity, while sinigrin (MIC = 46.9-62.5 μg/mL) was the most active glucosinolate compound. High-performance liquid chromatography with a diode array detector analysis showed falcarinol [85.13-244.85 μg/g of dry weight (DW)] to be the most abundant polyacetylene within six of the eight carrot (Daucus carota) cultivars investigated. Meanwhile, sinigrin (100.2-244.3 μg/g of DW) was the most abundant glucosinolate present within the majority of broccoli (Brassica oleracea) cultivars investigated using ultra performance liquid chromatography-tandem mass spectrometry analysis. The high abundance of both falcarinol and sinigrin within these respective species suggests that they could serve as potential sources of natural antibacterial agents for use as such in food products.

Predicting drug penetration across the blood-brain barrier: comparison of micellar liquid chromatography and immobilized artificial membrane liquid chromatography.

PubMed

De Vrieze, Mike; Lynen, Frédéric; Chen, Kai; Szucs, Roman; Sandra, Pat

2013-07-01

Several in vitro methods have been tested for their ability to predict drug penetration across the blood-brain barrier (BBB) into the central nervous system (CNS). In this article, the performance of a variety of micellar liquid chromatographic (MLC) methods and immobilized artificial membrane (IAM) liquid chromatographic approaches were compared for a set of 45 solutes. MLC measurements were performed on a C18 column with sodium dodecyl sulfate (SDS), polyoxyethylene (23) lauryl ether (Brij35), or sodium deoxycholate (SDC) as surfactant in the micellar mobile phase. IAM liquid chromatography measurements were performed with Dulbecco's phosphate-buffered saline (DPBS) and methanol as organic modifier in the mobile phase. The corresponding retention and computed descriptor data for each solute were used for construction of models to predict transport across the blood-brain barrier (log BB). All data were correlated with experimental log BB values and the relative performance of the models was studied. SDS-based models proved most suitable for prediction of log BB values, followed closely by a simplified IAM method, in which it could be observed that extrapolation of retention data to 0% modifier in the mobile phase was unnecessary.

Improved selectivity for high-performance liquid chromatographic determination of clonazepam in plasma of epileptic patients.

PubMed

Le Guellec, C; Gaudet, M L; Breteau, M

1998-11-20

We report a high-performance liquid chromatography method for clonazepam determination in plasma. The use of a synthetic silica-based stationary phase markedly improved clonazepam resolution compared to standard reversed-phase columns. A liquid-liquid extraction was used, associated with reversed-phase chromatography, gradient elution and ultraviolet detection. Accuracy and precision were satisfactory at therapeutic concentrations. Selectivity was studied for benzodiazepines or other antiepileptic drugs, with particular attention to newly marketed drugs i.e., gabapentine and vigabatrin. No interfering substance was evidenced. Under the conditions described, it was possible to quantify clonazepam at nanogram level even when carbamazepine was present at therapeutic concentrations.

Rapid screening, separation, and detection of hydroxyl radical scavengers from total flavonoids of Ginkgo biloba leaves by chromatography combined with molecular devices.

PubMed

Wang, Jing; Zheng, Meizhu; Chen, Lina; Liu, Zhiqiang; Zhang, Yuchi; Liu, Chun-Ming; Liu, Shu

2016-11-01

Hydroxyl radicals are the most reactive free radical of human body, a strong contributor to tissue damage. In this study, liquid chromatography coupled to electrospray ionization mass spectrometry was applied to screen and identify hydroxyl radical scavengers from the total flavonoids of Ginkgo biloba leaves, and high-performance counter current chromatography was used to separate and isolate the active compounds. Furthermore, molecular devices were used to determine hydroxyl radical scavenging activities of the obtained hydroxyl radical scavengers and other flavonoids from G. biloba leaves. As a result, six compounds were screened as hydroxyl radical scavengers, but only three flavonoids, namely, rutin, cosmos glycosides and apigenin-7-O-Glu-4'-O-Rha, were isolated successfully from total flavonoids by high-performance counter current chromatography. The purities of the three obtained compounds were over 90%, respectively, as determined by liquid chromatography. Molecular devices with 96-well microplates evaluation indicated that the 50% scavenging concentration values of screened compounds were lower than that of other flavonoids, they performed greater hydroxyl radical scavenging activity, and the evaluation effects were consistent with the liquid chromatography with mass spectrometry screening results. Therefore, chromatography combined with molecular devices is a feasible and an efficient method for systematic screening, identification, isolation, and evaluation of bioactive components in mixture of botanical medicines. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization of Extracellular Vesicles by Size-Exclusion High-Performance Liquid Chromatography (HPLC).

PubMed

Huang, Tao; He, Jiang

2017-01-01

Extracellular vesicles (EVs) have recently attracted substantial attention due to the potential diagnostic and therapeutic relevance. Although a variety of techniques have been used to isolate and analyze EVs, it is still far away from satisfaction. Size-exclusion chromatography (SEC), which separates subjects by size, has been widely applied in protein purification and analysis. The purpose of this chapter is to show the applications of size-exclusion high-performance liquid chromatography (HPLC) as methods for EV characterization of impurities or contaminants of small size, and thus for quality assay for the purity of the samples of EVs.

Assessing the detectability of antioxidants in two-dimensional high-performance liquid chromatography.

PubMed

Bassanese, Danielle N; Conlan, Xavier A; Barnett, Neil W; Stevenson, Paul G

2015-05-01

This paper explores the analytical figures of merit of two-dimensional high-performance liquid chromatography for the separation of antioxidant standards. The cumulative two-dimensional high-performance liquid chromatography peak area was calculated for 11 antioxidants by two different methods--the areas reported by the control software and by fitting the data with a Gaussian model; these methods were evaluated for precision and sensitivity. Both methods demonstrated excellent precision in regards to retention time in the second dimension (%RSD below 1.16%) and cumulative second dimension peak area (%RSD below 3.73% from the instrument software and 5.87% for the Gaussian method). Combining areas reported by the high-performance liquid chromatographic control software displayed superior limits of detection, in the order of 1 × 10(-6) M, almost an order of magnitude lower than the Gaussian method for some analytes. The introduction of the countergradient eliminated the strong solvent mismatch between dimensions, leading to a much improved peak shape and better detection limits for quantification. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

PubMed

Jiménez, M; Mateo, R

1997-08-22

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

Chemical fingerprint of Ganmaoling granule by double-wavelength ultra high performance liquid chromatography and ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry.

PubMed

Lou, Qiong; Ye, Xiaolan; Zhou, Yingyi; Li, Hua; Song, Fenyun

2015-06-01

A method incorporating double-wavelength ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry was developed for the investigation of the chemical fingerprint of Ganmaoling granule. The chromatographic separations were performed on an ACQUITY UPLC HSS C18 column (2.1 × 50 mm, 1.8 μm) at 30°C using gradient elution with water/formic acid (1%) and acetonitrile at a flow rate of 0.4 mL/min. A total of 11 chemical constituents of Ganmaoling granule were identified from their molecular weight, UV spectra, tandem mass spectrometry data, and retention behavior by comparing the results with those of the reference standards or literature. And 25 peaks were selected as the common peaks for fingerprint analysis to evaluate the similarities among 25 batches of Ganmaoling granule. The results of principal component analysis and orthogonal projection to latent structures discriminant analysis showed that the important chemical markers that could distinguish the different batches were revealed as 4,5-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid, and 4-O-caffeoylquinic acid. This is the first report of the ultra high performance liquid chromatography chemical fingerprint and component identification of Ganmaoling granule, which could lay a foundation for further studies of Ganmaoling granule. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Separation of enantiomers of new psychoactive substances by high-performance liquid chromatography.

PubMed

Kadkhodaei, Kian; Forcher, Lisa; Schmid, Martin G

2018-03-01

New psychoactive substances are defined as compounds with consciousness-changing effects and have been developed simultaneously with classical drugs. They arise through structural modifications of illegal substances and are mainly produced to circumvent laws. Availability is simple, since new psychoactive substances can be purchased from the Internet. Among them many chemical drug compound classes are chiral and thus the two resulting enantiomers can differ in their effects. The aim of this study is to develop a suitable chiral high-performance liquid chromatography separation method for a broad spectrum of new psychoactive substances using cellulose tris(3,5-dichlorophenylcarbamate) as a chiral selector. Experiments were performed by high-performance liquid chromatography in normal-phase mode under isocratic conditions using ultraviolet detection. Direct separation was carried out on a high-performance liquid chromatography column (Lux® i-Cellulose-5, 3.5 μm, Phenomenex®), available since 2016. Excellent separation results were obtained for cathinones. After further optimization, even 47 instead of 39 out of 52 cathinones showed baseline separation. For amphetamine derivatives, satisfactory results were not achieved. Further, new psychoactive substances from other compound classes such as benzofuranes, thiophenes, phenidines, phenidates, morpholines, and ketamines were partially resolved, depending on the polarity and degree of substitution. All analytes, which were mainly purchased from the Internet, were proven to be traded as racemates. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A simple, rapid and validated high-performance liquid chromatography method suitable for clinical measurements of human mercaptalbumin and non-mercaptalbumin.

PubMed

Yasukawa, Keiko; Shimosawa, Tatsuo; Okubo, Shigeo; Yatomi, Yutaka

2018-01-01

Background Human mercaptalbumin and human non-mercaptalbumin have been reported as markers for various pathological conditions, such as kidney and liver diseases. These markers play important roles in redox regulations throughout the body. Despite the recognition of these markers in various pathophysiologic conditions, the measurements of human mercaptalbumin and non-mercaptalbumin have not been popular because of the technical complexity and long measurement time of conventional methods. Methods Based on previous reports, we explored the optimal analytical conditions for a high-performance liquid chromatography method using an anion-exchange column packed with a hydrophilic polyvinyl alcohol gel. The method was then validated using performance tests as well as measurements of various patients' serum samples. Results We successfully established a reliable high-performance liquid chromatography method with an analytical time of only 12 min per test. The repeatability (within-day variability) and reproducibility (day-to-day variability) were 0.30% and 0.27% (CV), respectively. A very good correlation was obtained with the results of the conventional method. Conclusions A practical method for the clinical measurement of human mercaptalbumin and non-mercaptalbumin was established. This high-performance liquid chromatography method is expected to be a powerful tool enabling the expansion of clinical usefulness and ensuring the elucidation of the roles of albumin in redox reactions throughout the human body.

Quality evaluation of Semen Cassiae (Cassia obtusifolia L.) by using ultra-high performance liquid chromatography coupled with mass spectrometry.

PubMed

Zhang, Wei-Dong; Wang, Ying; Wang, Qing; Yang, Wan-Jun; Gu, Yi; Wang, Rong; Song, Xiao-Mei; Wang, Xiao-Juan

2012-08-01

A sensitive and reliable ultra-high performance liquid chromatography-electrospray ionization-tandem mass spectrometry has been developed and partially validated to evaluate the quality of Semen Cassiae (Cassia obtusifolia L.) through simultaneous determination of 11 anthraquinones and two naphtha-γ-pyrone compounds. The analysis was achieved on a Poroshell 120 EC-C(18) column (100 mm × 2.1 mm, 2.7 μm; Agilent, Palo Alto, CA, USA) with gradient elution using a mobile phase that consisted of acetonitrile-water (30 mM ammonium acetate) at a flow rate of 0.4 mL/min. For quantitative analysis, all calibration curves showed perfect linear regression (r(2) > 0.99) within the testing range. This method was also validated with respect to precision and accuracy, and was successfully applied to quantify the 13 components in nine batches of Semen Cassiae samples from different areas. The performance of developed method was compared with that of conventional high-performance liquid chromatography method. The significant advantages of the former include high-speed chromatographic separation, four times faster than high-performance liquid chromatography with conventional columns, and great enhancement in sensitivity. This developed method provided a new basis for overall assessment on quality of Semen Cassiae. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Detection of radiation-induced hydrocarbons in baked sponged cake prepared with irradiated liquid egg

NASA Astrophysics Data System (ADS)

Schulzki, G.; Spiegelberg, A.; Bögl, K. W.; Schreiber, G. A.

1995-02-01

For identification of irradiated food, radiation-induced volatile hydrocarbons (HC) are determined by gas chromatography in the non-polar fraction of fat. However, in complex food matrices the detection is often disturbed by fat-associated compounds. On-line coupling of high performance liquid chromatography (LC) and gas chromatography (GC) is very efficient to remove such compounds from the HC fraction. The high sensitivity of this fast and efficient technique is demonstrated by the example of detection of radiation-induced HC in fat isolated from baked sponge cake which had been prepared with irradiated liquid egg.

Development of an on-line mixed-mode gel liquid chromatography×reversed phase liquid chromatography method for separation of water extract from Flos Carthami.

PubMed

Wang, Yu-Qing; Tang, Xu; Li, Jia-Fu; Wu, Yun-Long; Sun, Yu-Ying; Fang, Mei-Juan; Wu, Zhen; Wang, Xiu-Min; Qiu, Ying-Kun

2017-10-13

A novel on-line comprehensive two-dimensional liquid chromatography (2D-LC) method by coupling mixed-mode gel liquid chromatography (MMG-LC) with reversed phase liquid chromatography (RPLC) was developed. A mixture of 17 reference compounds was used to study the separation mechanism. A crude water extract of Flos Carthami was applied to evaluate the performance of the novel 2D-LC system. In the first dimension, the extract was eluted with a gradient of water/methanol over a cross-linked dextran gel Sephadex LH-20 column. Meanwhile, the advantages of size exclusion, reversed phase partition and adsorption separation mechanism were exploited before further on-line reversed phase purification on the second dimension. This novel on-line mixed-mode Sephadex LH-20×RPLC method provided higher peak resolution, sample processing ability (2.5mg) and better orthogonality (72.9%) versus RPLC×RPLC and hydrophilic interaction liquid chromatography (HILIC)×RPLC. To the best of our knowledge, this is the first report of a mixed-mode Sephadex LH-20×RPLC separation method with successful applications in on-line mode, which might be beneficial for harvesting targets from complicated medicinal plants. Copyright © 2017 Elsevier B.V. All rights reserved.

Progressing the analysis of Improvised Explosive Devices: Comparative study for trace detection of explosive residues in handprints by Raman spectroscopy and liquid chromatography.

PubMed

Zapata, Félix; de la Ossa, Mª Ángeles Fernández; Gilchrist, Elizabeth; Barron, Leon; García-Ruiz, Carmen

2016-12-01

Concerning the dreadful global threat of terrorist attacks, the detection of explosive residues in biological traces and marks is a current need in both forensics and homeland security. This study examines the potential of Raman microscopy in comparison to liquid chromatography (ion chromatography (IC) and reversed-phase high performance liquid chromatography (RP-HPLC)) to detect, identify and quantify residues in human handmarks of explosives and energetic salts commonly used to manufacture Improvised Explosive Devices (IEDs) including dynamite, ammonium nitrate, single- and double-smokeless gunpowders and black powder. Dynamite, ammonium nitrate and black powder were detected through the identification of the energetic salts by Raman spectroscopy, their respective anions by IC, and organic components by RP-HPLC. Smokeless gunpowders were not detected, either by Raman spectroscopy or the two liquid chromatography techniques. Several aspects of handprint collection, sample treatment and a critical comparison of the identification of compounds by both techniques are discussed. Raman microscopy and liquid chromatography were shown to be complementary to one another offering more comprehensive information for trace explosives analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

Ultra-Trace Analysis of Nine Macrolides, including Tulathromycin A (Draxxin), in Edible Animal Tissues with Mini-Column Liquid Chromatography Tandem Mass Spectrometry

USDA-ARS?s Scientific Manuscript database

Analysis of 9 macrolides is presented, including tulathromycin A (Draxxin), in beef, poultry and pork muscle with a simple multi-residue extraction and analysis method using high performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry. The extraction method inv...

MEASUREMENT OF HIGH-MOLECULAR-WEIGHT POLYCYCLIC AROMATIC HYDROCARBONS IN SOILS BY PARTICLE BEAM HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY-MASS SPECTROMETRY

EPA Science Inventory

Polycyclic aromatic hydrocarbons (PAHs) comprise a class of potentially hazardous compounds of concern to the U.S.EPA. The application of particle-beam (PB) liquid chromatography-mass spectrometry (LC-MS) to the measurement of high-molecular-weight PAHs was investigated. Instrume...

Matrix effects break the LC behavior rule for analytes in LC-MS/MS analysis of biological samples

USDA-ARS?s Scientific Manuscript database

High-performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) are generally accepted as the preferred techniques for detecting and quantitating analytes of interest in biological matrices on the basis of the rule that one chemical compound yields one LC-...

Major and Modified Nucleosides, RNA, and DNA

NASA Astrophysics Data System (ADS)

Gehrke, Charles W.; Kuo, Kenneth C.

Most analytical chemists are well aware of the rapid rate of development of high-performance liquid chromatography (HPLC) over the past 5 years. A number of articles have been published in Analytical Chemistry on different topics in HPLC and many papers appear in the chromatographic journals. Some books also have been published covering this subject. HPLC has proved to be a very effective, broadly applicable chromatographic method for the separation and analysis of complex molecules in fields as diverse as biochemistry and environmental, pharmaceutical, medical, and polymer chemistry. HPLC is now having a major impact on the clinical and research aspects of medical biochemistry. Although the contributions of HPLC to other disciplines generally complements gas-liquid chromatography, this method is destined to play a much greater role in medical and biochemical research. This is because many of the biomolecules, owing to their molecular complexity and size, are thermally unstable or nonvolatile, preventing or complicating an analysis by GC. A major factor contributing to the powerful advances in biomedical liquid chromatography is the development of reversed-phase high-performance liquid chromatography (RP-HPLC) using n-alkyl and phenyl chemically bonded substrates.

Overview of online two-dimensional liquid chromatography based on cell membrane chromatography for screening target components from traditional Chinese medicines.

PubMed

Muhammad, Saqib; Han, Shengli; Xie, Xiaoyu; Wang, Sicen; Aziz, Muhammad Majid

2017-01-01

Cell membrane chromatography is a simple, specific, and time-saving technique for studying drug-receptor interactions, screening of active components from complex mixtures, and quality control of traditional Chinese medicines. However, the short column life, low sensitivity, low column efficiency (so cannot resolve satisfactorily mixture of compounds), low peak capacity, and inefficient in structure identification were bottleneck in its application. Combinations of cell membrane chromatography with multidimensional chromatography such as two-dimensional liquid chromatography and high sensitivity detectors like mass have significantly reduced many of the above-mentioned shortcomings. This paper provides an overview of the current advances in online two-dimensional-based cell membrane chromatography for screening target components from traditional Chinese medicines with particular emphasis on the instrumentation, preparation of cell membrane stationary phase, advantages, and disadvantages compared to alternative approaches. The last section of the review summarizes the applications of the online two-dimensional high-performance liquid chromatography based cell membrane chromatography reported since its emergence to date (2010-June 2016). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Separation of amino acids and antibiotics by narrow-bore and normal-bore high-performance liquid chromatography with pre-column derivatization.

PubMed

Fiedler, H P; Plaga, A

1987-01-16

The selectivity, efficiency and lifetime of normal- and narrow-bore columns for high-performance liquid chromatography were investigated for the separation and quantification of amino acids and the amino acid-like antibiotics phosphinothricin and phosphinothricylalanylalanine in biological samples. These compounds were determined by an automated pre-column derivatization with o-phthalaldehyde-2-mercaptoethanol reagent and UV detection at 338 nm.

Determination of the Antibiotic Oxytetracycline in Commercial Milk by Solid-Phase Extraction: A High-Performance Liquid Chromatography (HPLC) Experiment for Quantitative Instrumental Analysis

ERIC Educational Resources Information Center

Mei-Ratliff, Yuan

2012-01-01

Trace levels of oxytetracylcine spiked into commercial milk samples are extracted, cleaned up, and preconcentrated using a C[subscript 18] solid-phase extraction column. The extract is then analyzed by a high-performance liquid chromatography (HPLC) instrument equipped with a UV detector and a C[subscript 18] column (150 mm x 4.6 mm x 3.5 [mu]m).…

High-Performance Liquid Chromatography (HPLC) Measurements of Phytoplankton Pigment Distributions of Ocean Waters

DTIC Science & Technology

1988-11-01

coccolithophorids 19. ABSTRACT (CanMyw on rviosfe Inhcesway aM den*t byblock nmber) Until the application of high-performance liquid chromatography (HPLC) to... phycocyanin , has a maximum 0 01 absorption peak. The spectra for the 008 chlorophyll degradation products (chlo- 0.06 rophyllides, phaeophorbides and...phaeo- phytins) which are not shown in Figure z I have similar absorption maxima as their associated chlorophylls, 002 , Until the application of high

Detection of argan oil adulteration with vegetable oils by high-performance liquid chromatography-evaporative light scattering detection.

PubMed

Salghi, Rachid; Armbruster, Wolfgang; Schwack, Wolfgang

2014-06-15

Triacylglycerol profiles were selected as indicator of adulteration of argan oils to carry out a rapid screening of samples for the evaluation of authenticity. Triacylglycerols were separated by high-performance liquid chromatography-evaporative light scattering detection. Different peak area ratios were defined to sensitively detect adulteration of argan oil with vegetable oils such as sunflower, soy bean, and olive oil up to the level of 5%. Based on four reference argan oils, mean limits of detection and quantitation were calculated to approximately 0.4% and 1.3%, respectively. Additionally, 19 more argan oil reference samples were analysed by high-performance liquid chromatography-refractive index detection, resulting in highly comparative results. The overall strategy demonstrated a good applicability in practise, and hence a high potential to be transferred to routine laboratories. Copyright © 2013 Elsevier Ltd. All rights reserved.

Simultaneous determination of the HIV nucleoside analogue reverse transcriptase inhibitors lamivudine, didanosine, stavudine, zidovudine and abacavir in human plasma by reversed phase high performance liquid chromatography.

PubMed

Verweij-van Wissen, C P W G M; Aarnoutse, R E; Burger, D M

2005-02-25

A reversed phase high performance liquid chromatography method was developed for the simultaneous quantitative determination of the nucleoside reverse transcriptase inhibitors (NRTIs) lamivudine, didanosine, stavudine, zidovudine and abacavir in plasma. The method involved solid-phase extraction with Oasis MAX cartridges from plasma, followed by high performance liquid chromatography with a SymmetryShield RP 18 column and ultraviolet detection set at a wavelength of 260 nm. The assay was validated over the concentration range of 0.015-5 mg/l for all five NRTIs. The average accuracies for the assay were 92-102%, inter- and intra-day coefficients of variation (CV) were <2.5% and extraction recoveries were higher than 97%. This method proved to be simple, accurate and precise, and is currently in use in our laboratory for the quantitative analysis of NRTIs in plasma.

Separation of Poly(styrene-block-t-butyl methacrylate) Copolymers by Various Liquid Chromatography Techniques

PubMed Central

Šmigovec Ljubič, Tina; Pahovnik, David; Žigon, Majda; Žagar, Ema

2012-01-01

The separation of a mixture of three poly(styrene-block-t-butyl methacrylate) copolymers (PS-b-PtBMA), consisting of polystyrene (PS) blocks of similar length and t-butyl methacrylate (PtBMA) blocks of different lengths, was performed using various chromatographic techniques, that is, a gradient liquid chromatography on reversed-phase (C18 and C8) and normal-phase columns, a liquid chromatography under critical conditions for polystyrene as well as a fully automated two-dimensional liquid chromatography that separates block copolymers by chemical composition in the first dimension and by molar mass in the second dimension. The results show that a partial separation of the mixture of PS-b-PtBMA copolymers can be achieved only by gradient liquid chromatography on reversed-phase columns. The coelution of the two block copolymers is ascribed to a much shorter PtBMA block length, compared to the PS block, as well as a small difference in the length of the PtBMA block in two of these copolymers, which was confirmed by SEC-MALS and NMR spectroscopy. PMID:22489207

Comprehensive two-dimensional normal-phase liquid chromatography × reversed-phase liquid chromatography for analysis of toad skin.

PubMed

Li, Jia-Fu; Yan, Xia; Wu, Yun-Long; Fang, Mei-Juan; Wu, Zhen; Qiu, Ying-Kun

2017-04-15

An analytical two-dimensional normal-phase liquid chromatography × reversed-phase liquid chromatography (2D NPLC × RPLC) system was constructed with a newly developed thermal evaporation assisted adsorption (TEAA) interface. This novel TEAA interface with heating temperature above solvent boiling point allowed fast removal of organic NPLC solvent and successfully solved the solvent incompatibility problem between NPLC and RPLC. The system achieved rapid on-line solvent exchange between the two dimensions within a short modulation time of 190 s and was applied in the analysis of an extract from the skin of Bufo bufo gargarizans. This is the first time to realize the on-line comprehensive analysis of a moderate polar natural product by coupling NPLC with reversed phase ultra-high performance liquid chromatography (UHPLC). To be highlighted, with the TEAA interface, the 2D NPLC × RPLC system provided excellent resolution and orthogonality (75.2%), when compared with that of 2D RPLC × RPLC. Copyright © 2017 Elsevier B.V. All rights reserved.

A simple liquid extraction protocol for overcoming the ion suppression of triacylglycerols by phospholipids in liquid chromatography mass spectrometry studies.

PubMed

Araujo, Pedro; Tilahun, Ephrem; Breivik, Joar Fjørtoft; Abdulkader, Bashir M; Frøyland, Livar; Zeng, Yingxu

2016-02-01

It is well-known that triacylglycerol (TAG) ions are suppressed by phospholipid (PL) ions in regiospecific analysis of TAG by mass spectrometry (MS). Hence, it is essential to remove the PL during sample preparation prior to MS analysis. The present article proposes a cost-effective liquid-liquid extraction (LLE) method to remove PL from TAG in different kinds of biological samples by using methanol, hexane and water. High performance thin layer chromatography confirmed the lack of PL in krill oil and salmon liver samples, submitted to the proposed LLE protocol, and liquid chromatography tandem MS confirmed that the identified TAG ions were highly enhanced after implementing the LLE procedure. Copyright © 2015 Elsevier B.V. All rights reserved.

Simultaneous determination of caffeine, paracetamol, and ibuprofen in pharmaceutical formulations by high-performance liquid chromatography with UV detection and by capillary electrophoresis with conductivity detection.

PubMed

Cunha, Rafael R; Chaves, Sandro C; Ribeiro, Michelle M A C; Torres, Lívia M F C; Muñoz, Rodrigo A A; Dos Santos, Wallans T P; Richter, Eduardo M

2015-05-01

Paracetamol, caffeine and ibuprofen are found in over-the-counter pharmaceutical formulations. In this work, we propose two new methods for simultaneous determination of paracetamol, caffeine and ibuprofen in pharmaceutical formulations. One method is based on high-performance liquid chromatography with diode-array detection and the other on capillary electrophoresis with capacitively coupled contactless conductivity detection. The separation by high-performance liquid chromatography with diode-array detection was achieved on a C18 column (250×4.6 mm(2), 5 μm) with a gradient mobile phase comprising 20-100% acetonitrile in 40 mmol L(-1) phosphate buffer pH 7.0. The separation by capillary electrophoresis with capacitively coupled contactless conductivity detection was achieved on a fused-silica capillary (40 cm length, 50 μm i.d.) using 10 mmol L(-1) 3,4-dimethoxycinnamate and 10 mmol L(-1) β-alanine with pH adjustment to 10.4 with lithium hydroxide as background electrolyte. The determination of all three pharmaceuticals was carried out in 9.6 min by liquid chromatography and in 2.2 min by capillary electrophoresis. Detection limits for caffeine, paracetamol and ibuprofen were 4.4, 0.7, and 3.4 μmol L(-1) by liquid chromatography and 39, 32, and 49 μmol L(-1) by capillary electrophoresis, respectively. Recovery values for spiked samples were between 92-107% for both proposed methods. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

New on-line separation workflow of microbial metabolites via hyphenation of analytical and preparative comprehensive two-dimensional liquid chromatography.

PubMed

Yan, Xia; Wang, Li-Juan; Wu, Zhen; Wu, Yun-Long; Liu, Xiu-Xiu; Chang, Fang-Rong; Fang, Mei-Juan; Qiu, Ying-Kun

2016-10-15

Microbial metabolites represent an important source of bioactive natural products, but always exhibit diverse of chemical structures or complicated chemical composition with low active ingredients content. Traditional separation methods rely mainly on off-line combination of open-column chromatography and preparative high performance liquid chromatography (HPLC). However, the multi-step and prolonged separation procedure might lead to exposure to oxygen and structural transformation of metabolites. In the present work, a new two-dimensional separation workflow for fast isolation and analysis of microbial metabolites from Chaetomium globosum SNSHI-5, a cytotoxic fungus derived from extreme environment. The advantage of this analytical comprehensive two-dimensional liquid chromatography (2D-LC) lies on its ability to analyze the composition of the metabolites, and to optimize the separation conditions for the preparative 2D-LC. Furthermore, gram scale preparative 2D-LC separation of the crude fungus extract could be performed on a medium-pressure liquid chromatograph×preparative high-performance liquid chromatography system, under the optimized condition. Interestingly, 12 cytochalasan derivatives, including two new compounds named cytoglobosin Ab (3) and isochaetoglobosin Db (8), were successfully obtained with high purity in a short period of time. The structures of the isolated metabolites were comprehensively characterized by HR ESI-MS and NMR. To be highlighted, this is the first report on the combination of analytical and preparative 2D-LC for the separation of microbial metabolites. The new workflow exhibited apparent advantages in separation efficiency and sample treatment capacity compared with conventional methods. Copyright © 2016 Elsevier B.V. All rights reserved.

Rapid quantitative analysis of individual anthocyanin content based on high-performance liquid chromatography with diode array detection with the pH differential method.

PubMed

Wang, Huayin

2014-09-01

A new quantitative technique for the simultaneous quantification of the individual anthocyanins based on the pH differential method and high-performance liquid chromatography with diode array detection is proposed in this paper. The six individual anthocyanins (cyanidin 3-glucoside, cyanidin 3-rutinoside, petunidin 3-glucoside, petunidin 3-rutinoside, and malvidin 3-rutinoside) from mulberry (Morus rubra) and Liriope platyphylla were used for demonstration and validation. The elution of anthocyanins was performed using a C18 column with stepwise gradient elution and individual anthocyanins were identified by high-performance liquid chromatography with tandem mass spectrometry. Based on the pH differential method, the high-performance liquid chromatography peak areas of maximum and reference absorption wavelengths of anthocyanin extracts were conducted to quantify individual anthocyanins. The calibration curves for these anthocyanins were linear within the range of 10-5500 mg/L. The correlation coefficients (r(2)) all exceeded 0.9972, and the limits of detection were in the range of 1-4 mg/L at a signal-to-noise ratio ≥5 for these anthocyanins. The proposed quantitative analysis was reproducible with good accuracy of all individual anthocyanins ranging from 96.3 to 104.2% and relative recoveries were in the range 98.4-103.2%. The proposed technique is performed without anthocyanin standards and is a simple, rapid, accurate, and economical method to determine individual anthocyanin contents. © 2014 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.

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.

Liquid Crystals in Chromatography

NASA Astrophysics Data System (ADS)

Witkiewicz, Zygfryd

The following sections are included: * INTRODUCTION * LIQUID CRYSTALS SUITABLE FOR GAS CHROMATOGRAPHY * Monomeric Liquid Crystal Stationary Phases * Polymeric Liquid Crystal Stationary Phases * Polymeric Liquid Crystal Stationary Phases * Conventional Analytical Columns * Capillary Columns * FACTORS AFFECTING THE CHROMATOGRAPHIC SEPARATIONS ON LIQUID CRYSTAL STATIONARY PHASES * Kind of Mesophase of the Liquid Crystal * Molecular Structure of the Liquid Crystals and of the Chromatographed Substances * Substrate on which the Liquid Crystal is Deposited * ANALYTICAL APPLICATIONS OF LIQUID CRYSTAL STATIONARY PHASES IN GAS CHROMATOGRAPHY * Separation of Isomers of Benzene and Naphthalene Derivatives * Separation of Alkane and Alkene Isomers * Separation of Mixtures of Benzene and Aliphatic Hydrocarbon Derivatives Containing Heteroatoms * Separation of Polynuclear Hydrocarbons * INVESTIGATION OF THE PROPERTIES OF LIQUID CRYSTALS BY GAS CHROMATOGRAPHY * APPLICATION OF LIQUID CRYSTALS IN LIQUID CHROMATOGRAPHY * Column Chromatography * Thin-Layer Chromatography * APPLICATION OF LIQUID CRYSTAL STATIONARY PHASES IN SUPERCRITICAL FLUID CHROMATOGRAPHY * FINAL REMARKS * References

[Rapid identification of micro-constituents in monoammonium glycyrrhizinate raw materials by high-pressure solid phase extraction-high performance liquid chromatography-mass spectrometry].

PubMed

Yang, Xue-Dong; Tang, Xu-Yan; Sang, Lin

2012-11-01

To establish a method for rapid identification of micro-constituents in monoammonium glycyrrhizinate by high-pressure solid phase extraction-high performance liquid chromatography-mass spectrometry. HPLC preparative chromatograph was adopted for determining the optimal method for high-pressure solid phase extraction under optimal conditions. 5C18-MS-II column (20.0 mm x 20.0 mm) was used as the extraction column, with 35% acetonitrile-acetic acid solution (pH 2. 20) as eluent at the speed of 16 mL x min(-1). The sample size was 0.5 mL, and the extraction cycle was 4.5 min. Then, extract liquid was analyzed by high performance liquid chromatography-mass spectrometry (HPLC-MS) after being concentrated by 100 times. Under the optimal condition of high-pressure solid phase extraction-high performance liquid chromatography-mass spectrometry, 10 components were rapidly identified from monoammonium glycyrrhizinate raw materials. Among them, the chemical structures of six micro-constituents were identified as 3-O-[beta-D-glucuronopyranosyl-beta-D-glucuronopyranosyl]-30-0-beta-D-apiopyranosylglycyrrhetic/3-O- [P-D-glucuronopyranosyl-beta-D-glucuronopyranosyl]-30-O-beta-D-arabinopyranosylglycyrrhetic, glycyrrhizic saponin F3, 22-hydroxyglycyrrhizin/18alpha-glycyrrhizic saponin G2, 3-O-[beta-D-rhamnopyranosyl]-24-hydroxyglycyrrhizin, glycyrrhizic saponin J2, and glycyrrhizic saponin B2 by MS(n) spectra analysis and reference to literatures. Four main chemical components were identified as glycyrrhizic saponin G2, 18beta-glycyrrhizic acid, uralglycyrrhizic saponin B and 18alpha-glycyrrhizic acid by liquid chromatography, MS(n) and ultraviolet spectra information and comparison with reference substances. The method can be used to identify chemical constituents in monoammonium glycyrrhizinate quickly and effectively, without any reference substance, which provides basis for quality control and safe application of monoammonium glycyrrhizinate-related products.

Quantitative Analysis of Tetramethylenedisulfotetramine ("Tetramine") Spiked into Beverages by Liquid Chromatography Tandem Mass Spectrometry with Validation by Gas Chromatography Mass Spectrometry

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

Owens, J; Hok, S; Alcaraz, A

Tetramethylenedisulfotetramine, commonly known as tetramine, is a highly neurotoxic rodenticide (human oral LD{sub 50} = 0.1 mg/kg) used in hundreds of deliberate food poisoning events in China. Here we describe a method for quantitation of tetramine spiked into beverages, including milk, juice, tea, cola, and water and cleaned up by C8 solid phase extraction and liquid-liquid extraction. Quantitation by high performance liquid chromatography tandem mass spectrometry (LC/MS/MS) was based upon fragmentation of m/z 347 to m/z 268. The method was validated by gas chromatography mass spectrometry (GC/MS) operated in SIM mode for ions m/z 212, 240, and 360. The limitmore » of quantitation was 0.10 {micro}g/mL by LC/MS/MS versus 0.15 {micro}g/mL for GC/MS. Fortifications of the beverages at 2.5 {micro}g/mL and 0.25 {micro}g/mL were recovered ranging from 73-128% by liquid-liquid extraction for GC/MS analysis, 13-96% by SPE and 10-101% by liquid-liquid extraction for LC/MS/MS analysis.« less

Liquid chromatography-electrospray ionization mass spectrometry analysis of limonoids and flavanois in seeds of grapefruits, other citrus species, and dietary supplements

USDA-ARS?s Scientific Manuscript database

A selective ultra-high performance liquid chromatography-didode array detector-quadrapole time of flight-mass spectrometry (UHPLC-DAD-QToF-MS) method has been developed to screen grapefruit seeds, and other citrus seed samples for limonoid aglycones, limonoid acids, limonoid glucosides and flavonoid...

Quantitative separation of tetralin hydroperoxide from its decomposition products by high performance liquid chromatography

NASA Technical Reports Server (NTRS)

Worstell, J. H.; Daniel, S. R.

1981-01-01

A method for the separation and analysis of tetralin hydroperoxide and its decomposition products by high pressure liquid chromatography has been developed. Elution with a single, mixed solvent from a micron-Porasil column was employed. Constant response factors (internal standard method) over large concentration ranges and reproducible retention parameters are reported.

The Trace Analysis of DEET in Water using an On-line Preconcentration Column and Liquid Chromatography with UV Photodiode Array Detection

EPA Science Inventory

A method for the detection of trace levels of N,N-diethyl-m-toluamide (DEET) in water is discussed. The method utilizes an on-line preconcentration column in series with high performance liquid chromatography (HPLC) and UV photodiode array detection. DEET, a common insect repel...

On-line comprehensive two-dimensional normal-phase liquid chromatography×reversed-phase liquid chromatography for preparative isolation of toad venom.

PubMed

Li, Jia-Fu; Fang, Hua; Yan, Xia; Chang, Fang-Rong; Wu, Zhen; Wu, Yun-Long; Qiu, Ying-Kun

2016-07-22

An on-line comprehensive preparative two-dimensional normal-phase liquid chromatography×reversed-phase liquid chromatography (2D NPLC×RPLC) system was constructed with a newly developed vacuum evaporation assisted adsorption (VEAA) interface, allowing fast removal of NPLC solvent in the vacuum condition and successfully solving the solvent incompatibility problem between NPLC and RPLC. The system achieved on-line solvent exchange within the two dimensions and its performance was illustrated by gram-scale isolation of crude extract from the venom of Bufo bufo gargarizans. Within separation time of ∼20h, 19 compounds were obtained with high purity in a single run. With the VEAA interface, the 2D system exhibited apparent advantages in separation efficiency and automation compared with conventional methods, indicating its promising application in the routine separation process for complicated natural products. Copyright © 2016 Elsevier B.V. All rights reserved.

Cellulose tris-(3,5-dimethylphenylcarbamate)-based chiral stationary phase for the enantioseparation of drugs in supercritical fluid chromatography: comparison with HPLC.

PubMed

Kalíková, Květa; Martínková, Monika; Schmid, Martin G; Tesařová, Eva

2018-03-01

A cellulose tris-(3,5-dimethylphenylcarbamate)-based chiral stationary phase was studied as a tool for the enantioselective separation of 21 selected analytes with different pharmaceutical and physicochemical properties. The enantioseparations were performed using supercritical fluid chromatography. The effect of the mobile phase composition was studied. Four different additives (diethylamine, triethylamine, isopropylamine, and trifluoroacetic acid) and isopropylamine combined with trifluoroacetic acid were tested and their influence on enantioseparation was compared. The influence of two different mobile phase co-solvents (methanol and propan-2-ol) combined with all the additives was also evaluated. The best mobile phase compositions for the separation of the majority of enantiomers were CO 2 /methanol/isopropylamine 80:20:0.1 v/v/v or CO 2 /propan-2-ol/isopropylamine/trifluoroacetic acid 80:20:0.05:0.05 v/v/v/v. The best results were obtained from the group of basic β-blockers. A high-performance liquid chromatography separation system composed of the same stationary phase and mobile phase of similar properties prepared as a mixture of hexane/propan-2-ol/additive 80:20:0.1 v/v/v was considered for comparison. Supercritical fluid chromatography was found to yield better results, i.e. better enantioresolution for shorter analysis times than high-performance liquid chromatography. However, examples of enantiomers better resolved under the optimized conditions in high-performance liquid chromatography were also found. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High Performance Liquid Chromatography

NASA Astrophysics Data System (ADS)

Talcott, Stephen

High performance liquid chromatography (HPLC) has many applications in food chemistry. Food components that have been analyzed with HPLC include organic acids, vitamins, amino acids, sugars, nitrosamines, certain pesticides, metabolites, fatty acids, aflatoxins, pigments, and certain food additives. Unlike gas chromatography, it is not necessary for the compound being analyzed to be volatile. It is necessary, however, for the compounds to have some solubility in the mobile phase. It is important that the solubilized samples for injection be free from all particulate matter, so centrifugation and filtration are common procedures. Also, solid-phase extraction is used commonly in sample preparation to remove interfering compounds from the sample matrix prior to HPLC analysis.

Retention of nucleic acids in ion-pair reversed-phase high-performance liquid chromatography depends not only on base composition but also on base sequence.

PubMed

Qiao, Jun-Qin; Liang, Chao; Wei, Lan-Chun; Cao, Zhao-Ming; Lian, Hong-Zhen

2016-12-01

The study on nucleic acid retention in ion-pair reversed-phase high-performance liquid chromatography mainly focuses on size-dependence, however, other factors influencing retention behaviors have not been comprehensively clarified up to date. In this present work, the retention behaviors of oligonucleotides and double-stranded DNAs were investigated on silica-based C 18 stationary phase by ion-pair reversed-phase high-performance liquid chromatography. It is found that the retention of oligonucleotides was influenced by base composition and base sequence as well as size, and oligonucleotides prone to self-dimerization have weaker retention than those not prone to self-dimerization but with the same base composition. However, homo-oligonucleotides are suitable for the size-dependent separation as a special case of oligonucleotides. For double-stranded DNAs, the retention is also influenced by base composition and base sequence, as well as size. This may be attributed to the interaction of exposed bases in major or minor grooves with the hydrophobic alky chains of stationary phase. In addition, no specific influence of guanine and cytosine content was confirmed on retention of double-stranded DNAs. Notably, the space effect resulted from the stereostructure of nucleic acids also influences the retention behavior in ion-pair reversed-phase high-performance liquid chromatography. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of monodisperse silica microspheres and modification with diazoresin for mixed-mode ultra high performance liquid chromatography separations.

PubMed

Cong, Hailin; Yu, Bing; Tian, Chao; Zhang, Shuai; Yuan, Hua

2017-11-01

Monodisperse silica particles with average diameters of 1.9-2.9 μm were synthesized by a modified Stöber method, in which tetraethyl orthosilicate was continuously supplied to the reaction mixture containing KCl electrolyte, water, ethanol, and ammonia. The obtained silica particles were modified by self-assembly with positively charged photosensitive diazoresin on the surface. After treatment with ultraviolet light, the ionic bonding between silica and diazoresin was converted into covalent bonding through a unique photochemistry reaction of diazoresin. Depending on the chemical structure of diazoresin and mobile phase composition, the diazoresin-modified silica stationary phase showed different separation mechanisms, including reversed phase and hydrophilic interactions. Therefore, a variety of baseline separation of benzene analogues and organic acids was achieved by using the diazoresin-modified silica particles as packing materials in ultra high performance liquid chromatography. According to the π-π interactional difference between carbon rings of fullerenes and benzene rings of diazoresin, C 60 and C 70 were also well separated by ultra-high performance liquid chromatography. Because it has a small size, the ∼2.5 μm monodisperse diazoresin-modified silica stationary phase shows ultra-high efficiency compared with the commercial C 18 -silica high-performance liquid chromatography stationary phase with average diameters of ∼5 μm. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fast and simultaneous determination of 12 polyphenols in apple peel and pulp by using chemometrics-assisted high-performance liquid chromatography with diode array detection.

PubMed

Wang, Tong; Wu, Hai-Long; Xie, Li-Xia; Zhu, Li; Liu, Zhi; Sun, Xiao-Dong; Xiao, Rong; Yu, Ru-Qin

2017-04-01

In this work, a smart chemometrics-enhanced strategy, high-performance liquid chromatography, and diode array detection coupled with second-order calibration method based on alternating trilinear decomposition algorithm was proposed to simultaneously quantify 12 polyphenols in different kinds of apple peel and pulp samples. The proposed strategy proved to be a powerful tool to solve the problems of coelution, unknown interferences, and chromatographic shifts in the process of high-performance liquid chromatography analysis, making it possible for the determination of 12 polyphenols in complex apple matrices within 10 min under simple conditions of elution. The average recoveries with standard deviations, and figures of merit including sensitivity, selectivity, limit of detection, and limit of quantitation were calculated to validate the accuracy of the proposed method. Compared to the quantitative analysis results from the classic high-performance liquid chromatography method, the statistical and graphical analysis showed that our proposed strategy obtained more reliable results. All results indicated that our proposed method used in the quantitative analysis of apple polyphenols was an accurate, fast, universal, simple, and green one, and it was expected to be developed as an attractive alternative method for simultaneous determination of multitargeted analytes in complex matrices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Methods of analysis by the U.S. Geological Survey Organic Geochemistry Research Group; determination of chloroacetanilide herbicide metabolites in water using high-performance liquid chromatography-diode array detection and high-performance liquid chromatography/mass spectrometry

USGS Publications Warehouse

Zimmerman, L.R.; Hostetler, K.A.; Thurman, E.M.

2000-01-01

Analytical methods using high-performance liquid chromatography-diode array detection (HPLC-DAD) and high-performance liquid chromatography/mass spectrometry (HPLC/MS) were developed for the analysis of the following chloroacetanilide herbicide metabolites in water: acetochlor ethanesulfonic acid (ESA), acetochlor oxanilic acid (OXA), alachlor ESA, alachlor OXA, metolachlor ESA, and metolachlor OXA. Good precision and accuracy were demonstrated for both the HPLC-DAD and HPLC/MS methods in reagent water, surface water, and ground water. The mean HPLC-DAD recoveries of the chloroacetanilide herbicide metabolites from water samples spiked at 0.25, 0.50, and 2.0 mg/L (micrograms per liter) ranged from 84 to 112 percent, with relative standard deviations of 18 percent or less. The mean HPLC/MS recoveries of the metabolites from water samples spiked at 0.05, 0.20, and 2.0 mg/L ranged from 81 to 125 percent, with relative standard deviations of 20 percent or less. The limit of quantitation (LOQ) for all metabolites using the HPLC-DAD method was 0.20 mg/L, whereas the LOQ using the HPLC/MS method was 0.05 mg/L. These metabolite-determination methods are valuable for acquiring information about water quality and the fate and transport of the parent chloroacetanilide herbicides in water.

Determination of chloroacetanilide herbicide metabolites in water using high-performance liquid chromatography-diode array detection and high-performance liquid chromatography/mass spectrometry

USGS Publications Warehouse

Hostetler, K.A.; Thurman, E.M.

2000-01-01

Analytical methods using high-performance liquid chromatography-diode array detection (HPLC-DAD) and high-performance liquid chromatography/mass spectrometry (HPLC/MS) were developed for the analysis of the following chloroacetanilide herbicide metabolites in water: alachlor ethanesulfonic acid (ESA); alachlor oxanilic acid; acetochlor ESA; acetochlor oxanilic acid; metolachlor ESA; and metolachlor oxanilic acid. Good precision and accuracy were demonstrated for both the HPLC-DAD and HPLC/MS methods in reagent water, surface water, and ground water. The average HPLC-DAD recoveries of the chloroacetanilide herbicide metabolites from water samples spiked at 0.25, 0.5 and 2.0 ??g/l ranged from 84 to 112%, with relative standard deviations of 18% or less. The average HPLC/MS recoveries of the metabolites from water samples spiked at 0.05, 0.2 and 2.0 ??g/l ranged from 81 to 118%, with relative standard deviations of 20% or less. The limit of quantitation (LOQ) for all metabolites using the HPLC-DAD method was 0.20 ??g/l, whereas the LOQ using the HPLC/MS method was at 0.05 ??g/l. These metabolite-determination methods are valuable for acquiring information about water quality and the fate and transport of the parent chloroacetanilide herbicides in water. Copyright (C) 2000 Elsevier Science B.V.

Screening antiallergic components from Carthamus tinctorius using rat basophilic leukemia 2H3 cell membrane chromatography combined with high-performance liquid chromatography and tandem mass spectrometry.

PubMed

Han, Shengli; Huang, Jing; Cui, Ronghua; Zhang, Tao

2015-02-01

Carthamus tinctorius, used in traditional Chinese medicine, has many pharmacological effects, such as anticoagulant effects, antioxidant effects, antiaging effects, regulation of gene expression, and antitumor effects. However, there is no report on the antiallergic effects of the components in C. tinctorius. In the present study, we investigated the antiallergic components of C. tinctorius and its mechanism of action. A rat basophilic leukemia 2H3/cell membrane chromatography coupled online with high-performance liquid chromatography and tandem mass spectrometry method was developed to screen antiallergic components from C. tinctorius. The screening results showed that Hydroxysafflor yellow A, from C. tinctorius, was the targeted component that retained on the rat basophilic leukemia 2H3/cell membrane chromatography column. We measured the amount of β-hexosaminidase and histamine released in mast cells and the key markers of degranulation. The release assays showed that Hydroxysafflor yellow A could attenuate the immunoglobulin E induced release of allergic cytokines without affecting cell viability from 1.0 to 50.0 μM. In conclusion, the established rat basophilic leukemia 2H3 cell membrane chromatography coupled with online high-performance liquid chromatography and tandem mass spectrometry method successfully screened and identified Hydroxysafflor yellow A from C. tinctorius as a potential antiallergic component. Pharmacological analysis elucidated that Hydroxysafflor yellow A is an effective natural component for inhibiting immunoglobulin E-antigen-mediated degranulation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ionic Liquids in HPLC and CE: A Hope for Future.

PubMed

Ali, Imran; Suhail, Mohd; Sanagi, Mohd Marsin; Aboul-Enein, Hassan Y

2017-07-04

The ionic liquids (ILs) are salts with melting points below 100°C. These are called as ionic fluids, ionic melts, liquid electrolytes, fused salts, liquid salts, ionic glasses, designer solvents, green solvents and solvents of the future. These have a wide range of applications, including medical, pharmaceutical and chemical sciences. Nowadays, their use is increasing greatly in separation science, especially in chromatography and capillary electrophoresis due to their remarkable properties. The present article describes the importance of ILs in high-performance liquid chromatography and capillary electrophoresis. Efforts were also made to highlight the future expectations of ILs.

State-of-the art of selective detection and identification of I-, Br-, Cl-, and F-containing compounds in gas chromatography and liquid chromatography.

PubMed

Brede, Cato; Pedersen-Bjergaard, Stig

2004-09-24

This review article presents an overview of halogen-specific detection in gas chromatography (GC) and liquid chromatography (LC). Attention is primarily focused on the use of plasma emission spectroscopy and plasma mass spectrometry as detectors, but other halogen-selective detection principles are also mentioned. Different instrumental configurations are discussed both with respect to technical set-up and performance, the principal reasons for halogen-selective detection are highlighted, and recent applications are reviewed from areas such as environmental chemistry, petroleum characterization, and drug analysis.

Identification of chemical components in Baidianling Capsule based on gas chromatography-mass spectrometry and high-performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry.

PubMed

Wu, Wenying; Chen, Yu; Wang, Binjie; Sun, Xiaoyang; Guo, Ping; Chen, Xiaohui

2017-08-01

Baidianling Capsule, which is made from 16 Chinese herbs, has been widely used for treating vitiligo clinically. In this study, the sensitive and rapid method has been developed for the analysis of chemical components in Baidianling Capsule by gas chromatography-mass spectrometry in combination with retention indices and high-performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry. Firstly, a total of 110 potential volatile compounds obtained from different extraction procedures including alkanes, alkenes, alkynes, ketones, ethers, aldehydes, alcohols, phenols, organic acids, esters, furans, pyrrole, acid amides, heterocycles, and oxides were detected from Baidianling Capsule by gas chromatography-mass spectrometry, of which 75 were identified by mass spectrometry in combination with the retention index. Then, a total of 124 components were tentatively identified by high-performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry. Fifteen constituents from Baidianling Capsule were accurately identified by comparing the retention times with those of reference compounds, others were identified by comparing the retention times and mass spectrometry data, as well as retrieving the reference literature. This study provides a practical strategy for rapidly screening and identifying the multiple constituents of a complex traditional Chinese medicine. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

75 FR 22240 - Cyprodinil; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-28

... chromatography with ultraviolet detector (HPLC/UV)) is available to enforce the tolerance expression on plant commodities. In addition, a high performance liquid chromatography with mass spectrometry (HPLC/MS) method...

Microwave-immobilized polybutadiene stationary phase for reversed-phase high-performance liquid chromatography.

PubMed

Lopes, Nilva P; Collins, Kenneth E; Jardim, Isabel C S F

2004-03-19

Polybutadiene (PBD) has been immobilized on high-performance liquid chromatography (HPLC) silica by microwave radiation at various power levels (52-663 W) and actuation times (3-60 min). Columns prepared from these reversed-phase HPLC materials, as well as from similar non-irradiated materials, were tested with standard sample mixtures and characterized by elemental analysis (%C) and infrared spectroscopy. A microwave irradiation of 20 min at 663 W gives a layer of immobilized PBD that presented good performance. Longer irradiation times give thicker immobilized layers having less favorable chromatographic properties.

Determination of chlorophenols in honey samples using in-situ ionic liquid-dispersive liquid-liquid microextraction as a pretreatment method followed by high-performance liquid chromatography.

PubMed

Fan, Chen; Li, Nai; Cao, Xueli

2015-05-01

In-situ ionic liquid-dispersive liquid-liquid microextraction (IL-DLLME) method was developed as a pretreatment method for the detection of six chlorophenols (CPs) in honey samples. The hydrophobic ionic liquid [C4MIM][NTf2], formed in-situ by the hydrophilic ionic liquid [C4MIM][BF4] and the ion exchange reagent LiNTf2 was used as the microextractant solvent of CPs from honey sample. Then the enriched analytes were back-extracted into 40 μL of 0.14 M NaOH solution and finally subjected to analysis by high-performance liquid chromatography. The method showed low limit of detection of CPs, 0.8-3.2 μg/L and high enrichment factor, 34-65 with the recoveries range from 91.60% to 114.33%. The method is simple, rapid, environmentally friendly and with high extraction efficiency. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Collaborative trial validation study of two methods, one based on high performance liquid chromatography-tandem mass spectrometry and on gas chromatography-mass spectrometry for the determination of acrylamide in bakery and potato products.

PubMed

Wenzl, Thomas; Karasek, Lubomir; Rosen, Johan; Hellenaes, Karl-Erik; Crews, Colin; Castle, Laurence; Anklam, Elke

2006-11-03

A European inter-laboratory study was conducted to validate two analytical procedures for the determination of acrylamide in bakery ware (crispbreads, biscuits) and potato products (chips), within a concentration range from about 20 microg/kg to about 9000 microgg/kg. The methods are based on gas chromatography-mass spectrometry (GC-MS) of the derivatised analyte and on high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) of native acrylamide. Isotope dilution with isotopically labelled acrylamide was an integral part of both methods. The study was evaluated according to internationally accepted guidelines. The performance of the HPLC-MS/MS method was found to be superior to that of the GC-MS method and to be fit-for-the-purpose.

Fingerprinting profile of polysaccharides from Lycium barbarum using multiplex approaches and chemometrics

USDA-ARS?s Scientific Manuscript database

Techniques including ultraviolet-visible spectra (UV), high performance size-exclusion chromatography (HPSEC), fourier-transform infrared spectroscopy (FT-IR) and pre-column derivatization high-performance liquid chromatography (PCD-HPLC) were used in the fingerprinting analysis of Lycium barbarum p...

Recent applications of hydrophilic interaction liquid chromatography in pharmaceutical analysis.

PubMed

Zhang, Qian; Yang, Feng-Qing; Ge, Liya; Hu, Yuan-Jia; Xia, Zhi-Ning

2017-01-01

Hydrophilic interaction liquid chromatography, an alternative liquid chromatography mode, is of particular interest in separating hydrophilic and polar ionic compounds. Compared with traditional liquid chromatography techniques, hydrophilic interaction liquid chromatography offers specific advantages mainly including: (1) relatively green and water-soluble mobile phase composition, which enhances the solubility of hydrophilic and polar ionic compounds; (2) no need for ion-pairing reagents and high content of organic solvent, which benefits mass spectrometry detection; (3) high orthogonality to reverse-phase liquid chromatography, well adapted to two-dimensional liquid chromatography for complicated samples. Therefore, hydrophilic interaction liquid chromatography has been rapidly developed in many areas over the past decades. This review summarizes the recent progress (from 2012 to July 2016) of hydrophilic interaction liquid chromatography in pharmaceutical analysis, with the focus on detecting chemical drugs in various matrices, charactering active compounds of natural products and assessing biotherapeutics through typical structure unit. Moreover, the retention mechanism and behavior of analytes in hydrophilic interaction liquid chromatography as well as some novel hydrophilic interaction liquid chromatography columns used for pharmaceutical analysis are also described. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pressurized planar electrochromatography, high-performance thin-layer chromatography and high-performance liquid chromatography--comparison of performance.

PubMed

Płocharz, Paweł; Klimek-Turek, Anna; Dzido, Tadeusz H

2010-07-16

Kinetic performance, measured by plate height, of High-Performance Thin-Layer Chromatography (HPTLC), High-Performance Liquid Chromatography (HPLC) and Pressurized Planar Electrochromatography (PPEC) was compared for the systems with adsorbent of the HPTLC RP18W plate from Merck as the stationary phase and the mobile phase composed of acetonitrile and buffer solution. The HPLC column was packed with the adsorbent, which was scrapped from the chromatographic plate mentioned. An additional HPLC column was also packed with adsorbent of 5 microm particle diameter, C18 type silica based (LiChrosorb RP-18 from Merck). The dependence of plate height of both HPLC and PPEC separating systems on flow velocity of the mobile phase and on migration distance of the mobile phase in TLC system was presented applying test solute (prednisolone succinate). The highest performance, amongst systems investigated, was obtained for the PPEC system. The separation efficiency of the systems investigated in the paper was additionally confirmed by the separation of test component mixture composed of six hormones. 2010 Elsevier B.V. All rights reserved.

Study of the in vitro metabolism of TJ0711 using ultra high performance liquid chromatography with quadrupole time-of-flight and ultra fast liquid chromatography with quadrupole linear ion trap mass spectrometry.

PubMed

Hu, Lei; Lv, Zhenhua; Li, Gao; Xu, Xiaolong; Zhang, Chenghao; Cao, Peng; Huang, Jiangeng; Si, Luqin

2015-06-01

TJ0711 (1-[4-(2-methoxyethyl)phenoxy]-3-[2-(2-methoxyphenoxy)ethylamino]-2-propanol) is a novel β-adrenoreceptor blocker with vasodilating activity. The aim of this study was to investigate the in vitro metabolic properties of TJ0711 from both qualitative and quantitative aspects using mouse, rat, dog, and human liver microsomes as well as rat hepatocytes. Two modern liquid chromatography with tandem mass spectrometry systems, ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry and ultra fast liquid chromatography with quadrupole linear ion trap mass spectrometry, were utilized for the analysis. To better characterize the metabolic pathways of TJ0711, two major metabolites were incubated under the same conditions as that for TJ0711. TJ0711 was extensively metabolized in vitro, and a total of 34 metabolites, including 19 phase I and 15 phase II metabolites, were identified. Similar metabolite profiles were observed among species, and demethylation, hydroxylation, carboxylic acid formation, and glucuronidation were proposed as the major metabolic routes. Significant interspecies differences were observed in the metabolic stability studies of TJ0711. Furthermore, gender differences were significant in mice, rats, and dogs, but were negligible in humans. The valuable information provided in this work will be useful in planning and interpreting further pharmacokinetic, in vivo metabolism and toxicological studies of this novel β-blocker. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of Mixed Culture Growth Conditions on the Cellular Fatty Acids of Streptococci (Analyzed by High Performance Liquid Chromatography),

DTIC Science & Technology

1980-10-16

mixed culture with Streptococcus S mutans , Streptococcus singuis Staphylococcus aureus,*and Escheric ia coi 1 - sA -DoWed n o quaI It atfI ve -c nah...of both S. mutans and S. scnguis. I 4 |I KEY WORDS: Fatty Acids . High Performance Liquid Chromatography Mixed Bacterial Cultures Streptococcus sal...AND METHODS Streptococcus mutans (ATCC 25175), Streptococcus sanguis (ATCC 10557), Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922

High-performance liquid chromatography analysis of plant saponins: An update 2005-2010

PubMed Central

Negi, Jagmohan S.; Singh, Pramod; Pant, Geeta Joshi Nee; Rawat, M. S. M.

2011-01-01

Saponins are widely distributed in plant kingdom. In view of their wide range of biological activities and occurrence as complex mixtures, saponins have been purified and separated by high-performance liquid chromatography using reverse-phase columns at lower wavelength. Mostly, saponins are not detected by ultraviolet detector due to lack of chromophores. Electrospray ionization mass spectrometry, diode array detector , evaporative light scattering detection, and charged aerosols have been used for overcoming the detection problem of saponins. PMID:22303089

The separation of leukotrienes and hydroxyeicosatetraenoic acid metabolites of arachidonic acid by high performance liquid chromatography (HPLC).

PubMed

Osborne, D J; Peters, B J; Meade, C J

1983-11-01

The following high performance liquid chromatography system was found suitable for separating most lipoxygenase metabolites of arachidonic acid: Techsphere 5-C18 column, eluting solvent methanol:water:acetic acid (65:35:0.06 v/v), pH 5.3. Comparisons with other packing materials and solvent systems are described. The method could be used to identify lipoxygenase products released from mouse macrophage cells stimulated with gamma-hexachlorocyclohexane. Detection limits between 1 and 10 ng were obtained.

RECENT ADVANCES IN ULTRA-HIGH PERFORMANCE LIQUID CHROMATOGRAPHY FOR THE ANALYSIS OF TRADITIONAL CHINESE MEDICINE

PubMed Central

Huang, Huilian; Liu, Min; Chen, Pei

2014-01-01

Traditional Chinese medicine has been widely used for the prevention and treatment of various diseases for thousands of years in China. Ultra-high performance liquid chromatography (UHPLC) is a relatively new technique offering new possibilities. This paper reviews recent developments in UHPLC in the separation and identification, fingerprinting, quantification, and metabolism of traditional Chinese medicine. Recently, the combination of UHPLC with MS has improved the efficiency of the analysis of these materials. PMID:25045170

Hydrocarbon group type determination in jet fuels by high performance liquid chromatography

NASA Technical Reports Server (NTRS)

Antoine, A. C.

1977-01-01

Thirty-two jet and diesel fuel samples of varying chemical composition and physical properties were prepared from oil shale and coal syncrudes. Hydrocarbon types in these samples were determined by a fluorescent indicator adsorption analysis, and the results from three laboratories are presented and compared. Two methods of rapid high performance liquid chromatography were used to analyze some of the samples, and these results are also presented and compared. Two samples of petroleum-based Jet A fuel are similarly analyzed.

Observation of T-2 and HT-2 glucosides from Fusarium sporotrichioides by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS)

USDA-ARS?s Scientific Manuscript database

Cultures of Fusarium sporotrichioides were extracted and subjected to evaluation by high performance liquid chromatography – tandem mass spectrometry (LC-MS/MS). Along with the expected T-2 and HT-2 toxins, compounds 162 m/z higher than the toxins were observed. Fragmentation behavior of the larger ...

Surface-bonded ionic liquid stationary phases in high-performance liquid chromatography--a review.

PubMed

Pino, Verónica; Afonso, Ana M

2012-02-10

Ionic liquids (ILs) are a class of ionic, nonmolecular solvents which remain in liquid state at temperatures below 100°C. ILs possess a variety of properties including low to negligible vapor pressure, high thermal stability, miscibility with water or a variety of organic solvents, and variable viscosity. IL-modified silica as novel high-performance liquid chromatography (HPLC) stationary phases have attracted considerable attention for their differential behavior and low free-silanol activity. Indeed, around 21 surface-confined ionic liquids (SCIL) stationary phases have been developed in the last six years. Their chromatographic behavior has been studied, and, despite the presence of a positive charge on the stationary phase, they showed considerable promise for the separation of neutral solutes (not only basic analytes), when operated in reversed phase mode. This aspect points to the potential for truly multimodal stationary phases. This review attempts to summarize the state-of-the-art about SCIL phases including their preparation, chromatographic behavior, and analytical performance. Copyright © 2011 Elsevier B.V. All rights reserved.

Dispersive liquid-liquid microextraction based on solidification of floating organic droplet followed by high-performance liquid chromatography with ultraviolet detection and liquid chromatography-tandem mass spectrometry for the determination of triclosan and 2,4-dichlorophenol in water samples.

PubMed

Zheng, Cao; Zhao, Jing; Bao, Peng; Gao, Jin; He, Jin

2011-06-24

A novel, simple and efficient dispersive liquid-liquid microextraction based on solidification of floating organic droplet (DLLME-SFO) technique coupled with high-performance liquid chromatography with ultraviolet detection (HPLC-UV) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the determination of triclosan and its degradation product 2,4-dichlorophenol in real water samples. The extraction solvent used in this work is of low density, low volatility, low toxicity and proper melting point around room temperature. The extractant droplets can be collected easily by solidifying it at a lower temperature. Parameters that affect the extraction efficiency, including type and volume of extraction solvent and dispersive solvent, salt effect, pH and extraction time, were investigated and optimized in a 5 mL sample system by HPLC-UV. Under the optimum conditions (extraction solvent: 12 μL of 1-dodecanol; dispersive solvent: 300 of μL acetonitrile; sample pH: 6.0; extraction time: 1 min), the limits of detection (LODs) of the pretreatment method combined with LC-MS/MS were in the range of 0.002-0.02 μg L(-1) which are lower than or comparable with other reported approaches applied to the determination of the same compounds. Wide linearities, good precisions and satisfactory relative recoveries were also obtained. The proposed technique was successfully applied to determine triclosan and 2,4-dichlorophenol in real water samples. Copyright © 2011 Elsevier B.V. All rights reserved.

High-performance liquid chromatography analysis methods developed for quantifying enzymatic esterification of flavonoids in ionic liquids.

PubMed

Lue, Bena-Marie; Guo, Zheng; Xu, Xuebing

2008-07-11

Methods using reversed-phase high-performance liquid chromatography (RP-HPLC) with ELSD were investigated to quantify enzymatic reactions of flavonoids with fatty acids in the presence of diverse room temperature ionic liquids (RTILs). A buffered salt (preferably triethylamine-acetate) was found essential for separation of flavonoids from strongly polar RTILs, whereby RTILs were generally visible as two major peaks identified based on an ion-pairing/exchanging hypothesis. C8 and C12 stationary phases were optimal while mobile phase pH (3-7) had only a minor influence on separation. The method developed was successfully applied for primary screening of RTILs (>20), with in depth evaluation of substrates in 10 RTILs, for their evaluation as reaction media.

Determination of boldenone sulfoconjugate and related steroid sulfates in equine urine by high-performance liquid chromatography/tandem mass spectrometry.

PubMed

Weidolf, L O; Lee, E D; Henion, J D

1988-03-01

Sulfoconjugated anabolic steroids were separated by micro-bore high-performance liquid chromatography. The eluent was introduced into the atmospheric pressure ion source of the triple-quadrupole mass spectrometer via an ion spray liquid chromatograph/mass spectrometer interface operated in the negative ion mode. The limit of detection was 10 pg on-column by selected ion monitoring of the molecular ion and the response increased linearly over a concentration range of 2.4 orders of magnitude. Following work-up by a liquid-solid extraction procedure of equine urine samples, full-scan daughter ion spectra of boldenone sulfate could be obtained up to 17 days after a therapeutic dose of boldenone undecylenate to a horse.

Determination of MDMA, MDEA and MDA in urine by high performance liquid chromatography with fluorescence detection.

PubMed

da Costa, José Luiz; da Matta Chasin, Alice Aparecida

2004-11-05

This paper describes the development and validation of analytical methodology for the determination of the use of MDMA, MDEA and MDA in urine. After a simple liquid extraction, the analyses were carried out on a high performance liquid chromatography (HPLC) in an octadecyl column, with fluorescence detection. The mobile phase using a sodium dodecyl sulfate ion-pairing reagent allows good separation and efficiency. The method showed good linearity and precision. Recovery was between 85 and 102% and detection limits were 10, 15 and 20 ng/ml for MDA, MDMA and MDEA, respectively. No interfering substances were detected with fluorescence detection.

Recent progress of task-specific ionic liquids in chiral resolution and extraction of biological samples and metal ions.

PubMed

Wu, Datong; Cai, Pengfei; Zhao, Xiaoyong; Kong, Yong; Pan, Yuanjiang

2018-01-01

Ionic liquids have been functionalized for modern applications. The functional ionic liquids are also called task-specific ionic liquids. Various task-specific ionic liquids with certain groups have been constructed and exploited widely in the field of separation. To take advantage of their properties in separation science, task-specific ionic liquids are generally used in techniques such as liquid-liquid extraction, solid-phase extraction, gas chromatography, high-performance liquid chromatography, and capillary electrophoresis. This review mainly covers original research papers published in the last five years, and we will focus on task-specific ionic liquids as the chiral selectors in chiral resolution and as extractant or sensor for biological samples and metal ion purification. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Diesel Engine Air Emissions Reduction Technologies

DTIC Science & Technology

2010-04-01

Hour GC/MS Gas Chromatography /Mass Spectroscopy GC/FID Gas Chromatography /Flame Ionization Detector g/mile Gram per Mile HAP Hazardous Air...Pollutant HC Hydrocarbon HPLC/UV High Performance Liquid Chromatography / Ultraviolet KPa Kilo-Pascals NDIR Non Dispersive Infrared... Chromatography (GC) where the samples were collected on DNPH cartridges. Portable versions of these instruments were available and employed for

Effects of liquid chromatography mobile phases and buffer salts on phosphorus inductively coupled plasma atomic emission and mass spectrometries utilizing ultrasonic nebulization and membrane desolvation.

PubMed

Carr, John E; Kwok, Kaho; Webster, Gregory K; Carnahan, Jon W

2006-01-23

Atomic spectrometry, specifically inductively coupled plasma atomic emission spectrometry (ICP-AES) and mass spectrometry (ICP-MS) show promise for heteroatom-based detection of pharmaceutical compounds. The combination of ultrasonic nebulization (USN) with membrane desolvation (MD) greatly enhances detection limits with these approaches. Because pharmaceutical analyses often incorporate liquid chromatography, the study herein was performed to examine the effects of solvent composition on the analytical behaviors of these approaches. The target analyte was phosphorus, introduced as phosphomycin. AES response was examined at the 253.7 nm atom line and mass 31 ions were monitored for the MS experiments. With pure aqueous solutions, detection limits of 5 ppb (0.5 ng in 0.1 mL injection volumes) were obtained with ICP-MS. The ICP-AES detection limit was 150 ppb. Solvent compositions were varied from 0 to 80% organic (acetonitrile and methanol) with nine buffers at concentrations typically used in liquid chromatography. In general, solvents and buffers had statistically significant, albeit small, effects on ICP-AES sensitivities. A few exceptions occurred in cases where typical liquid chromatography buffer concentrations produced higher mass loadings on the plasma. Indications are that isocratic separations can be reliably performed. Within reasonable accuracy tolerances, it appears that gradient chromatography can be performed without the need for signal response normalization. Organic solvent and buffer effects were more significant with ICP-MS. Sensitivities varied significantly with different buffers and organic solvent content. In these cases, gradient chromatography will require careful analytical calibration as solvent and buffer content is varied. However, for most buffer and solvent combinations, signal and detection limits are only moderately affected. Isocratic separations and detection are feasible.

Highly efficient peptide separations in proteomics. Part 2: bi- and multidimensional liquid-based separation techniques.

PubMed

Sandra, Koen; Moshir, Mahan; D'hondt, Filip; Tuytten, Robin; Verleysen, Katleen; Kas, Koen; François, Isabelle; Sandra, Pat

2009-04-15

Multidimensional liquid-based separation techniques are described for maximizing the resolution of the enormous number of peptides generated upon tryptic digestion of proteomes, and hence, reduce the spatial and temporal complexity of the sample to a level that allows successful mass spectrometric analysis. This review complements the previous contribution on unidimensional high performance liquid chromatography (HPLC). Both chromatography and electrophoresis will be discussed albeit with reversed-phase HPLC (RPLC) as the final separation dimension prior to MS analysis.

Liquid chromatography and supercritical fluid chromatography as alternative techniques to gas chromatography for the rapid screening of anabolic agents in urine.

PubMed

Desfontaine, Vincent; Nováková, Lucie; Ponzetto, Federico; Nicoli, Raul; Saugy, Martial; Veuthey, Jean-Luc; Guillarme, Davy

2016-06-17

This work describes the development of two methods involving supported liquid extraction (SLE) sample treatment followed by ultra-high performance liquid chromatography or ultra-high performance supercritical fluid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS and UHPSFC-MS/MS) for the screening of 43 anabolic agents in human urine. After evaluating different stationary phases, a polar-embedded C18 and a diol columns were selected for UHPLC-MS/MS and UHPSFC-MS/MS, respectively. Sample preparation, mobile phases and MS conditions were also finely tuned to achieve highest selectivity, chromatographic resolution and sensitivity. Then, the performance of these two methods was compared to the reference routine procedure for steroid analyses in anti-doping laboratories, which combines liquid-liquid extraction (LLE) followed by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). For this purpose, urine samples spiked with the compounds of interest at five different concentrations were analyzed using the three analytical platforms. The retention and selectivity of the three techniques were very different, ensuring a good complementarity. However, the two new methods displayed numerous advantages. The overall procedure was much faster thanks to high throughput SLE sample treatment using 48-well plates and faster chromatographic analysis. Moreover, the highest sensitivity was attained using UHPLC-MS/MS with 98% of the doping agents detected at the lowest concentration level (0.1ng/mL), against 76% for UHPSFC-MS/MS and only 14% for GC-MS/MS. Finally, the weakest matrix effects were obtained with UHPSFC-MS/MS with 76% of the analytes displaying relative matrix effect between -20 and 20%, while the GC-MS/MS reference method displayed very strong matrix effects (over 100%) for all of the anabolic agents. Copyright © 2016 Elsevier B.V. All rights reserved.

Triticonazole enantiomers: Separation by supercritical fluid chromatography and the effect of the chromatographic conditions.

PubMed

He, Jianfeng; Fan, Jun; Yan, Yilun; Chen, Xiaodong; Wang, Tai; Zhang, Yaomou; Zhang, Weiguang

2016-11-01

Enantiomeric pairs of triticonazole have been successfully separated by supercritical fluid chromatography coupled with a tris(3,5-dimethylphenylcarbamoyl) cellulose-coated chiral stationary phase in this work. The effects of co-solvent, dissolution solvent, flow rate, backpressure, and column temperature have been studied in detail with respect to retention, selectivity, and resolution of triticonazole. As indicated, the co-solvents mostly affected the retention factors and resolution, due to the different molecular structure and polarity. In addition, the dissolution solvents, namely, chloromethanes and alcohols, have been also important for enantioseparation because of the different interaction with stationary phase. Higher flow rate and backpressure led to faster elution of the triticonazole molecules, and the change of column temperature showed slight effect on the resolution of triticonazole racemate. Moreover, a comparative separation experiment between supercritical fluid chromatography and high performance liquid chromatography revealed that chiral supercritical fluid chromatography gave the 3.5 times value of R s /t R2 than high performance liquid chromatography, which demonstrated that supercritical fluid chromatography had much higher separation efficiency. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous determination of kasugamycin and validamycin-A residues in cereals by consecutive solid-phase extraction combined with liquid chromatography-tandem mass spectrometry.

PubMed

Zhang, Hong; Wang, Chenchen; Li, Huidong; Nie, Yan; Fang, Liping; Chen, Zilei

2018-03-01

Two polar aminoglycosides, kasugamycin and validamycin-A, were determined in cereals (brown rice, wheat and corn) by high-performance liquid chromatography-tandem mass spectrometry. The analytes were extracted from samples using methanol and water (70:30, v/v) at pH 5.5, purified using both a hydrophilic-hydrophobic-balanced cartridge and a strong cation-exchange cartridge, and then analysed using multiple reaction monitoring in positive electrospray ionisation mode with a special ReproSil 100 C 18 high-performance liquid chromatography column. This newly proposed method yielded good sensitivity and excellent chromatographic performance. The limits of quantification for kasugamycin and validamycin-A were 4.1 µg/kg and 1.0 µg/kg, respectively. The recoveries for both compounds at three fortification levels (4, 100 and 500 µg/kg for kasugamycin; 1, 10 and 100 µg/kg for validamycin-A) ranged from 75% to 110%, and the relative standard deviations were below 15%.

New support for high-performance liquid chromatography based on silica coated with alumina particles.

PubMed

Silveira, José Leandro R; Dib, Samia R; Faria, Anizio M

2014-01-01

A new material based on silica coated with alumina nanoparticles was proposed for use as a chromatographic support for reversed-phase high-performance liquid chromatography. Alumina nanoparticles were synthesized by a sol-gel process in reversed micelles composed of sodium bis(2-ethylhexyl)sulfosuccinate, and the support material was formed by the self-assembly of alumina layers on silica spheres. Spectroscopic and (29)Si nuclear magnetic resonance results showed evidence of chemical bonds between the alumina nanoparticles and the silica spheres, while morphological characterizations showed that the aluminized silica maintained the morphological properties of silica desired for chromatographic purposes after alumina incorporation. Stability studies indicated that bare silica showed high dissolution (~83%), while the aluminized silica remained practically unchanged (99%) after passing one liter of the alkaline mobile phase, indicating high stability under alkaline conditions. The C18 bonded aluminized silica phase showed great potential for use in high-performance liquid chromatography to separate basic molecules in the reversed-phase mode.

Quantitation of sugar content in pyrolysis liquids after acid hydrolysis using high-performance liquid chromatography without neutralization.

PubMed

Johnston, Patrick A; Brown, Robert C

2014-08-13

A rapid method for the quantitation of total sugars in pyrolysis liquids using high-performance liquid chromatography (HPLC) was developed. The method avoids the tedious and time-consuming sample preparation required by current analytical methods. It is possible to directly analyze hydrolyzed pyrolysis liquids, bypassing the neutralization step usually required in determination of total sugars. A comparison with traditional methods was used to determine the validity of the results. The calibration curve coefficient of determination on all standard compounds was >0.999 using a refractive index detector. The relative standard deviation for the new method was 1.13%. The spiked sugar recoveries on the pyrolysis liquid samples were between 104 and 105%. The research demonstrates that it is possible to obtain excellent accuracy and efficiency using HPLC to quantitate glucose after acid hydrolysis of polymeric and oligomeric sugars found in fast pyrolysis bio-oils without neutralization.

Fast and sensitive analysis of beta blockers by ultra-high-performance liquid chromatography coupled with ultra-high-resolution TOF mass spectrometry.

PubMed

Tomková, Jana; Ondra, Peter; Kocianová, Eva; Václavík, Jan

2017-07-01

This paper presents a method for the determination of acebutolol, betaxolol, bisoprolol, metoprolol, nebivolol and sotalol in human serum by liquid-liquid extraction and ultra-high-performance liquid chromatography coupled with ultra-high-resolution TOF mass spectrometry. After liquid-liquid extraction, beta blockers were separated on a reverse-phase analytical column (Acclaim RS 120; 100 × 2.1 mm, 2.2 μm). The total run time was 6 min for each sample. Linearity, limit of detection, limit of quantification, matrix effects, specificity, precision, accuracy, recovery and sample stability were evaluated. The method was successfully applied to the therapeutic drug monitoring of 108 patients with hypertension. This method was also used for determination of beta blockers in 33 intoxicated patients. Copyright © 2016 John Wiley & Sons, Ltd.

Low Density Solvent-Based Dispersive Liquid-Liquid Microextraction for the Determination of Synthetic Antioxidants in Beverages by High-Performance Liquid Chromatography

PubMed Central

Çabuk, Hasan; Köktürk, Mustafa

2013-01-01

A simple and efficient method was established for the determination of synthetic antioxidants in beverages by using dispersive liquid-liquid microextraction combined with high-performance liquid chromatography with ultraviolet detection. Butylated hydroxy toluene, butylated hydroxy anisole, and tert-butylhydroquinone were the antioxidants evaluated. Experimental parameters including extraction solvent, dispersive solvent, pH of sample solution, salt concentration, and extraction time were optimized. Under optimal conditions, the extraction recoveries ranged from 53 to 96%. Good linearity was observed by the square of correlation coefficients ranging from 0.9975 to 0.9997. The relative standard deviations ranged from 1.0 to 5.2% for all of the analytes. Limits of detection ranged from 0.85 to 2.73 ng mL−1. The method was successfully applied for determination of synthetic antioxidants in undiluted beverage samples with satisfactory recoveries. PMID:23853535

Development of techniques for the analysis of isoflavones in soy foods and nutraceuticals.

PubMed

Dentith, Susan; Lockwood, Brian

2008-05-01

For over 20 years, soy isoflavones have been investigated for their ability to prevent a wide range of cancers and cardiovascular problems, and numerous other disease states. This research is underpinned by the ability of researchers to analyse isoflavones in various forms in a range of raw materials and biological fluids. This review summarizes the techniques recently used in their analysis. The speed of high performance liquid chromatography analysis has been improved, allowing analysis of more samples, and increasing the sensitivity of detection techniques allows quantification of isoflavones down to nanomoles per litre levels in biological fluids. The combination of high-performance liquid chromatography with immunoassay has allowed identification and estimation of low-level soy isoflavones. The use of soy isoflavone supplements has shown an increase in their circulating levels in plasma and urine, aiding investigation of their biological effects. The significance of the metabolite equol has spurned research into new areas, and recently the specific enantiomers have been studied. High-performance liquid chromatography, capillary electrophoresis and gas chromatography are widely used with a range of detection systems. Increasingly, immunoassay is being used because of its high sensitivity and low cost.

Determination of Niacinamide in Lotions and Creams Using Liquid-Liquid Extraction and High-Performance Liquid Chromatography

ERIC Educational Resources Information Center

Usher, Karyn M.; Simmons, Carolyn R.; Keating, Daniel W.; Rossi, Henry F., III

2015-01-01

Chemical separations are an important part of an undergraduate chemistry curriculum. Sophomore students often get experience with liquid-liquid extraction in organic chemistry classes, but liquid-liquid extraction is not as often introduced as a quantitative sample preparation method in honors general chemistry or quantitative analysis classes.…

An evaluation of sucrose as a possible contaminant in e-liquids for electronic cigarettes by hydrophilic interaction liquid chromatography-tandem mass spectrometry.

PubMed

Kubica, Paweł; Wasik, Andrzej; Kot-Wasik, Agata; Namieśnik, Jacek

2014-05-01

The influence of sucrose combustion products on smoking and nicotine addiction is still controversial because the presence of the sucrose may be treated as a source of aldehydes and organic acids. In e-liquids used as refills for electronic cigarettes, which are made primarily of poly(propylene glycol), glycerine and ethanol, sucrose may be present at trace levels, and its impact on mainstream smoke formation, and hence on human health and smoking/nicotine addiction is unknown. An analytical method was developed where high-performance liquid chromatography in hydrophilic interaction liquid chromatography mode and tandem mass spectrometry were used for fast and simple determination of sucrose and other saccharides in e-liquids for electronic cigarettes. Minimal effort was required in the sample preparation step, and satisfactory results were obtained, and the sample matrix had an insignificant impact. The chromatographic separation was done using an Ascentis Express OH5 column (150 mm × 2.1 mm, 2.7 μm). The coefficients of variation for within-day precision for three concentrations were 2.4 %, 1.6 % and 2.3 %, and the between-day coefficients of variation for a single concentration were 2.1 %, 2.5 % and 1.7 % measured on the next 3 days. The detection limit was 0.73 μg/g, and the sucrose content in e-liquids ranged from 0.76 to 72.93 μg/g among 37 samples. Moreover, with the method presented it is possible to determine the presence of other saccharides such as fructose, glucose, maltose and lactose. However, only sucrose was found in all samples of e-liquids. The proposed method is rapid, simple and reliable in terms of high-performance liquid chromatography coupled with tandem mass spectrometry.

Stability behaviour of antiretroviral drugs and their combinations. 5: Characterization of novel degradation products of abacavir sulfate by mass and nuclear magnetic resonance spectrometry.

PubMed

Kurmi, Moolchand; Sahu, Archana; Singh, Saranjit

2017-02-05

In the present study, degradation behaviour of abacavir sulfate was evaluated in solution and solid stress conditions. Solution state studies resulted in formation of eleven degradation products; of which two were also formed on solid stress. The same were separated by high performance liquid chromatography. They were characterized using liquid chromatography-high resolution mass spectrometry, liquid chromatography-multistage mass spectrometry and hydrogen/deuterium exchange mass spectrometry data. Additionally, seven degradation products were isolated and subjected to 1D and 2D nuclear magnetic resonance studies for their structural confirmation. Copyright © 2016 Elsevier B.V. All rights reserved.

Rapid screening, identification, and purification of neuraminidase inhibitors from Lithospermum erythrorhizon Sieb.et Zucc. by ultrafiltration with HPLC-ESI-TOF-MS combined with semipreparative HPLC.

PubMed

Zhang, Minmin; Zhao, Hengqiang; Zhao, Zhiguo; Yan, Huijiao; Lv, Ruimin; Cui, Li; Yuan, Jinpeng; Wang, Daijie; Geng, Yanling; Liu, Daicheng; Wang, Xiao

2016-06-01

We put forward an efficient strategy based on bioassay guidance for the rapid screening, identification, and purification of the neuraminidase inhibitors from traditional Chinese medicines, and apply to the discovery of anti-influenza components from Lithospermiun erythrorhizon Sieb.et Zucc. Ultrafiltration with high-performance liquid chromatography and electrospray ionization time-of-flight mass spectrometry was employed for the rapid screening and preliminarily identification of anti-influenza components from Zicao. Semipreparative high-performance liquid chromatography was used for the rapid separation and purification of the target compounds. NMR spectroscopy, mass spectrometry, and UV spectroscopy were used for further structural identification, and the activity of the compounds was verified by in vitro assay. Five compounds were found to have neuraminidase inhibitory activity by this method. Subsequently, the five compounds were separated by semipreparative high-performance liquid chromatography with the purity over 98% for all of them by high-performance liquid chromatography test. Combined with the NMR spectroscopy, mass spectrometry, and UV spectroscopy data, they were identified as alkannin, acetylalkannin, isobutyrylalkannin, β,β-dimethylacryloylalkannin and isovalerylalkannin. The in vitro assay showed that all five compounds had good neuraminidase inhibitory activities. These results suggested that the method is highly efficient, and it can provide platform and methodology supports for the rapid discovery of anti-influenza active ingredients from complex Chinese herbal medicines. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous determination of phenolic compounds in Equisetum palustre L. by ultra high performance liquid chromatography with tandem mass spectrometry combined with matrix solid-phase dispersion extraction.

PubMed

Wei, Zuofu; Pan, Youzhi; Li, Lu; Huang, Yuyang; Qi, Xiaolin; Luo, Meng; Zu, Yuangang; Fu, Yujie

2014-11-01

A method based on matrix solid-phase dispersion extraction followed by ultra high performance liquid chromatography with tandem mass spectrometry is presented for the extraction and determination of phenolic compounds in Equisetum palustre. This method combines the high efficiency of matrix solid-phase dispersion extraction and the rapidity, sensitivity, and accuracy of ultra high performance liquid chromatography with tandem mass spectrometry. The influential parameters of the matrix solid-phase dispersion extraction were investigated and optimized. The optimized conditions were as follows: silica gel was selected as dispersing sorbent, the ratio of silica gel to sample was selected to be 2:1 (400/200 mg), and 8 mL of 80% methanol was used as elution solvent. Furthermore, a fast and sensitive ultra high performance liquid chromatography with tandem mass spectrometry method was developed for the determination of nine phenolic compounds in E. palustre. This method was carried out within <6 min, and exhibited satisfactory linearity, precision, and recovery. Compared with ultrasound-assisted extraction, the proposed matrix solid-phase dispersion procedure possessed higher extraction efficiency, and was more convenient and time saving with reduced requirements on sample and solvent amounts. All these results suggest that the developed method represents an excellent alternative for the extraction and determination of active components in plant matrices. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simultaneous determination and qualitative analysis of six types of components in Naoxintong capsule by miniaturized matrix solid-phase dispersion extraction coupled with ultra high-performance liquid chromatography with photodiode array detection and quadrupole time-of-flight mass spectrometry.

PubMed

Wang, Huilin; Jiang, Yan; Ding, Mingya; Li, Jin; Hao, Jia; He, Jun; Wang, Hui; Gao, Xiu-Mei; Chang, Yan-Xu

2018-02-03

A simple and effective sample preparation process based on miniaturized matrix solid-phase dispersion was developed for simultaneous determination of phenolic acids (gallic acid, chlorogenic acid, ferulic acid, 3,5-dicaffeoylqunic acid, 1,5-dicaffeoylqunic acid, rosmarinic acid, lithospermic acid, and salvianolic acid B), flavonoids (kaempferol-3-O-rutinoside, calycosin, and formononetin), lactones (ligustilide and butyllidephthalide), monoterpenoids (paeoniflorin), phenanthraquinones (cryptotanshinone), and furans (5-hydroxymethylfurfural) in Naoxintong capsule by ultra high-performance liquid chromatography. The optimized condition was that 25 mg Naoxintong powder was blended homogeneously with 100 mg Florisil PR for 4 min. One milliliter of methanol/water (75:25, v/v) acidified by 0.05% formic acid was selected to elute all components. It was found that the recoveries of the six types of components ranged from 61.36 to 96.94%. The proposed miniaturized matrix solid-phase dispersion coupled with ultra high-performance liquid chromatography was successfully applied to simultaneous determination of the six types of components in Naoxintong capsules. The results demonstrated that the proposed miniaturized matrix solid-phase dispersion coupled with ultra high-performance liquid chromatography could be used as an environmentally friendly tool for the extraction and determination of multiple bioactive components in natural products. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-performance liquid chromatography coupled with tandem mass spectrometry technology in the analysis of Chinese Medicine Formulas: A bibliometric analysis (1997-2015).

PubMed

He, Xi-Ran; Li, Chun-Guang; Zhu, Xiao-Shu; Li, Yuan-Qing; Jarouche, Mariam; Bensoussan, Alan; Li, Ping-Ping

2017-01-01

There is a recognized challenge in analyzing traditional Chinese medicine formulas because of their complex chemical compositions. The application of modern analytical techniques such as high-performance liquid chromatography coupled with a tandem mass spectrometry has improved the characterization of various compounds from traditional Chinese medicine formulas significantly. This study aims to conduct a bibliometric analysis to recognize the overall trend of high-performance liquid chromatography coupled with tandem mass spectrometry approaches in the analysis of traditional Chinese medicine formulas, its significance and possible underlying interactions between individual herbs in these formulas. Electronic databases were searched systematically, and the identified studies were collected and analyzed using Microsoft Access 2010, Graph Pad 5.0 software and Ucinet software package. 338 publications between 1997 and 2015 were identified, and analyzed in terms of annual growth and accumulated publications, top journals, forms of traditional Chinese medicine preparations and highly studied formulas and single herbs, as well as social network analysis of single herbs. There is a significant increase trend in using high-performance liquid chromatography coupled with tandem mass spectrometry related techniques in analysis of commonly used forms of traditional Chinese medicine formulas in the last 3 years. Stringent quality control is of great significance for the modernization and globalization of traditional Chinese medicine, and this bibliometric analysis provided the first and comprehensive summary within this field. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fingerprint analysis and quality consistency evaluation of flavonoid compounds for fermented Guava leaf by combining high-performance liquid chromatography time-of-flight electrospray ionization mass spectrometry and chemometric methods.

PubMed

Wang, Lu; Tian, Xiaofei; Wei, Wenhao; Chen, Gong; Wu, Zhenqiang

2016-10-01

Guava leaves are used in traditional herbal teas as antidiabetic therapies. Flavonoids are the main active of Guava leaves and have many physiological functions. However, the flavonoid compositions and activities of Guava leaves could change due to microbial fermentation. A high-performance liquid chromatography time-of-flight electrospray ionization mass spectrometry method was applied to identify the varieties of the flavonoids in Guava leaves before and after fermentation. High-performance liquid chromatography, hierarchical cluster analysis and principal component analysis were used to quantitatively determine the changes in flavonoid compositions and evaluate the consistency and quality of Guava leaves. Monascus anka Saccharomyces cerevisiae fermented Guava leaves contained 2.32- and 4.06-fold more total flavonoids and quercetin, respectively, than natural Guava leaves. The flavonoid compounds of the natural Guava leaves had similarities ranging from 0.837 to 0.927. The flavonoid compounds from the Monascus anka S. cerevisiae fermented Guava leaves had similarities higher than 0.993. This indicated that the quality consistency of the fermented Guava leaves was better than that of the natural Guava leaves. High-performance liquid chromatography fingerprinting and chemometric analysis are promising methods for evaluating the degree of fermentation of Guava leaves based on quality consistency, which could be used in assessing flavonoid compounds for the production of fermented Guava leaves. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Classification of the medicinal plants of the genus Atractylodes using high-performance liquid chromatography with diode array and tandem mass spectrometry detection combined with multivariate statistical analysis.

PubMed

Cho, Hyun-Deok; Kim, Unyong; Suh, Joon Hyuk; Eom, Han Young; Kim, Junghyun; Lee, Seul Gi; Choi, Yong Seok; Han, Sang Beom

2016-04-01

Analytical methods using high-performance liquid chromatography with diode array and tandem mass spectrometry detection were developed for the discrimination of the rhizomes of four Atractylodes medicinal plants: A. japonica, A. macrocephala, A. chinensis, and A. lancea. A quantitative study was performed, selecting five bioactive components, including atractylenolide I, II, III, eudesma-4(14),7(11)-dien-8-one and atractylodin, on twenty-six Atractylodes samples of various origins. Sample extraction was optimized to sonication with 80% methanol for 40 min at room temperature. High-performance liquid chromatography with diode array detection was established using a C18 column with a water/acetonitrile gradient system at a flow rate of 1.0 mL/min, and the detection wavelength was set at 236 nm. Liquid chromatography with tandem mass spectrometry was applied to certify the reliability of the quantitative results. The developed methods were validated by ensuring specificity, linearity, limit of quantification, accuracy, precision, recovery, robustness, and stability. Results showed that cangzhu contained higher amounts of atractylenolide I and atractylodin than baizhu, and especially atractylodin contents showed the greatest variation between baizhu and cangzhu. Multivariate statistical analysis, such as principal component analysis and hierarchical cluster analysis, were also employed for further classification of the Atractylodes plants. The established method was suitable for quality control of the Atractylodes plants. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Identification of Explosives from Porous Materials: Applications Using Reverse Phase High Performance Liquid Chromatography and Gas Chromatography

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

C.J. Miller; G. Elias; N.C. Schmitt

2010-06-01

High performance liquid chromatography and gas chromatography techniques are well documented and widely used for the detection of trace explosives from organic solvents. These techniques were modified to specifically identify and quantify explosives extracted from various materials taken from people who had recently handled explosives. Documented techniques were modified to specifically detect and quantify RDX, TNT, and PETN from denim, colored flannel, vinyl, and canvas extracted in methanol using no sample cleanup prior to analysis. The methanol extracts were injected directly into several different column types and analyzed by HPLC-UV and/or GC-ECD. This paper describes general screening methods that weremore » used to determine the presence of explosives in unknown samples and techniques that have been optimized for quantification of each explosive from the substrate extracts.« less

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.

A selective biomarker for confirming nitrofurazone residues in crab and shrimp using ultra-performance liquid chromatography-tandem mass spectrometry.

PubMed

Zhang, Shuai; Guo, Yuanming; Yan, Zhongyong; Sun, Xiumei; Zhang, Xiaojun

2015-12-01

Reliably detecting nitrofurazone (NFZ) residues in farmed crab and shrimp was previously hindered by lack of appropriately specific analytical methodology. Parent NFZ rapidly breaks down in meat, and the commonly used side-chain metabolite, semicarbazide (SEM), is non-specific as it occurs naturally in crustacean shell often leading to 'false positive' detections in meat. Using 5-nitro-2-furaldehyde (NF) as marker metabolite, following pre-column derivatization with 2,4-dinitrophenylhydrazine (DNPH), ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis in negative electrospray ionization mode enabled confirmation of NFZ residues in deliberately treated whole crab, crab meat and shrimp meat, with a limit of detection (LOD) and limit of quantification (LOQ) below 1 ng g(-1). Meanwhile, the derivatives of DNPH-NF were synthesized for the first time, purified by preparative liquid chromatography and structure characterized with nuclear magnetic resonance spectroscopy ((1)H-NMR). The purity of derivative was checked by ultra-performance liquid chromatography-tunable ultraviolet (UPLC-TUV), and the contents were beyond 99.9%. For comparison purposes, crustacean samples were analysed using both NF and SEM marker metabolites. NFZ treatment was revealed by both NF and SEM marker metabolites, but untreated crab also showed measurable levels of SEM which could potentially be misinterpreted as evidence of illegal NFZ use.

Determination of 2-alkylcyclobutanones by combining precolumn derivatization with 1-naphthalenyl hydrazine and ultra-performance liquid chromatography with fluorescence detection.

PubMed

Meng, Xiangpeng; Tong, Tong; Wang, Lianrong; Liu, Hanxia; Chan, Wan

2016-05-01

2-Alkylcyclobutanones (2-ACBs) are uniquely formed when triglycerides-containing food products are exposed to ionizing radiation. Thus, 2-ACBs have been used as marker molecules to identify irradiated food. Most methods to determine 2-ACBs involve mass spectrometric detection after chromatographic separation. The spectrofluorometer is rarely used to determine 2-ACBs because these molecules do not fluoresce. In this study, we developed an ultra-performance liquid chromatography (UPLC) method to determine 2-ACBs. 2-ACBs were converted into fluorophores after reacting with 1-naphthalenyl hydrazine to facilitate their sensitive and selective detection using a fluorescence detector (FLD). Analysis of 2-ACBs using our developed UPLC-FLD method allows sensitive determination of 2-ACBs at a detection limit of 2 ng 2-ACBs per g of fat (30 pg/injection), which is significantly lower than that of existing analytical methods. After validation for trueness and precision, the method was applied to γ-irradiated chicken samples to determine their 2-ACB content. Comparative studies employing liquid chromatography-tandem mass spectrometric method revealed no systematic difference between the two methods, thereby demonstrating that the proposed UPLC-FLD method can be suitably used to determine 2-ACBs in irradiated foodstuffs. Graphical Abstract Determination of radiation-induced food-borne 2-dodecylcyclobutanone and 2-tetradecylcyclobutanone by combining 1-naphthalenyl hydrazine derivatization and ultra-performance liquid chromatography with fluorescence detection.

Ergosterol from the soilborne fungus Ganoderma boninense.

PubMed

Toh Choon, R L; Sariah, M; Siti Mariam, M N

2012-10-01

Ergosterol is the main component of the fungal membrane and is not found in plants or other microbial cells. Therefore, it can be a useful biomarker for the quantification of fungal biomass. We are now reporting the first isolation and characterisation of ergosterol from the mycelium of G. boninense. The ergosterol structure was detected by Thin Liquid Chromatography (TLC) and Ultra Performance Liquid Chromatography (UPLC) and confirmed with Gas Chromatography coupled with Mass Spectrometry (GCMS) and Nuclear Magnetic Resonance (NMR) analysis. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrochemical Detectors in HPLC and Ion Chromatography.

PubMed

Horvai, George; Pungor, ErnÕ

1989-01-01

Back in 1952, the renowned Polish electrochemist Wiktor Kemula introduced chromato-polarography, 1 i.e., polaro-graphic detection for liquid chromatography. This technique continued to develop slowly until the early 1970s (for a review see Reference 2) when modem high-performance liquid chromatography (HPLC) emerged. This new, highly efficient chromatographc method could only be. used with detectors ensuring low dispersion. It was not easy to modify the dropping mercury electrode cells to satisfy this requirement. However, at the same time, electroanalytical chemists, who already had much experience in using carbon-based electrodes for oxidative detection in flow analysis, put forward the idea of oxidative amperometric detection in liquid chromatography. 3,4 In this technique, solid or quasi-solid (paste) electrodes were used and this made possible the construction of miniaturized cells with just a few microliter volume.

Investigation into the temporal stability of aqueous standard solutions of psilocin and psilocybin using high performance liquid chromatography.

PubMed

Anastos, N; Barnett, N W; Pfeffer, F M; Lewis, S W

2006-01-01

This paper reports an investigation into the temporal stability of aqueous solutions of psilocin and psilocybin reference drug standards over a period of fourteen days. This study was performed using high performance liquid chromatography utilising a (95:5% v/v) methanol: 10 mM ammonium formate, pH 3.5 mobile phase and absorption detection at 269 nm. It was found that the exclusion of light significantly prolonged the useful life of standards, with aqueous solutions of both psilocin and psilocybin being stable over a period of seven days.

Determination of Urine Albumin by New Simple High-Performance Liquid Chromatography Method.

PubMed

Klapkova, Eva; Fortova, Magdalena; Prusa, Richard; Moravcova, Libuse; Kotaska, Karel

2016-11-01

A simple high-performance liquid chromatography (HPLC) method was developed for the determination of albumin in patients' urine samples without coeluting proteins and was compared with the immunoturbidimetric determination of albumin. Urine albumin is important biomarker in diabetic patients, but part of it is immuno-nonreactive. Albumin was determined by high-performance liquid chromatography (HPLC), UV detection at 280 nm, Zorbax 300SB-C3 column. Immunoturbidimetric analysis was performed using commercial kit on automatic biochemistry analyzer COBAS INTEGRA ® 400, Roche Diagnostics GmbH, Manheim, Germany. The HLPC method was fully validated. No significant interference with other proteins (transferrin, α-1-acid glycoprotein, α-1-antichymotrypsin, antitrypsin, hemopexin) was found. The results from 301 urine samples were compared with immunochemical determination. We found a statistically significant difference between these methods (P = 0.0001, Mann-Whitney test). New simple HPLC method was developed for the determination of urine albumin without coeluting proteins. Our data indicate that the HPLC method is highly specific and more sensitive than immunoturbidimetry. © 2016 Wiley Periodicals, Inc.

Sensitivity enhancement by chromatographic peak concentration with ultra-high performance liquid chromatography-nuclear magnetic resonance spectroscopy for minor impurity analysis.

PubMed

Tokunaga, Takashi; Akagi, Ken-Ichi; Okamoto, Masahiko

2017-07-28

High performance liquid chromatography can be coupled with nuclear magnetic resonance (NMR) spectroscopy to give a powerful analytical method known as liquid chromatography-nuclear magnetic resonance (LC-NMR) spectroscopy, which can be used to determine the chemical structures of the components of complex mixtures. However, intrinsic limitations in the sensitivity of NMR spectroscopy have restricted the scope of this procedure, and resolving these limitations remains a critical problem for analysis. In this study, we coupled ultra-high performance liquid chromatography (UHPLC) with NMR to give a simple and versatile analytical method with higher sensitivity than conventional LC-NMR. UHPLC separation enabled the concentration of individual peaks to give a volume similar to that of the NMR flow cell, thereby maximizing the sensitivity to the theoretical upper limit. The UHPLC concentration of compound peaks present at typical impurity levels (5.0-13.1 nmol) in a mixture led to at most three-fold increase in the signal-to-noise ratio compared with LC-NMR. Furthermore, we demonstrated the use of UHPLC-NMR for obtaining structural information of a minor impurity in a reaction mixture in actual laboratory-scale development of a synthetic process. Using UHPLC-NMR, the experimental run times for chromatography and NMR were greatly reduced compared with LC-NMR. UHPLC-NMR successfully overcomes the difficulties associated with analyses of minor components in a complex mixture by LC-NMR, which are problematic even when an ultra-high field magnet and cryogenic probe are used. Copyright © 2017 Elsevier B.V. All rights reserved.

[Qualitative and quantitative analysis of amygdalin and its metabolite prunasin in plasma by ultra-high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry and ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry].

PubMed

Gao, Meng; Wang, Yuesheng; Wei, Huizhen; Ouyang, Hui; He, Mingzhen; Zeng, Lianqing; Shen, Fengyun; Guo, Qiang; Rao, Yi

2014-06-01

A method was developed for the determination of amygdalin and its metabolite prunasin in rat plasma after intragastric administration of Maxing shigan decoction. The analytes were identified by ultra-high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry and quantitatively determined by ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry. After purified by liquid-liquid extraction, the qualitative analysis of amygdalin and prunasin in the plasma sample was performed on a Shim-pack XR-ODS III HPLC column (75 mm x 2.0 mm, 1.6 microm), using acetonitrile-0.1% (v/v) formic acid aqueous solution. The detection was performed on a Triple TOF 5600 quadrupole time of flight mass spectrometer. The quantitative analysis of amygdalin and prunasin in the plasma sample was performed by separation on an Agilent C18 HPLC column (50 mm x 2.1 mm, 1.7 microm), using acetonitrile-0.1% (v/v) formic acid aqueous solution. The detection was performed on an AB Q-TRAP 4500 triple quadrupole mass spectrometer utilizing electrospray ionization (ESI) interface operated in negative ion mode and multiple-reaction monitoring (MRM) mode. The qualitative analysis results showed that amygdalin and its metabolite prunasin were detected in the plasma sample. The quantitative analysis results showed that the linear range of amygdalin was 1.05-4 200 ng/mL with the correlation coefficient of 0.999 0 and the linear range of prunasin was 1.25-2 490 ng/mL with the correlation coefficient of 0.997 0. The method had a good precision with the relative standard deviations (RSDs) lower than 9.20% and the overall recoveries varied from 82.33% to 95.25%. The limits of detection (LODs) of amygdalin and prunasin were 0.50 ng/mL. With good reproducibility, the method is simple, fast and effective for the qualitative and quantitative analysis of the amygdalin and prunasin in plasma sample of rats which were administered by Maxing shigan decoction.

[Separation and identification of 5 glycosidic flavor precursors in tobacco by ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry].

PubMed

Wu, Xinhua; Zhu, Ruizhi; Ren, Zhuoying; Wang, Kai; Mou, Dingrong; Wei, Wanzhi; Miao, Mingming

2009-11-01

A qualitative method for the identification of 5 main glycosidic flavor precursors in tobacco was developed by using ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI MS/MS) and gas chromatography-mass spectrometry (GC-MS). The glycosidic flavor precursors in tobacco were extracted with methanol, cleaned up with an XAD-2 column. The aglycones were later released by enzyme-mediated hydrolysis under the condition of pH 5. The 5 volatile aglycone moieties were identified by GC-MS standard spectra library. The precursor ions of glycosides were determined by using electrospray ionization mass spectrometry in negative ion mode, then the 5 glycosidic flavor precursors were identified by using product ion scan (MS2) finally, using UPLC-ESI MS/MS, separation and identification of 5 glycosidic flavor precursors were accomplished on an RP-C,8 column in the multiple reaction monitoring (MRM) mode by using methanol and acetic acid-ammonium acetate aqueous solution as eluent. This work lays a foundation for the analysis of glycosidic flavor precursors without the standards by using liquid chromatography-mass spectrometry.

Reversed-phase high-performance liquid chromatography of sulfur mustard in water

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

Raghuveeran, C.D.; Malhotra, R.C.; Dangi, R.S.

1993-01-01

A reversed-phase high-performance liquid chromatography method for the detection and quantitation of sulfur mustard (HD) in water is described with detection at 200 nm. The detection based on the solubility of HD in water revealed that extremely low quantities of HD (4 to 5 mg/L) only are soluble. Experience shows that water is still the medium of choice for the analysis of HD in water and aqueous effluents in spite of the minor handicap of its half-life of ca. 4 minutes, which only calls for speedy analysis.

Detection of Free Polyamines in Plants Subjected to Abiotic Stresses by High-Performance Liquid Chromatography (HPLC).

PubMed

Gong, Xiaoqing; Liu, Ji-Hong

2017-01-01

High-performance liquid chromatography (HPLC) is a sensitive, rapid, and accurate technique to detect and characterize various metabolites from plants. The metabolites are extracted with different solvents and eluted with appropriate mobile phases in a designed HPLC program. Polyamines are known to accumulate under abiotic stress conditions in various plant species and thought to provide protection against oxidative stress by scavenging reactive oxygen species. Here, we describe a common method to detect the free polyamines in plant tissues both qualitatively and quantitatively.

Optimizing separations in online comprehensive two‐dimensional liquid chromatography

PubMed Central

Gargano, Andrea F.G.; Schoenmakers, Peter J.

2017-01-01

Abstract Online comprehensive two‐dimensional liquid chromatography has become an attractive option for the analysis of complex nonvolatile samples found in various fields (e.g. environmental studies, food, life, and polymer sciences). Two‐dimensional liquid chromatography complements the highly popular hyphenated systems that combine liquid chromatography with mass spectrometry. Two‐dimensional liquid chromatography is also applied to the analysis of samples that are not compatible with mass spectrometry (e.g. high‐molecular‐weight polymers), providing important information on the distribution of the sample components along chemical dimensions (molecular weight, charge, lipophilicity, stereochemistry, etc.). Also, in comparison with conventional one‐dimensional liquid chromatography, two‐dimensional liquid chromatography provides a greater separation power (peak capacity). Because of the additional selectivity and higher peak capacity, the combination of two‐dimensional liquid chromatography with mass spectrometry allows for simpler mixtures of compounds to be introduced in the ion source at any given time, improving quantitative analysis by reducing matrix effects. In this review, we summarize the rationale and principles of two‐dimensional liquid chromatography experiments, describe advantages and disadvantages of combining different selectivities and discuss strategies to improve the quality of two‐dimensional liquid chromatography separations. PMID:29027363

Chromatographic instrumentation in space: past, present and future developments for exobiological studies

NASA Astrophysics Data System (ADS)

Raulin, F.; Sternberg, R.; Coscia, D.; Vidal-Madjar, C.; Millot, M.-C.; Sébille, B.; Israel, G.

1999-01-01

Several planetary exploration missions have already used chromatographic techniques to search for organic compounds, including complex organics, in extraterrestrial environments. So far, only gas chromatography (GC) has been used. In two cases (Viking and Cassini-Huygens), a Py-GC-MS instrument, coupling GC with a pyrolyzer and a mass spectrometer, has been flown. Powerful miniaturized Py-GC-MS instrumentation, with high resolution multi-GC columns and time-of-flight or Ion Trap mass spectrometers are under development, in the frame of the preparation of the Rosetta mission. There is now a strong need for new chromatographic instrumentation in space, in particular to perform detailed molecular analyses of complex non-volatile organics, including macromolecular compounds. Liquid Chromatography (LC), in particular High Performance Liquid Chromatography (HPLC) Supercritical Fluid Chromatography (SFC) or Chemical-Derivatization Gas Chromatography (CDGC) could provide a very efficient mean of analyzing a wide variety of exobiologically important compounds. LC or CDGC have never been used in space yet, but feasibility studies on their application in planetary mission are needed.

Development and validation of an ultra-performance convergence chromatography method for the quality control of Angelica gigas Nakai.

PubMed

Kim, Hyo Seon; Chun, Jin Mi; Kwon, Bo-In; Lee, A-Reum; Kim, Ho Kyoung; Lee, A Yeong

2016-10-01

Ultra-performance convergence chromatography, which integrates the advantages of supercritical fluid chromatography and ultra high performance liquid chromatography technologies, is an environmentally friendly analytical method that uses dramatically reduced amounts of organic solvents. An ultra-performance convergence chromatography method was developed and validated for the quantification of decursinol angelate and decursin in Angelica gigas using a CSH Fluoro-Phenyl column (2.1 mm × 150 mm, 1.7 μm) with a run time of 4 min. The method had an improved resolution and a shorter analysis time in comparison to the conventional high-performance liquid chromatography method. This method was validated in terms of linearity, precision, and accuracy. The limits of detection were 0.005 and 0.004 μg/mL for decursinol angelate and decursin, respectively, while the limits of quantitation were 0.014 and 0.012 μg/mL, respectively. The two components showed good regression (correlation coefficient (r 2 ) > 0.999), excellent precision (RSD < 2.28%), and acceptable recoveries (99.75-102.62%). The proposed method can be used to efficiently separate, characterize, and quantify decursinol angelate and decursin in Angelica gigas and its related medicinal materials or preparations, with the advantages of a shorter analysis time, greater sensitivity, and better environmental compatibility. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Modified extraction procedure for gas-liquid chromatography applied to the identification of anaerobic bacteria.

PubMed Central

Thomann, W R; Hill, G B

1986-01-01

Chloroform and ether commonly are used as solvents to extract metabolic organic acids for analysis by gas-liquid chromatography in the identification of anaerobic bacteria. Because these solvents are potentially hazardous to personnel, modified extraction procedures involving the use of a safer solvent, methyl tert-butyl ether were developed which remained both simple to perform and effective for organism identification. PMID:3700623

Determination of Total Arsenic and Speciation in Apple Juice by Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry: An Experiment for the Analytical Chemistry Laboratory

ERIC Educational Resources Information Center

He, Ping; Colon, Luis A.; Aga, Diana S.

2016-01-01

A two-part laboratory experiment was designed for upper-level analytical chemistry students to provide hands-on experience in the use of high performance liquid chromatography (HPLC) for separation and inductively coupled plasma mass spectrometry (ICP-MS) for detection. In the first part of the experiment, the students analyze total arsenic in…

Simultaneous analysis of different classes of phytohormones in coconut (Cocos nucifera L.) water using high-performance liquid chromatography and liquid chromatography-tandem mass spectrometry after solid-phase extraction.

PubMed

Ma, Zhen; Ge, Liya; Lee, Anna S Y; Yong, Jean Wan Hong; Tan, Swee Ngin; Ong, Eng Shi

2008-03-10

Coconut (Cocos nucifera L.) water, which contains many uncharacterized phytohormones is extensively used as a growth promoting supplement in plant tissue culture. In this paper, a high-performance liquid chromatography (HPLC) method was developed for the simultaneous determination of various classes phytohormones, including indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), abscisic acid (ABA), gibberellic acid (GA), zeatin (Z), N(6)-benzyladenine (BA), alpha-naphthaleneacetic acid (NAA) and 2,4-dichlorophenoxyacetic acid (2,4-D) in young coconut water (CW). The analysis was carried out using a reverse-phase HPLC gradient elution, with an aqueous mobile phase (containing 0.1% formic acid, pH adjusted to 3.2 with triethylamine (TEA)) modified by methanol, and solute detection made at 265 nm wavelength. The method was validated for specificity, quantification, accuracy and precision. After preconcentration of putative endogenous phytohormones in CW using C(18) solid-phase extraction (SPE) cartridges, the HPLC method was able to screen for putative endogenous phytohormones present in CW. Finally, the identities of the putative phytohormones present in CW were further confirmed using independent liquid chromatography-tandem mass spectrometry (LC-MS/MS) equipped with an electrospray ionization (ESI) interface.

Purification and identification of corn peptides that facilitate alcohol metabolism by semi-preparative high-performance liquid chromatography and nano liquid chromatography with electrospray ionization tandem mass spectrometry.

PubMed

Ma, Zhi-Li; Hou, Tao; Shi, Wen; Liu, Wei-Wei; Ibrahim, Salam A; He, Hui

2016-11-01

In this study, peptides that facilitate alcohol metabolism were purified and identified from corn protein hydrolysates. The ultra-filtered fraction with a molecular weight < 3 kDa (F3) potential activity was separated into six fractions (F3-H1-F3-H6) by semi-preparative high-performance liquid chromatography. Among the resultant six fractions, F3-H4 and F3-H5 exhibited the highest ability to eliminate alcohol in vivo. A total of 16 peptides with strong signal values were identified from F3-H4 and F3-H5 fractions by nano liquid chromatography coupled with electrospray ionization tandem mass spectrometry. Several identified peptides were then selected and synthesized to determine their potential to facilitate alcohol metabolism. We found that Leu-Leu and Pro-Phe were the key structure units in Gln-Leu-Leu-Pro-Phe responsible for this peptide's ability to facilitate alcohol metabolism. However, the role of Leu-Leu and Pro-Phe may be affected by peptide chain length and hydrophobic properties. Our results have thus provided some insight into the study of the structure-activity relationships of corn peptides. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Application of ionic liquids in liquid chromatography and electrodriven separation.

PubMed

Huang, Yi; Yao, Shun; Song, Hang

2013-08-01

Ionic liquids (ILs) are salts in the liquid state at ambient temperature, which are nonvolatile, nonflammable with high thermal stability and dissolve easily for a wide range of inorganic and organic materials. As a kind of potential green solvent, they show high efficiency and selectivity in the field of separation research, especially in instrumental analysis. Thus far, ILs have been successfully applied by many related researchers in high-performance liquid chromatography and capillary electrophoresis as chromatographic stationary phases, mobile phase additives or electroosmotic flow modifiers. This paper provides a detailed review of these applications in the study of natural products, foods, drugs and other fine chemicals. Furthermore, the prospects of ILs in liquid chromatographic and electrodriven techniques are discussed.

Adsorption of NH2 on Graphene in the Presence of Defects and Adsorbates

DTIC Science & Technology

2013-02-05

Carbobenzy- loxy Derivatives in High-Performance Liquid Chromatography and Supercritical Fluid Chromatography . J. Chromatogr., A 2005, 1100, 108−115. (7) Wang...being NH2. Amines are of interest because they are used in catalytic asymmetric synthesis,5 chromatography ,6 and as a biconjugate linker7 (i.e., between

Chemical analysis of Panax quinquefolius (North American ginseng): A review.

PubMed

Wang, Yaping; Choi, Hyung-Kyoon; Brinckmann, Josef A; Jiang, Xue; Huang, Linfang

2015-12-24

Panax quinquefolius (PQ) is one of the best-selling natural health products due to its proposed beneficial anti-aging, anti-cancer, anti-stress, anti-fatigue, and anxiolytic effects. In recent years, the quality of PQ has received considerable attention. Sensitive and accurate methods for qualitative and quantitative analyses of chemical constituents are necessary for the comprehensive quality control to ensure the safety and efficacy of PQ. This article reviews recent progress in the chemical analysis of PQ and its preparations. Numerous analytical techniques, including spectroscopy, thin-layer chromatography (TLC), gas chromatography (GC), high-performance liquid chromatography (HPLC), liquid chromatography/mass spectrometry (LC/MS), high-speed centrifugal partition chromatography (HSCPC), high-performance counter-current chromatography (HPCCC), nuclear magnetic resonance spectroscopy (NMR), and immunoassay, are described. Among these techniques, HPLC coupled with mass spectrometry (MS) is the most promising method for quality control. The challenges encountered in the chemical analysis of PQ are also briefly discussed, and the remaining questions regarding the quality control of PQ that require further investigation are highlighted. Copyright © 2015 Elsevier B.V. All rights reserved.

Ionic liquid-based air-assisted liquid-liquid microextraction followed by high performance liquid chromatography for the determination of five fungicides in juice samples.

PubMed

You, Xiangwei; Chen, Xiaochu; Liu, Fengmao; Hou, Fan; Li, Yiqiang

2018-01-15

A novel and simple ionic liquid-based air-assisted liquid-liquid microextraction technique combined with high performance liquid chromatography was developed to analyze five fungicides in juice samples. In this method, ionic liquid was used instead of a volatile organic solvent as the extraction solvent. The emulsion was formed by pulling in and pushing out the mixture of aqueous sample solution and extraction solvent repeatedly using a 10mL glass syringe. No organic dispersive solvent was required. Under the optimized conditions, the limits of detection (LODs) were 0.4-1.8μgL -1 at a signal-to-noise ratio of 3. The limits of quantification (LOQs) set as the lowest spiking levels with acceptable recovery in juices were 10μgL -1 , except for fludioxonil whose LOQ was 20μgL -1 . The proposed method was applied to determine the target fungicides in juice samples, and acceptable recoveries ranging from 74.9% to 115.4% were achieved. Copyright © 2017. Published by Elsevier Ltd.

Molecular differences between deuterated and protonated polystyrenes using reversed-phase high-performance liquid chromatography.

PubMed

Kayillo, Sindy; Gray, Michael J; Shalliker, R Andrew; Dennis, Gary R

2005-05-06

Isotopic substitution is a technique used to highlight particular bonds within a molecule for kinetic, spectroscopic and structure analysis. It is presumed that although some properties such as stretching frequencies will not be the same for substituted analogues, the chemical interactions will not vary appreciably as a function of labelling. Reversed-phase liquid chromatography has been used to demonstrate that there are significant differences between the chromatographic behaviour of a sequence of deuterated and protonated oligomeric polystyrenes. Two-dimensional reversed-phase liquid chromatography was used to show that even the diasteromers of the oligomers (n = 5) have retention mechanisms that are dependent on the subtle changes to the molecular conformation and electronic structure, which are a consequence of deuteration.

Characterization of the pigment fraction in sweet bell peppers (Capsicum annuum L.) harvested at green and overripe yellow and red stages by offline multidimensional convergence chromatography/liquid chromatography-mass spectrometry.

PubMed

Bonaccorsi, Ivana; Cacciola, Francesco; Utczas, Margita; Inferrera, Veronica; Giuffrida, Daniele; Donato, Paola; Dugo, Paola; Mondello, Luigi

2016-09-01

Offline multidimensional supercritical fluid chromatography combined with reversed-phase liquid chromatography was employed for the carotenoid and chlorophyll characterization in different sweet bell peppers (Capsicum annuum L.) for the first time. The first dimension consisted of an Acquity HSS C18 SB (100 × 3 mm id, 1.8 μm particles) column operated with a supercritical mobile phase in an ultra-performance convergence chromatography system, whereas the second dimension was performed in reversed-phase mode with a C30 (250 × 4.6 mm id, 3.0 μm particles) stationary phase combined with photodiode array and mass spectrometry detection. This approach allowed the determination of 115 different compounds belonging to chlorophylls, free xanthophylls, free carotenes, xanthophyll monoesters, and xanthophyll diesters, and proved to be a significant improvement in the pigments determination compared to the conventional one-dimensional liquid chromatography approach so far applied to the carotenoid analysis in the studied species. Moreover, the present study also aimed to investigate and to compare the carotenoid stability and composition in overripe yellow and red bell peppers collected directly from the plant, thus also evaluating whether biochemical changes are linked to carotenoid degradation in the nonclimacteric investigated fruits, for the first time. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Detailed analysis of petroleum hydrocarbon attenuation in biopiles by high-performance liquid chromatography followed by comprehensive two-dimensional gas chromatography.

PubMed

Mao, Debin; Lookman, Richard; Van De Weghe, Hendrik; Van Look, Dirk; Vanermen, Guido; De Brucker, Nicole; Diels, Ludo

2009-02-27

Enhanced bioremediation of petroleum hydrocarbons in two biopiles was quantified by high-performance liquid chromatography (HPLC) followed by comprehensive two-dimensional gas chromatography (GCXGC). The attenuation of 34 defined hydrocarbon classes was calculated by HPLC-GCXGC analysis of representative biopile samples at start-up and after 18 weeks of biopile operation. In general, a-cyclic alkanes were most efficiently removed from the biopiles, followed by monoaromatic hydrocarbons. Cycloalkanes and polycyclic aromatic hydrocarbons (PAHs) were more resistant to degradation. A-cyclic biomarkers farnesane, trimethyl-C13, norpristane, pristane and phytane dropped to only about 10% of their initial concentrations. On the other hand, C29-C31 hopane concentrations remained almost unaltered after 18 weeks of biopile operation, confirming their resistance to biodegradation. They are thus reliable indicators to estimate attenuation potential of petroleum hydrocarbons in biopile processed soils.

The offline combination of thin-layer chromatography and high-performance liquid chromatography with diode array detection and micrOTOF-Q mass spectrometry for the separation and identification of spinochromes from sea urchin (Strongylocentrotus droebachiensis) shells.

PubMed

Shikov, Alexander N; Ossipov, Vladimir I; Martiskainen, Olli; Pozharitskaya, Olga N; Ivanova, Svetlana A; Makarov, Valery G

2011-12-16

Thin-layer chromatography (TLC) with off-line high-performance liquid chromatography coupled to diode array detection and micrOTOF-Q mass spectrometry (HPLC-DAD-MS) resulted in the successful fractionation, separation and identification of spinochrome pigments from sea urchin (Strongylocentrotus droebachiensis) shells. Two fractions of pigments were separated by TLC and eluted with methanol using a TLC-MS interface. HPLC-DAD-MS analysis of the fractions indicated the presence of six sea urchin pigments: spinochrome monomers B and D, three spinochrome dimers (anhydroethylidene-6,6'-bis(2,3,7-trihydroxynaphthazarin) and its isomer and ethylidene-6,6'-bis(2,3,7-trihydroxynaphthazarin)), and one pigment that was preliminary identified as a spinochrome dimer with the structural formula C(22)H(16)O(16). Copyright © 2011 Elsevier B.V. All rights reserved.

Development of Impurity Profiling Methods Using Modern Analytical Techniques.

PubMed

Ramachandra, Bondigalla

2017-01-02

This review gives a brief introduction about the process- and product-related impurities and emphasizes on the development of novel analytical methods for their determination. It describes the application of modern analytical techniques, particularly the ultra-performance liquid chromatography (UPLC), liquid chromatography-mass spectrometry (LC-MS), high-resolution mass spectrometry (HRMS), gas chromatography-mass spectrometry (GC-MS) and high-performance thin layer chromatography (HPTLC). In addition to that, the application of nuclear magnetic resonance (NMR) spectroscopy was also discussed for the characterization of impurities and degradation products. The significance of the quality, efficacy and safety of drug substances/products, including the source of impurities, kinds of impurities, adverse effects by the presence of impurities, quality control of impurities, necessity for the development of impurity profiling methods, identification of impurities and regulatory aspects has been discussed. Other important aspects that have been discussed are forced degradation studies and the development of stability indicating assay methods.

Separation of three anthraquinone glycosides including two isomers by preparative high-performance liquid chromatography and high-speed countercurrent chromatography from Rheum tanguticum Maxim. ex Balf.

PubMed

Chen, Tao; Li, Hongmei; Zou, Denglang; Liu, Yongling; Chen, Chen; Zhou, Guoying; Li, Yulin

2016-08-01

Anthraquinone glycosides, such as chrysophanol 1-O-β-d-glucoside, chrysophanol 8-O-β-d-glucoside, and physion 8-O-β-d-glucoside, are the accepted important active components of Rheum tanguticum Maxim. ex Balf. due to their pharmacological properties: antifungal, antimicrobial, cytotoxic, and antioxidant activities. However, an effective method for the separation of the above-mentioned anthraquinone glycosides from this herb is not currently available. Especially, greater difficulty existed in the separation of the two isomers chrysophanol 1-O-β-d-glucoside and chrysophanol 8-O-β-d-glucoside. This study demonstrated an efficient strategy based on preparative high-performance liquid chromatography and high-speed countercurrent chromatography for the separation of the above-mentioned anthraquinone glycosides from Rheum tanguticum Maxim.ex Balf. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Screening and identification of radical scavengers from Neo-Taraxacum siphonanthum by online rapid screening method and nuclear magnetic resonance experiments.

PubMed

Shi, Shu Yun; Zhang, Yu Ping; Zhou, Hong Hao; Huang, Ke Long; Jiang, Xin Yu

2010-01-01

An online rapid screening method, the high-performance liquid chromatography (HPLC)-diode array detector (DAD)-radical scavenging detection (RSD)-electrospray ionization (ESI)-mass spectroscopy (MS)/MS system, was developed for the screening and identification of radical scavengers from Neo-Taraxacum siphonanthum, a new species found in China in 1989. For further characterization, the target compounds were isolated by silica column chromatography, preparative high-performance liquid chromatography (HPLC), HSCCC, and Sephadex LH-20 column chromatography and elucidated on the basis of ultraviolet (UV), ESI-MS/MS, and nuclear magnetic resonance (NMR) spectroscopy, as well as the chemical analysis. Eighteen antioxidative polyphenols (5 caffeic acid derivatives and 13 flavonoid derivatives) were characterized from Neo-T. siphonanthum. The distribution of all compounds was discussed in a chemosystematic context, which suggested that the genera Neo-Taraxacum and Taraxacum might relate chemosystematically.

Preparative isolation and purification of chemical constituents from the root of Adenophora tetraphlla by high-speed counter-current chromatography with evaporative light scattering detection.

PubMed

Yao, Shun; Liu, Renming; Huang, Xuefeng; Kong, Lingyi

2007-01-19

Preparative high-speed counter-current chromatography (HSCCC), as a continuous liquid-liquid partition chromatography with no solid support matrix, combined with evaporative light scattering detection (ELSD) was employed for systematic separation and purification of non-chromophoric chemical components from Chinese medicinal herb Adenophora tetraphlla (Thunb.), Fisch. Nine compounds, including alpha-spinasterol, beta-sitosterol, nonacosan-10-ol, 24-methylene cycloartanol, lupenone, 3-O-palmitoyl-beta-sitosterol, 3-O-beta-d-glucose-beta-sitosterol, eicosanoic acid and an unknown compound, were obtained. The compounds were all above 95% determined by high-performance liquid chromatography (HPLC)-ELSD, and their structures were identified by (1)H NMR and chemical ionization mass spectroscopy (CI-MS). The results demonstrate that HSCCC coupled with ELSD is a feasible and efficient technique for systematic isolation of non-chromophoric components from traditional medicinal herbs.

High-performance liquid chromatographic determination of ambroxol in human plasma.

PubMed

Nobilis, M; Pastera, J; Svoboda, D; Kvêtina, J; Macek, K

1992-10-23

Ambroxol has been determined in biological fluids using a rapid and sensitive high-performance liquid chromatographic method. The samples prepared from plasma by liquid-liquid extraction were analysed on reversed-phase silica gel by competing-ion chromatography with ultraviolet detection. The method was applied to the determination of ambroxol levels in twelve healthy volunteers after oral administration of 90 mg of ambroxol in tablets of Mucosolvan and Ambrosan.

Simultaneous determination of nitroimidazoles, benzimidazoles, and chloramphenicol components in bovine milk by ultra-high performance liquid chromatography-tandem mass spectrometry.

PubMed

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

2016-02-01

A sensitive, confirmatory ultra-high performance liquid chromatography-tandem mass spectrometric method was developed and validated to detect 23 veterinary drugs and metabolites (nitroimidazoles, benzimidazoles, and chloramphenicol components) in bovine milk. Compounds of interest were sequentially extracted from milk with acetonitrile and basified acetonitrile using sodium chloride to induce liquid-liquid partition. The extract was purified on a mixed mode solid-phase extraction cartridge. Using rapid polarity switching in electrospray ionization, a single injection was capable of detecting both positively and negatively charged analytes in a 9 min chromatography run time. Recoveries based on matrix-matched calibrations and isotope labeled internal standards for milk ranged from 51.7% to 101.8%. The detection limits and quantitation limits of the analytical method were found to be within the range of 2-20 ng/kg and 5-50 ng/kg, respectively. The recommended method is simple, specific, and reliable for the routine monitoring of nitroimidazoles, benzimidazoles, and chloramphenicol components in bovine milk samples. Copyright © 2015 Elsevier Ltd. All rights reserved.

Tunnel frit: a nonmetallic in-capillary frit for nanoflow ultra high-performance liquid chromatography-mass spectrometryapplications.

PubMed

Chen, Chao-Jung; Chen, Wei-Yun; Tseng, Mei-Chun; Chen, Yet-Ran

2012-01-03

In this study, an easy method to fabricate a durable in-capillary frit was developed for use in nanoflow liquid chromatography (nanoLC). A small orifice was tunneled into the sol-gel frit during the polymerization process resulting in the simple fabrication of a tunnel frit. A short packing tunnel frit column (2 cm, C(18) particles) was able to sustain over 10,000 psi continuous liquid flow for 10 days without observation of particle loss, and back pressure variation was less than 5%. The tunnel frit was successfully applied to the fabrication of nanoflow ultra high-performance liquid chromatography (nano-UHPLC) trap and analytical columns. In the analysis of tryptic peptides, the tunnel frit trap and analytical columns were demonstrated to have high separation efficiency and sensitivity. In analysis of phosphopeptides, the use of the nonmetallic tunnel frit column showed better sensitivity than the metallic frit column. This design can facilitate the preparation of nano-HPLC and nano-UHPLC columns and the packing material can easily be refilled when the column is severely contaminated or clogged. © 2011 American Chemical Society

Quality assessment of Herba Leonuri based on the analysis of multiple components using normal- and reversed-phase chromatographic methods.

PubMed

Dong, Shuya; He, Jiao; Hou, Huiping; Shuai, Yaping; Wang, Qi; Yang, Wenling; Sun, Zheng; Li, Qing; Bi, Kaishun; Liu, Ran

2017-12-01

A novel, improved, and comprehensive method for quality evaluation and discrimination of Herba Leonuri has been developed and validated based on normal- and reversed-phase chromatographic methods. To identify Herba Leonuri, normal- and reversed-phase high-performance thin-layer chromatography fingerprints were obtained by comparing the colors and R f values of the bands, and reversed-phase high-performance liquid chromatography fingerprints were obtained by using an Agilent Poroshell 120 SB-C18 within 28 min. By similarity analysis and hierarchical clustering analysis, we show that there are similar chromatographic patterns in Herba Leonuri samples, but significant differences in counterfeits and variants. To quantify the bio-active components of Herba Leonuri, reversed-phase high-performance liquid chromatography was performed to analyze syringate, leonurine, quercetin-3-O-robiniaglycoside, hyperoside, rutin, isoquercitrin, wogonin, and genkwanin simultaneously by single standard to determine multi-components method with rutin as internal standard. Meanwhile, normal-phase high-performance liquid chromatography was performed by using an Agilent ZORBAX HILIC Plus within 6 min to determine trigonelline and stachydrine using trigonelline as internal standard. Innovatively, among these compounds, bio-active components of quercetin-3-O-robiniaglycoside and trigonelline were first determined in Herba Leonuri. In general, the method integrating multi-chromatographic analyses offered an efficient way for the standardization and identification of Herba Leonuri. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Salting-out assisted liquid-liquid extraction coupled to ultra-high performance liquid chromatography-tandem mass spectrometry for the determination of tetracycline residues in infant foods.

PubMed

Moreno-González, David; García-Campaña, Ana M

2017-04-15

The use of salting-out assisted liquid-liquid extraction (SALLE) combined with ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) has been evaluated for the determination of tetracyclines in infant foods based on meat and vegetables or in milk. To obtain satisfactory extraction efficiencies for the studied analytes, several parameters affecting the SALLE procedure were optimized. Analytical performances of the method were satisfactory, obtaining limits of quantification lower than 0.48μgkg -1 in all cases. The precision, expressed as relative standard deviation (%, RSD) was below 11.3%. The extraction efficiency for fortified samples ranged from 89.2 to 96.8%, with RSDs lower than 7.3%. Matrix effect was evaluated for all samples studied, being lower than |21|% in all cases. In relation to the low solvent consumption, the proposed methodology could be considered rapid, cheap and environmentally friendly. Its applicability has been successfully tested in a wide range of infant foods. Copyright © 2016 Elsevier Ltd. All rights reserved.

Simultaneous Determination of Food-Related Biogenic Amines and Precursor Amino Acids Using in Situ Derivatization Ultrasound-Assisted Dispersive Liquid-Liquid Microextraction by Ultra-High-Performance Liquid Chromatography Tandem Mass Spectrometry.

PubMed

He, Yongrui; Zhao, Xian-En; Wang, Renjun; Wei, Na; Sun, Jing; Dang, Jun; Chen, Guang; Liu, Zhiqiang; Zhu, Shuyun; You, Jinmao

2016-11-02

A simple, rapid, sensitive, selective, and environmentally friendly method, based on in situ derivatization ultrasound-assisted dispersive liquid-liquid microextraction (in situ DUADLLME) coupled with ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) using multiple reaction monitoring (MRM) mode has been developed for the simultaneous determination of food-related biogenic amines and amino acids. A new mass-spectrometry-sensitive derivatization reagent 4'-carbonyl chloride rosamine (CCR) was designed, synthesized, and first reported. Parameters and conditions of in situ DUADLLME and UHPLC-MS/MS were optimized in detail. Under the optimized conditions, the in situ DUADLLME was completed speedily (within 1 min) with high derivatization efficiencies (≥98.5%). With the cleanup and concentration of microextraction step, good analytical performance was obtained for the analytes. The results showed that this method was accurate and practical for quantification of biogenic amines and amino acids in common food samples (red wine, beer, wine, cheese, sausage, and fish).

Analytical methodologies for broad metabolite coverage of exhaled breath condensate.

PubMed

Aksenov, Alexander A; Zamuruyev, Konstantin O; Pasamontes, Alberto; Brown, Joshua F; Schivo, Michael; Foutouhi, Soraya; Weimer, Bart C; Kenyon, Nicholas J; Davis, Cristina E

2017-09-01

Breath analysis has been gaining popularity as a non-invasive technique that is amenable to a broad range of medical uses. One of the persistent problems hampering the wide application of the breath analysis method is measurement variability of metabolite abundances stemming from differences in both sampling and analysis methodologies used in various studies. Mass spectrometry has been a method of choice for comprehensive metabolomic analysis. For the first time in the present study, we juxtapose the most commonly employed mass spectrometry-based analysis methodologies and directly compare the resultant coverages of detected compounds in exhaled breath condensate in order to guide methodology choices for exhaled breath condensate analysis studies. Four methods were explored to broaden the range of measured compounds across both the volatile and non-volatile domain. Liquid phase sampling with polyacrylate Solid-Phase MicroExtraction fiber, liquid phase extraction with a polydimethylsiloxane patch, and headspace sampling using Carboxen/Polydimethylsiloxane Solid-Phase MicroExtraction (SPME) followed by gas chromatography mass spectrometry were tested for the analysis of volatile fraction. Hydrophilic interaction liquid chromatography and reversed-phase chromatography high performance liquid chromatography mass spectrometry were used for analysis of non-volatile fraction. We found that liquid phase breath condensate extraction was notably superior compared to headspace extraction and differences in employed sorbents manifested altered metabolite coverages. The most pronounced effect was substantially enhanced metabolite capture for larger, higher-boiling compounds using polyacrylate SPME liquid phase sampling. The analysis of the non-volatile fraction of breath condensate by hydrophilic and reverse phase high performance liquid chromatography mass spectrometry indicated orthogonal metabolite coverage by these chromatography modes. We found that the metabolite coverage could be enhanced significantly with the use of organic solvent as a device rinse after breath sampling to collect the non-aqueous fraction as opposed to neat breath condensate sample. Here, we show the detected ranges of compounds in each case and provide a practical guide for methodology selection for optimal detection of specific compounds. Copyright © 2017 Elsevier B.V. All rights reserved.

Resolving Identification Issues of Saraca asoca from Its Adulterant and Commercial Samples Using Phytochemical Markers

PubMed Central

Hegde, Satisha; Hegde, Harsha Vasudev; Jalalpure, Sunil Satyappa; Peram, Malleswara Rao; Pai, Sandeep Ramachandra; Roy, Subarna

2017-01-01

Saraca asoca (Roxb.) De Wilde (Ashoka) is a highly valued endangered medicinal tree species from Western Ghats of India. Besides treating cardiac and circulatory problems, S. asoca provides immense relief in gynecological disorders. Higher price and demand, in contrast to the smaller population size of the plant, have motivated adulteration with other plants such as Polyalthia longifolia (Sonnerat) Thwaites. The fundamental concerns in quality control of S. asoca arise due to its part of medicinal value (Bark) and the chemical composition. Phytochemical fingerprinting with proper selection of analytical markers is a promising method in addressing quality control issues. In the present study, high-performance liquid chromatography of phenolic compounds (gallic acid, catechin, and epicatechin) coupled to multivariate analysis was used. Five samples each of S. asoca, P. longifolia from two localities alongside five commercial market samples showed evidence of adulteration. Subsequently, multivariate hierarchical cluster analysis and principal component analysis was established to discriminate the adulterants of S. asoca. The proposed method ascertains identification of S. asoca from its putative adulterant P. longifolia and commercial market samples. The data generated may also serve as baseline data to form a quality standard for pharmacopoeias. SUMMARY Simultaneous quantification of gallic acid, catechin, epicatechin from Saraca asoca by high-performance liquid chromatographyDetection of S. asoca from adulterant and commercial samplesUse of analytical method along with a statistical tool for addressing quality issues. Abbreviations used: HPLC: High Performance Liquid Chromatography; RP-HPLC: Reverse Phase High Performance Liquid Chromatography; CAT: Catechin; EPI: Epicatechin; GA: Gallic acid; PCA: Principal Component Analysis. PMID:28808391

Micellar liquid chromatography

NASA Astrophysics Data System (ADS)

Basova, Elena M.; Ivanov, Vadim M.; Shpigun, Oleg A.

1999-12-01

Background and possibilities of practical applications of micellar liquid chromatography (MLC) are considered. Various retention models in MLC, the effects of the nature and concentration of surfactants and organic modifiers, pH, temperature and ionic strength on the MLC efficiency and selectivity are discussed. The advantages and limitations of MLC are demonstrated. The performance of MLC is critically evaluated in relationship to the reversed-phase HPLC and ion-pair chromatography. The potential of application of MLC for the analysis of pharmaceuticals including that in biological fluids and separation of inorganic anions, transition metal cations, metal chelates and heteropoly compounds is described. The bibliography includes 146 references.

[Blood levels of homocysteine by high pressure liquid chromatography and comparison with two other techniques].

PubMed

Ceppa, F; Drouillard, I; Chianea, D; Burnat, P; Perrier, F; Vaillant, C; El Jahiri, Y

1999-01-01

Cardio-vascular diseases are the most common cause of death in industrialized countries. A new marker has emerged among offending risk factors in the past few years: homocysteine. This sulphured amino-acid is an important intermediate in transsulphuration and remethylation reactions of methionine's metabolism. We proposed to evaluate a home made method of determination for this parameter by high performance liquid chromatography (HPLC) and to compare it to fluorescence polarization immunoassay technique (FPIA) and to gaz phase chromatography (CG-SM). This method associated with good sensibility and precision remain much less expensive than FPIA technique.

Optimizing separations in online comprehensive two-dimensional liquid chromatography.

PubMed

Pirok, Bob W J; Gargano, Andrea F G; Schoenmakers, Peter J

2018-01-01

Online comprehensive two-dimensional liquid chromatography has become an attractive option for the analysis of complex nonvolatile samples found in various fields (e.g. environmental studies, food, life, and polymer sciences). Two-dimensional liquid chromatography complements the highly popular hyphenated systems that combine liquid chromatography with mass spectrometry. Two-dimensional liquid chromatography is also applied to the analysis of samples that are not compatible with mass spectrometry (e.g. high-molecular-weight polymers), providing important information on the distribution of the sample components along chemical dimensions (molecular weight, charge, lipophilicity, stereochemistry, etc.). Also, in comparison with conventional one-dimensional liquid chromatography, two-dimensional liquid chromatography provides a greater separation power (peak capacity). Because of the additional selectivity and higher peak capacity, the combination of two-dimensional liquid chromatography with mass spectrometry allows for simpler mixtures of compounds to be introduced in the ion source at any given time, improving quantitative analysis by reducing matrix effects. In this review, we summarize the rationale and principles of two-dimensional liquid chromatography experiments, describe advantages and disadvantages of combining different selectivities and discuss strategies to improve the quality of two-dimensional liquid chromatography separations. © 2017 The Authors. Journal of Separation Science published by WILEY-VCH Verlag GmbH & Co. KGaA.

Recent advances in micro-scale and nano-scale high-performance liquid-phase chromatography for proteome research.

PubMed

Tao, Dingyin; Zhang, Lihua; Shan, Yichu; Liang, Zhen; Zhang, Yukui

2011-01-01

High-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS-MS) is regarded as one of the most powerful techniques for separation and identification of proteins. Recently, much effort has been made to improve the separation capacity, detection sensitivity, and analysis throughput of micro- and nano-HPLC, by increasing column length, reducing column internal diameter, and using integrated techniques. Development of HPLC columns has also been rapid, as a result of the use of submicrometer packing materials and monolithic columns. All these innovations result in clearly improved performance of micro- and nano-HPLC for proteome research.

Quantification of sulphur amino acids by ultra-high performance liquid chromatography in aquatic invertebrates.

PubMed

Thera, Jennifer C; Kidd, Karen A; Dodge-Lynch, M Elaine; Bertolo, Robert F

2017-12-15

We examined the performance of an ultra-high performance liquid chromatography method to quantify protein-bound sulphur amino acids in zooplankton. Both cysteic acid and methionine sulfone were linear from 5 to 250 pmol (r 2  = 0.99), with a method detection limit of 13 pmol and 9 pmol, respectively. Although there was no matrix effect on linearity, adjacent peaks and co-eluting noise from the invertebrate proteins increased the detection limits when compared to common standards. Overall, performance characteristics were reproducible and accurate, and provide a means for quantifying sulphur amino acids in aquatic invertebrates, an understudied group. Copyright © 2017 Elsevier Inc. All rights reserved.

Approaches to High-Performance Preparative Chromatography of Proteins

NASA Astrophysics Data System (ADS)

Sun, Yan; Liu, Fu-Feng; Shi, Qing-Hong

Preparative liquid chromatography is widely used for the purification of chemical and biological substances. Different from high-performance liquid chromatography for the analysis of many different components at minimized sample loading, high-performance preparative chromatography is of much larger scale and should be of high resolution and high capacity at high operation speed and low to moderate pressure drop. There are various approaches to this end. For biochemical engineers, the traditional way is to model and optimize a purification process to make it exert its maximum capability. For high-performance separations, however, we need to improve chromatographic technology itself. We herein discuss four approaches in this review, mainly based on the recent studies in our group. The first is the development of high-performance matrices, because packing material is the central component of chromatography. Progress in the fabrication of superporous materials in both beaded and monolithic forms are reviewed. The second topic is the discovery and design of affinity ligands for proteins. In most chromatographic methods, proteins are separated based on their interactions with the ligands attached to the surface of porous media. A target-specific ligand can offer selective purification of desired proteins. Third, electrochromatography is discussed. An electric field applied to a chromatographic column can induce additional separation mechanisms besides chromatography, and result in electrokinetic transport of protein molecules and/or the fluid inside pores, thus leading to high-performance separations. Finally, expanded-bed adsorption is described for process integration to reduce separation steps and process time.

A general strategy for performing temperature-programming in high performance liquid chromatography--further improvements in the accuracy of retention time predictions of segmented temperature gradients.

PubMed

Wiese, Steffen; Teutenberg, Thorsten; Schmidt, Torsten C

2012-01-27

In the present work it is shown that the linear elution strength (LES) model which was adapted from temperature-programming gas chromatography (GC) can also be employed for systematic method development in high-temperature liquid chromatography (HT-HPLC). The ability to predict isothermal retention times based on temperature-gradient as well as isothermal input data was investigated. For a small temperature interval of ΔT=40°C, both approaches result in very similar predictions. Average relative errors of predicted retention times of 2.7% and 1.9% were observed for simulations based on isothermal and temperature-gradient measurements, respectively. Concurrently, it was investigated whether the accuracy of retention time predictions of segmented temperature gradients can be further improved by temperature dependent calculation of the parameter S(T) of the LES relationship. It was found that the accuracy of retention time predictions of multi-step temperature gradients can be improved to around 1.5%, if S(T) was also calculated temperature dependent. The adjusted experimental design making use of four temperature-gradient measurements was applied for systematic method development of selected food additives by high-temperature liquid chromatography. Method development was performed within a temperature interval from 40°C to 180°C using water as mobile phase. Two separation methods were established where selected food additives were baseline separated. In addition, a good agreement between simulation and experiment was observed, because an average relative error of predicted retention times of complex segmented temperature gradients less than 5% was observed. Finally, a schedule of recommendations to assist the practitioner during systematic method development in high-temperature liquid chromatography was established. Copyright © 2011 Elsevier B.V. All rights reserved.

Analysis of aldehydes in beer by gas-diffusion microextraction: characterization by high-performance liquid chromatography-diode-array detection-atmospheric pressure chemical ionization-mass spectrometry.

PubMed

Gonçalves, Luís Moreira; Magalhães, Paulo Jorge; Valente, Inês Maria; Pacheco, João Grosso; Dostálek, Pavel; Sýkora, David; Rodrigues, José António; Barros, Aquiles Araújo

2010-06-11

In this work, a recently developed extraction technique for sample preparation aiming the analysis of volatile and semi-volatile compounds named gas-diffusion microextraction (GDME) is applied in the chromatographic analysis of aldehydes in beer. Aldehydes-namely acetaldehyde (AA), methylpropanal (MA) and furfural (FA)-were simultaneously extracted and derivatized with 2,4-dinitrophenylhydrazine (DNPH), then the derivatives were separated and analyzed by high-performance liquid chromatography with spectrophotometric detection (HPLC-UV). The identity of the eluted compounds was confirmed by high-performance liquid chromatography-atmospheric pressure chemical ionization-mass-spectrometry detection in the negative ion mode (HPLC-APCI-MS). The developed methodology showed good repeatability (ca. 5%) and linearity as well as good limits of detection (AA-12.3, FA-1.5 and MA 5.4microgL(-1)) and quantification (AA-41, FA-4.9 and MA 18microgL(-1)); it also appears to be competitive in terms of speed and cost of analysis. Copyright 2010 Elsevier B.V. All rights reserved.

Isolation and purification of diastereoisomeric flavonolignans from silymarin by binary-column recycling preparative high-performance liquid chromatography.

PubMed

Zhao, Weiquan; Yang, Guang; Zhong, Fanyi; Yang, Nan; Zhao, Xin; Qi, Yunpeng; Fan, Guorong

2014-09-01

Silymarin extracted from Silybum marianum (L.) Gaertn consists of a large number of flavonolignans, of which diastereoisomeric flavonolignans including silybin A and silybin B, and isosilybin A and isosilybin B are the main bioactive components, whose preparation from the crude extracts is still a difficult task. In this work, binary-column recycling preparative high-performance liquid chromatography systems without sample loop trapping, where two columns were switched alternately via one or two six-port switching valves, were established and successfully applied to the isolation and purification of the four diastereoisomeric flavonolignans from silymarin. The proposed system showed significant advantages over conventional preparative high-performance liquid chromatography with a single column in increasing efficiency and reducing the cost. To obtain the same amounts of products, the proposed system spends only one tenth of the time that the conventional system spends, and needs only one eleventh of the solvent that the conventional system consumes. Using the proposed system, the four diastereoisomers were successfully isolated from silymarin with purities over 98%. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-performance liquid chromatography with fluorescence detection for the rapid analysis of pheophytins and pyropheophytins in virgin olive oil.

PubMed

Li, Xueqi; Woodman, Michael; Wang, Selina C

2015-08-01

Pheophytins and pyropheophytin are degradation products of chlorophyll pigments, and their ratios can be used as a sensitive indicator of stress during the manufacturing and storage of olive oil. They increase over time depending on the storage condition and if the oil is exposed to heat treatments during the refining process. The traditional analysis method includes solvent- and time-consuming steps of solid-phase extraction followed by analysis by high-performance liquid chromatography with ultraviolet detection. We developed an improved dilute/fluorescence method where multi-step sample preparation was replaced by a simple isopropanol dilution before the high-performance liquid chromatography injection. A quaternary solvent gradient method was used to include a fourth strong solvent wash on a quaternary gradient pump, which avoided the need to premix any solvents and greatly reduced the oil residues on the column from previous analysis. This new method not only reduces analysis cost and time but shows reliability, repeatability, and improved sensitivity, especially important for low-level samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization of polyoxyethylene tallow amine surfactants in technical mixtures and glyphosate formulations using ultra-high performance liquid chromatography and triple quadrupole mass spectrometry

USGS Publications Warehouse

Tush, Daniel; Loftin, Keith A.; Meyer, Michael T.

2013-01-01

Little is known about the occurrence, fate, and effects of the ancillary additives in pesticide formulations. Polyoxyethylene tallow amine (POEA) is a non-ionic surfactant used in many glyphosate formulations, a widely applied herbicide both in agricultural and urban environments. POEA has not been previously well characterized, but has been shown to be toxic to various aquatic organisms. Characterization of technical mixtures using ultra-high performance liquid chromatography (UHPLC) and mass spectrometry shows POEA is a complex combination of homologs of different aliphatic moieties and ranges of ethoxylate units. Tandem mass spectrometry experiments indicate that POEA homologs generate no product ions readily suitable for quantitative analysis due to poor sensitivity. A comparison of multiple high performance liquid chromatography (HPLC) and UHPLC analytical columns indicates that the stationary phase is more important in column selection than other parameters for the separation of POEA. Analysis of several agricultural and household glyphosate formulations confirms that POEA is a common ingredient but ethoxylate distributions among formulations vary.

Analysis of microdialysate monoamines, including noradrenaline, dopamine and serotonin, using capillary ultra-high performance liquid chromatography and electrochemical detection.

PubMed

Ferry, Barbara; Gifu, Elena-Patricia; Sandu, Ioana; Denoroy, Luc; Parrot, Sandrine

2014-03-01

Electrochemical methods are very often used to detect catecholamine and indolamine neurotransmitters separated by conventional reverse-phase high performance liquid chromatography (HPLC). The present paper presents the development of a chromatographic method to detect monoamines present in low-volume brain dialysis samples using a capillary column filled with sub-2μm particles. Several parameters (repeatability, linearity, accuracy, limit of detection) for this new ultrahigh performance liquid chromatography (UHPLC) method with electrochemical detection were examined after optimization of the analytical conditions. Noradrenaline, adrenaline, serotonin, dopamine and its metabolite 3-methoxytyramine were separated in 1μL of injected sample volume; they were detected above concentrations of 0.5-1nmol/L, with 2.1-9.5% accuracy and intra-assay repeatability equal to or less than 6%. The final method was applied to very low volume dialysates from rat brain containing monoamine traces. The study demonstrates that capillary UHPLC with electrochemical detection is suitable for monitoring dialysate monoamines collected at high sampling rate. Copyright © 2014 Elsevier B.V. All rights reserved.

Core-shell microspheres with porous nanostructured shells for liquid chromatography.

PubMed

Ahmed, Adham; Skinley, Kevin; Herodotou, Stephanie; Zhang, Haifei

2018-01-01

The development of new stationary phases has been the key aspect for fast and efficient high-performance liquid chromatography separation with relatively low backpressure. Core-shell particles, with a solid core and porous shell, have been extensively investigated and commercially manufactured in the last decade. The excellent performance of core-shell particles columns has been recorded for a wide range of analytes, covering small and large molecules, neutral and ionic (acidic and basic), biomolecules and metabolites. In this review, we first introduce the advance and advantages of core-shell particles (or more widely known as superficially porous particles) against non-porous particles and fully porous particles. This is followed by the detailed description of various methods used to fabricate core-shell particles. We then discuss the applications of common silica core-shell particles (mostly commercially manufactured), spheres-on-sphere particles and core-shell particles with a non-silica shell. This review concludes with a summary and perspective on the development of stationary phase materials for high-performance liquid chromatography applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Flavonoid content and antioxidant capacity of spinach genotypes determined by high-performance liquid chromatography/mass spectrometry

USDA-ARS?s Scientific Manuscript database

Flavonoids in different spinach genotypes were separated, identified, and quantified by a high-performance liquid chromatographic method with photodiode array and mass spectrometric detection. The antioxidant capacities of the genotypes were also measured using two antioxidant assays - oxygen radica...

SEPARATION AND QUANTITATION OF NITROBENZENES AND THEIR REDUCTION PRODUCTS NITROANILINES AND PHENYLENEDIAMINES BY REVERSED=PHASE HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY

EPA Science Inventory

A reversed-phase high-performance liquid chromatographic method for the separation and quantitation of a mixture consisting of nitrobenzene, dinitrobenzene isomers, 1,3,5-trinitrobenzene and their reduction products: aniline, nitroanilines and phenylenediamines has been developed...

FIXED DOSE COMBINATIONS WITH SELECTIVE BETA-BLOCKERS: QUANTITATIVE DETERMINATION IN BIOLOGICAL FLUIDS.

PubMed

Mahu, Ştefania Corina; Hăncianu, Monica; Agoroaei, Luminiţa; Grigoriu, Ioana Cezara; Strugaru, Anca Monica; Butnaru, Elena

2015-01-01

Hypertension is one of the most common causes of death, a complex and incompletely controlled disease for millions of patients. Metoprolol, bisoprolol, nebivolol and atenolol are selective beta-blockers frequently used in the management of arterial hypertension, alone or in fixed combination with other substances. This study presents the most used analytical methods for simultaneous determination in biological fluids of fixed combinations containing selective beta-blockers. Articles in Pub-Med, Science Direct and Wiley Journals databases published between years 2004-2014 were reviewed. Methods such as liquid chromatography--mass spectrometry--mass spectrometry (LC-MS/MS), high performance liquid chromatography (HPLC) or high performance liquid chromatography--mass spectrometry (HPLC-MS) were used for determination of fixed combination with beta-blockers in human plasma, rat plasma and human breast milk. LC-MS/MS method was used for simultaneous determination of fixed combinations of metoprolol with simvastatin, hydrochlorothiazide or ramipril, combinations of nebivolol and valsartan, or atenolol and amlodipine. Biological samples were processed by protein precipitation techniques or by liquid-liquid extraction. For the determination of fixed dose combinations of felodipine and metoprolol in rat plasma liquid chromatography--electrospray ionization--mass spectrometry (LC-ESI-MS/MS) was applied, using phenacetin as internal standard. HPLC-MS method was applied for the determination of bisoprolol and hydrochlorothiazide in human plasma. For the determination of atenolol and chlorthalidone from human breast milk and human plasma the HPLC method was used. The analytical methods were validated according to the specialized guidelines, and were applied to biological samples, thing that confirms the permanent concern of researchers in this field.

A green deep eutectic solvent dispersive liquid-liquid micro-extraction (DES-DLLME) for the UHPLC-PDA determination of oxyprenylated phenylpropanoids in olive, soy, peanuts, corn, and sunflower oil.

PubMed

Ferrone, Vincenzo; Genovese, Salvatore; Carlucci, Maura; Tiecco, Matteo; Germani, Raimondo; Preziuso, Francesca; Epifano, Francesco; Carlucci, Giuseppe; Taddeo, Vito Alessandro

2018-04-15

A green dispersive liquid-liquid microextraction (DLLME) using deep eutectic solvent (DES) as the extracting solvent has been developed and applied for the simultaneous quantification of ferulic acid, umbelliferone, boropinic acid, 7-isopentenyloxycoumarin, 4'-geranyloxyferulic acid (GOFA), and auraptene in some vegetable oils using ultra high performance liquid chromatography (UHPLC) with photodiode array detection (PDA). All parameters in the extraction step, including selection and loading of both extracting and dispersing solvents, amount of both extractant and disperser solvent were investigated and optimized. PhAA/TMG DES achieved higher recovery and enrichment factor compared to other DESs. The validated method showed good linearity with correlation coefficients, r 2 >0.9990 for all the analytes. Furthermore, this is the first time that eco-friendly solvents are used for the extraction of oxyprenylated phenylpropanoids and the corresponding extract analyzed with ultra high performance liquid chromatography with photodiode array detection. Copyright © 2017 Elsevier Ltd. All rights reserved.

A simple and sensitive determination of histamine and N tau-methylhistamine in biological fluids by high-performance liquid chromatography with electrochemical detection.

PubMed

Houdi, A A; Crooks, P A; Van Loon, G R; Schubert, C A

1987-05-01

The determination of picomolar levels of histamine and its major metabolite, N tau-methylhistamine, in biological fluids was achieved using reversed-phase liquid chromatography coupled with electrochemical detection. A simple sample purification procedure for blood and urine samples was carried out prior to analysis using an Amberlite CG-50 cation-exchange resin, which afforded an excellent recovery of both compounds.

High-performance Liquid Chromatographic Ultraviolet Detection of Nilotinib in Human Plasma from Patients with Chronic Myelogenous Leukemia, and Comparison with Liquid Chromatography-Tandem Mass Spectrometry.

PubMed

Nakahara, Ryosuke; Satho, Yuhki; Itoh, Hiroki

2016-11-01

A method for determining nilotinib concentration in human plasma is proposed using high-performance liquid chromatography and ultraviolet detection. Nilotinib and the internal standard dasatinib were separated using a mobile phase of 0.5% Na 2 PO 4 H 2 O (pH 2.5)-acetonitrile-methanol (55:25:20, v/v/v) on a Capcell Pak C18 MG II column (250 × 4.6 mm) at a flow rate of 1.0 ml/min, and ultraviolet measurement at 250 nm. The calibration curve exhibited linearity over the nilotinib concentration range of 50-2,500 ng/ml at 250 nm, with relative standard deviations (n = 5) of 7.1%, 2.5%, and 2.9% for 250, 1,500, and 2,500 ng/ml, respectively. The detection limit for nilotinib was 5 ng/ml due to three blank determinations (ρ = 3). This method was successfully applied to assaying nilotinib in human plasma samples from patients with chronic myelogenous leukemia. In addition, we compared the results with those measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) at BML, Inc. (a commercial laboratory). A strong correlation was observed between the nilotinib concentrations measured by our high-performance liquid chromatographic method and those obtained by LC/MS-MS (r 2 = 0.988, P < 0.01). © 2016 Wiley Periodicals, Inc.

Application of dispersive liquid-liquid microextraction for the preconcentration of eight parabens in real samples and their determination by high-performance liquid chromatography.

PubMed

Shen, Xiong; Liang, Jian; Zheng, Luxia; Lv, Qianzhou; Wang, Hong

2017-11-01

A simple and sensitive method for the simultaneous determination of eight parabens in human plasma and urine samples was developed. The samples were preconcentrated using dispersive liquid-liquid microextraction based on the solidification of floating organic drops and determined by high-performance liquid chromatography with ultraviolet detection. The influence of variables affecting the extraction efficiency was investigated and optimized using Placket-Burman design and Box-Behnken design. The optimized values were: 58 μL of 1-decanol (as extraction solvent), 0.65 mL methanol (as disperser solvent), 1.5% w/v NaCl in 5.0 mL of sample solution, pH 10.6, and 4.0 min centrifugation at 4000 rpm. The extract was injected into the high-performance liquid chromatography system for analysis. Under the optimum conditions, the linear ranges for eight parabens in plasma and urine were 1.0-1000 ng/mL, with correlation coefficients above 0.994. The limit of detection was 0.2-0.4 and 0.1-0.4 ng/mL for plasma and urine samples, respectively. Relative recoveries were between 80.3 and 110.7%, while relative standard deviations were less than 5.4%. Finally, the method was applied to analyze the parabens in 98 patients of primary breast cancer. Results showed that parabens existed widely, at least one paraben detected in 96.9% (95/98) of plasma samples and 98.0% (96/98) of urine samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A strategy for screening of α-glucosidase inhibitors from Morus alba root bark based on the ligand fishing combined with high-performance liquid chromatography mass spectrometer and molecular docking.

PubMed

Wang, Zhen; Li, Xiaoqing; Chen, Menghan; Liu, Feiyan; Han, Chao; Kong, Lingyi; Luo, Jianguang

2018-04-01

A new method based on ligand fishing combined with high-performance liquid chromatography quadrupole-time-of-flight mass spectrometer and molecular docking was established to screen α-glucosidase inhibitors from a traditional Chinese medicine Morus alba root bark. α-Glucosidase was immobilized on magnetic nanoparticles, used as a solid support to incubate with crude extract. After ligand fishing, the eluates were analyzed by high-performance liquid chromatography quadrupole-time-of-flight mass spectrometer, obtaining eleven ligands (1-4, 6-12) eventually. In order to discriminate the non-specific binders and discover powerful enzyme inhibitors, molecular docking was further performed and three of the eleven ligands were optimized to be excellent α-glucosidase inhibitors by the confirmation of isolation and bioassay of individual compounds. These three ligands, sanggenons G (6), O (7) and sanggenol G (12) exhibited striking inhibitory activities with extremely low IC 50 values. The results suggest that established method will be applied to a wide range of target protein to screen potential bioactive constituents from herbal medicines. Copyright © 2017 Elsevier B.V. All rights reserved.

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

PubMed

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

2016-06-01

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

Sequence, taste and umami-enhancing effect of the peptides separated from soy sauce.

PubMed

Zhuang, Mingzhu; Lin, Lianzhu; Zhao, Mouming; Dong, Yi; Sun-Waterhouse, Dongxiao; Chen, Huiping; Qiu, Chaoying; Su, Guowan

2016-09-01

Five tasty peptides were separated from soy sauce, by sensory-guided fractionation, using macroporous resin, medium-pressure liquid chromatography and reverse phase-high performance liquid chromatography, and identified by ultra-performance liquid chromatography tandem mass-spectrometry as ALPEEV, LPEEV, AQALQAQA, EQQQQ and EAGIQ (which originated from glycinin A1bB2-445, glycinin A1bB2-445, cobyric acid synthase, leucine-tRNA ligase and glycoprotein glucosyltransferase, respectively). LPEEV, AQALQAQA and EQQQQ tasted umami with threshold values of 0.43, 1.25 and 0.76mmol/l, respectively. ALPEEV and EAGIQ had minimal umami taste, but ALPEEV, EAGIQ and LPEEV showed umami-enhancement with a threshold estimated at 1.52, 1.94 and 3.41mmol/l, respectively. In addition, the synthetic peptides showed much better sensory taste than mixtures of their constitutive amino acids. It indicated that peptides might play an important role in the umami taste of soy sauce. Copyright © 2016 Elsevier Ltd. All rights reserved.

Neutral monosaccharide composition analysis of plant-derived oligo- and polysaccharides by high performance liquid chromatography.

PubMed

Yan, Jun; Shi, Songshan; Wang, Hongwei; Liu, Ruimin; Li, Ning; Chen, Yonglin; Wang, Shunchun

2016-01-20

A novel analytical method for neutral monosaccharide composition analysis of plant-derived oligo- and polysaccharides was developed using hydrophilic interaction liquid chromatography coupled to a charged aerosol detector. The effects of column type, additives, pH and column temperature on retention and separation were evaluated. Additionally, the method could distinguish potential impurities in samples, including chloride, sulfate and sodium, from sugars. The results of validation demonstrated that this method had good linearity (R(2) ≥ 0.9981), high precision (relative standard deviation ≤ 4.43%), and adequate accuracy (94.02-103.37% recovery) and sensitivity (detection limit: 15-40 ng). Finally, the monosaccharide compositions of the polysaccharide from Eclipta prostrasta L. and stachyose were successfully profiled through this method. This report represents the first time that all of these common monosaccharides could be well-separated and determined simultaneously by high performance liquid chromatography without additional derivatization. This newly developed method is convenient, efficient and reliable for monosaccharide analysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

PubMed

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

2015-09-30

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

Preparative isolation of flavonoid glycosides from Sphaerophysa salsula using hydrophilic interaction solid-phase extraction coupled with two-dimensional preparative liquid chromatography.

PubMed

Jiao, Lijin; Tao, Yanduo; Wang, Weidong; Shao, Yun; Mei, Lijuan; Wang, Qilan; Dang, Jun

2017-10-01

An offline preparative two-dimensional reversed-phase liquid chromatography/hydrophilic interaction liquid chromatography coupled with hydrophilic interaction solid-phase extraction method was developed for the preparative isolation of flavonoid glycosides from a crude sample of Sphaerophysa salsula. First, the non-flavonoids were removed using an XAmide solid-phase extraction cartridge. Based on the separation results of three different chromatographic stationary phases, the first-dimensional preparation was performed on an XAqua C18 prep column, and 15 fractions were obtained from the 5.2 g target sample. Then, three representative fractions were selected for additional purification on an XAmide preparative column to further isolate the flavonoid glycosides. In all, eight flavonoid glycosides were isolated in purities over 97%. The results demonstrated that the two-dimensional liquid chromatography method used in this study was effective for the preparative separation of flavonoid glycosides from Sphaerophysa salsula. Additionally, this method showed great potential for the separation of flavonoid glycosides from other plant materials. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Characterization of the efficiency of microbore liquid chromatography columns by van Deemter and kinetic plot analysis.

PubMed

Hetzel, Terence; Loeker, Denise; Teutenberg, Thorsten; Schmidt, Torsten C

2016-10-01

The efficiency of miniaturized liquid chromatography columns with inner diameters between 200 and 300 μm has been investigated using a dedicated micro-liquid chromatography system. Fully porous, core-shell and monolithic commercially available stationary phases were compared applying van Deemter and kinetic plot analysis. The sub-2 μm fully porous as well as the 2.7 μm core-shell particle packed columns showed superior efficiency and similar values for the minimum reduced plate heights (2.56-2.69) before correction for extra-column contribution compared to normal-bore columns. Moreover, the influence of extra-column contribution was investigated to demonstrate the difference between apparent and intrinsic efficiency by replacing the column by a zero dead volume union to determine the band spreading caused by the system. It was demonstrated that 72% of the intrinsic efficiency could be reached. The results of the kinetic plot analysis indicate the superior performance of the sub-2 μm fully porous particle packed column for ultra-fast liquid chromatography. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of Grayanotoxins from Rhododendron brachycarpum in Dietary Supplements and Homemade Wine by Liquid Chromatography-Quadrupole Time-of-Flight-Mass Spectrometry and Liquid Chromatography-Tandem Mass Spectrometry.

PubMed

Hwang, Taeik; Noh, Eunyoung; Jeong, Ji Hye; Park, Sung-Kwan; Shin, Dongwoo; Kang, Hoil

2018-02-28

A sensitive and specific high-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry (LC-QTOF-MS) method combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for the determination of grayanotoxins I and III in dietary supplements and homemade wine. Grayanotoxins I and III were successfully extracted using solid-phase extraction cartridges, characterized by LC-QTOF-MS, and quantitated by LC-MS/MS. The LC-MS/MS calibration curves were linear over concentrations of 10-100 ng/mL (grayanotoxin I) and 20-400 ng/mL (grayanotoxin III). Grayanotoxins I and III were found in 51 foodstuffs, with quantitative determinations revealing total toxin concentrations of 18.4-101 000 ng/mL (grayanotoxin I) and 15.3-56 000 ng/mL (grayanotoxin III). The potential of the validated method was demonstrated by successful quantitative analysis of grayanotoxins I and III in dietary supplements and homemade wine; the method appears suitable for the routine detection of grayanotoxins I and III from Rhododendron brachycarpum.

Preparative isolation and characterization of some minor impurities of astaxanthin by high-performance liquid chromatography.

PubMed

Rao, R Nageswara; Alvi, S Naseeruddin; Rao, B Nageswara

2005-05-27

A simple and rapid preparative high-performance liquid chromatography (HPLC) method has been developed to isolate and characterize some minor impurities of astaxanthin using a normal-phase Lichrosorb silica column with n-hexane-acetone-tetrahydrofuran (90:2:8, v/v/v) as mobile-phase and detection at 475 nm. The isolated impurities were characterized as astacene, dehydro astacene and apoastaxanthinal by UV-vis, ESI-MS, 1H and 13C NMR spectroscopy and the molecular structures were assigned. The impurities collected using the developed conditions were over 98% pure.

ICSH recommendations for assessing automated high-performance liquid chromatography and capillary electrophoresis equipment for the quantitation of HbA2.

PubMed

Stephens, A D; Colah, R; Fucharoen, S; Hoyer, J; Keren, D; McFarlane, A; Perrett, D; Wild, B J

2015-10-01

Automated high performance liquid chromatography and Capillary electrophoresis are used to quantitate the proportion of Hemoglobin A2 (HbA2 ) in blood samples order to enable screening and diagnosis of carriers of β-thalassemia. Since there is only a very small difference in HbA2 levels between people who are carriers and people who are not carriers such analyses need to be both precise and accurate. This paper examines the different parameters of such equipment and discusses how they should be assessed. © 2015 John Wiley & Sons Ltd.

Ethanolic extraction, purification, and partial characterization of a fluorescent toxin from the coral reef crab, Lophozozymus pictor.

PubMed

Lau, C O; Tan, C H; Khoo, H E; Li, Q T; Yuen, R

1995-01-01

A purification procedure for Lophozozymus pictor toxin (LPTX) following ethanolic extraction of whole crab homogenate is described. The ethanol-extracted toxin (LPTX-E) had higher yield and specific activity than the hot aqueous-extracted one (LPTX-H). It was found that LPTX-E was fluorescent and cochromatographed with LPTX-H on two-dimensional thin-layer chromatography. Although LPTX-E, LPTX-H, and palytoxin (P. caribaeorum, PTX) had similar migration and retention times when analysed on high performance capillary electrophoresis and gel permeation-high performance liquid chromatography respectively, LPTX-E and LPTX-H were both fluorescent in contrast to PTX. In addition, LPTX-E had a different retention time compared with PTX when chromatographed on reversed phase high performance liquid chromatography in the solvent system 80% acetonitrile and 0.02 M Tris-HCl, pH 7.2, at a 4:1 ratio, respectively, indicating some differences in their chemical structures.

Use of absorbent materials in on-line coupled reversed-phase liquid chromatography-gas chromatography via the through oven transfer adsorption desorption interface.

PubMed

Flores, Gema; Díaz-Plaza, Eva María; Cortés, Jose Manuel; Villén, Jesús; Herraiz, Marta

2008-11-21

The use of absorbents as retaining materials in the through oven transfer adsorption desorption interface (TOTAD) of an on-line coupled reversed-phase liquid chromatography-gas chromatography system (RPLC-GC) is proposed for the first time. A comparative study of an adsorbent (Tenax TA) and two absorbents, namely polydimethylsiloxane and poly(50% phenyl/50% methylsiloxane) is performed to establish the best experimental conditions for the automated and simultaneous determination of 15 organophosphorus and organochlorine pesticide residues in olive oil. The proposed method provides satisfactory repeatability (RSDs lower, in general, than 8.5%) and sensitivity (limits of detection ranging from 0.6 to 81.9 microg/L) for the investigated compounds.

Fast liquid chromatography combined with mass spectrometry for the analysis of metabolites and proteins in human body fluids.

PubMed

Kortz, Linda; Helmschrodt, Christin; Ceglarek, Uta

2011-03-01

In the last decade various analytical strategies have been established to enhance separation speed and efficiency in high performance liquid chromatography applications. Chromatographic supports based on monolithic material, small porous particles, and porous layer beads have been developed and commercialized to improve throughput and separation efficiency. This paper provides an overview of current developments in fast chromatography combined with mass spectrometry for the analysis of metabolites and proteins in clinical applications. Advances and limitations of fast chromatography for the combination with mass spectrometry are discussed. Practical aspects of, recent developments in, and the present status of high-throughput analysis of human body fluids for therapeutic drug monitoring, toxicology, clinical metabolomics, and proteomics are presented.

Fully automated multifunctional ultrahigh pressure liquid chromatography system for advanced proteome analyses

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

Lee, Jung Hwa; Hyung, Seok-Won; Mun, Dong-Gi

2012-08-03

A multi-functional liquid chromatography system that performs 1-dimensional, 2-dimensional (strong cation exchange/reverse phase liquid chromatography, or SCX/RPLC) separations, and online phosphopeptides enrichment using a single binary nano-flow pump has been developed. With a simple operation of a function selection valve, which is equipped with a SCX column and a TiO2 (titanium dioxide) column, a fully automated selection of three different experiment modes was achieved. Because the current system uses essentially the same solvent flow paths, the same trap column, and the same separation column for reverse-phase separation of 1D, 2D, and online phosphopeptides enrichment experiments, the elution time information obtainedmore » from these experiments is in excellent agreement, which facilitates correlating peptide information from different experiments.« less

Acrylamide: formation, occurrence in food products, detection methods, and legislation.

PubMed

Arvanitoyannis, Ioannis S; Dionisopoulou, Niki

2014-01-01

This review aims at summarizing the most recent updates in the field of acrylamide (AA) formation (mechanism, conditions) and the determination of AA in a number of foods (fried or baked potatoes, chips, coffee, bread, etc). The methods applied for AA detection [Capillary Electrophoresis-Mass Spectrometry (CE-MS), Liquid Chromatography-Mass Spectrometry (LC-MS), Non-Aqueous Capillary Electrophoresis (NACE), High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS), Pressurized Fluid Extraction (PFE), Matrix Solid-Phase Dispersion (MSPD), Gas Chromatography-Mass Spectrometry (GC-MS), Solid-Phase MicroExtraction-Gas Chromatography (SPME-GC), Enzyme Linked Immunosorbent Assay (ELISA), and MicroEmulsion ElectroKinetic Chromatography (MEEKC) are presented and commented. Several informative figures and tables are included to show the effect of conditions (temperature, time) on the AA formation. A section is also included related to AA legislation in EU and US.

Effect of Genetic Database Comprehensiveness on Fractional Proteomics of Escherichia coli O157:H7

DTIC Science & Technology

2014-01-01

proteins would be observed in the extracellular fraction. 15. SUBJECT TERMS Escherichia coli O157:H7 Liquid chromatography Mass spectrometry...Preparation ...............1 2.2 Liquid Chromatography /Mass Spectrometry Sample Preparation ....................2 2.3 Liquid Chromatography /Mass... Chromatography /Mass Spectrometry Sample Preparation. Samples were prepared for liquid chromatography tandem mass spectrometry (LC-MS/MS) in a similar

Versatile ligands for high-performance liquid chromatography: An overview of ionic liquid-functionalized stationary phases.

PubMed

Zhang, Mingliang; Mallik, Abul K; Takafuji, Makoto; Ihara, Hirotaka; Qiu, Hongdeng

2015-08-05

Ionic liquids (ILs), a class of unique substances composed purely by cation and anions, are renowned for their fascinating physical and chemical properties, such as negligible volatility, high dissolution power, high thermal stability, tunable structure and miscibility. They are enjoying ever-growing applications in a great diversity of disciplines. IL-modified silica, transforming the merits of ILs into chromatographic advantages, has endowed the development of high-performance liquid chromatography (HPLC) stationary phase with considerable vitality. In the last decade, IL-functionalized silica stationary phases have evolved into a series of branches to accommodate to different HPLC modes. An up-to-date overview of IL-immobilized stationary phases is presented in this review, and divided into five parts according to application mode, i.e., ion-exchange, normal-phase, reversed-phase, hydrophilic interaction and chiral recognition. Specific attention is channeled to synthetic strategies, chromatographic behavior and separation performance of IL-functionalized silica stationary phases. Copyright © 2015 Elsevier B.V. All rights reserved.

[Simultaneous determination of ochratoxin A, B and citrinin in foods by HPLC-FL and LC/MS/MS].

PubMed

Tabata, Setsuko; Iida, Kenji; Kimura, Keisuke; Iwasaki, Yumiko; Nakazato, Mitsuo; Kamata, Kunihiro; Hirokado, Masako

2008-04-01

Methods using high-performance liquid chromatography with fluorescence detection (HPLC-FL) and using liquid chromatography with tandem mass spectrometry (LC/MS/MS) were developed for simultaneous determination of ochratoxin A (OTA), ochratoxin B (OTB) and citrinin (CIT) in cereal, fruit, and coffee products. The samples were extracted with ethyl acetate under an acidic condition, and then cleaned up with liquid-liquid separation. The test solutions were analyzed by reverse-phase HPLC-FL and LC/MS/MS. Mass spectral acquisition was performed in positive ion mode by applying multiple reaction monitoring. The performances of both detectors were almost equivalent. The recoveries of OTA and OTB were 87-111%, and that of CIT were 70-88%. The limits of quantification (S/N> or =10) of OTA, OTB and CIT was 0.1 mug/kg or less. These methods were considered to be useful for the determination of the three mycotoxins at low levels (0.1 microg/kg).

Composition and Molecular Weight Distribution of Carob Germ Proteins Fractions

USDA-ARS?s Scientific Manuscript database

Biochemical properties of carob germ proteins were analyzed using a combination of selective extraction, reversed-phase high performance liquid chromatography (RP-HPLC), size exclusion chromatography coupled with multi-angle laser light scattering (SEC-MALS) and electrophoretic analysis. Using a mo...

Optimized method for the determination of itopride in human plasma by high-performance liquid chromatography with fluorimetric detection.

PubMed

Ptácek, Pavel; Klíma, Josef; Macek, Jan

2009-03-15

A high-performance liquid chromatographic method with fluorescence detection for the determination of itopride in human plasma is reported. The sample preparation was based on liquid-liquid extraction of itopride from plasma with t-butylmethylether and dichloromethane (70:30, v/v) mixture followed by a back extraction of the analyte to the phosphate buffer (pH 3.2). Liquid chromatography was performed on an octadecylsilica column (55 mm x 4 mm, 3 microm particles), the mobile phase consisted of acetonitrile-triethylamine-15 mM dihydrogenpotassium phosphate (14.5:0.5:85, v/v/v), pH of the mobile phase was adjusted to 4.8. The run time was 3 min. The fluorimetric detector was operated at 250/342 nm (excitation/emission wavelength). Naratriptan was used as the internal standard. The limit of quantitation was 9.5 ng/ml using 0.5 ml of plasma. The method precision and inaccuracy were less than 8%. The assay was applied to the analysis of samples from a bioequivalence study.

A Tetrodotoxin-Producing Vibrio Strain, LM-1, from the Puffer Fish Fugu vermicularis radiatus

PubMed Central

Lee, Myoung-Ja; Jeong, Dong-Youn; Kim, Woo-Seong; Kim, Hyun-Dae; Kim, Cheorl-Ho; Park, Won-Whan; Park, Yong-Ha; Kim, Kyung-Sam; Kim, Hyung-Min; Kim, Dong-Soo

2000-01-01

Identification of tetrodotoxin (TTX) and its derivatives produced from a Vibrio strain in the intestine of the puffer fish Fugu vermicularis radiatus was performed by thin-layer chromatography, electrophoresis, high-performance liquid chromatography, and gas chromatography-mass spectrometry, together with a mouse bioassay for toxicity. It was demonstrated that the isolated bacterium produced TTX, 4-epi-TTX, and anhTTX during cultivation, suggesting that Vibrio strains are responsible for the toxification of the puffer fish. PMID:10742263

[Advance in study on zearalenone's toxicity and determination].

PubMed

He, Qing-Hua; Xu, Yang

2005-07-01

The article is intended to introduce the zearalenone's toxicity, determination methods and prevention. Zearalenone is one of the most widely distributed mycotoxins produces by Fusarium Species, it is harm to animals and human. And it can induce human liver cancer,carcinoma of tesis esophagus cancer. Now we use high-performance liquid chromatography, gas chromatography, thin layer chromatography, non-toxicity determinations to detect it.

Explosives Dissolved from Unexploded Ordnance

DTIC Science & Technology

2011-10-01

production) HPLC High performance Liquid Chromatography IC Ion conductivity MMR Massachusetts Military Reservation NCDC National Climatic Data Center...rounds, 2) its dissolution rate in water can be measured using ion chromatography or electrical conductivity, and 3) it has a high water solubility...sample access 29 The water samples were analyzed with an ion chromatography system8. The conductivity of each solution is measured and compared

Rapid determination of parabens in seafood sauces by high-performance liquid chromatography: A practical comparison of core-shell particles and sub-2 μm fully porous particles.

PubMed

Ye, Jing; Cao, Xiaoji; Cheng, Zhuo; Qin, Ye; Lu, Yanbin

2015-12-01

In this work, the chromatographic performance of superficially porous particles (Halo core-shell C18 column, 50 mm × 2.1 mm, 2.7 μm) was compared with that of sub-2 μm fully porous particles (Acquity BEH C18 , 50 mm × 2.1 mm, 1.7 μm). Four parabens, methylparaben, ethylparaben, propylparaben, and butylparaben, were used as representative compounds for calculating the plate heights in a wide flow rate range and analyzed on the basis of the Van Deemter and Knox equations. Theoretical Poppe plots were constructed for each column to compare their kinetic performance. Both phases gave similar minimum plate heights when using nonreduced coordinates. Meanwhile, the flat C-term of the core-shell column provided the possibilities for applying high flow rates without significant loss in efficiency. The low backpressure of core-shell particles allowed this kind of column, especially compatible with conventional high-performance liquid chromatography systems. Based on these factors, a simple high-performance liquid chromatography method was established and validated for the determination of parabens in various seafood sauces using the Halo core-shell C18 column for separation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

21 CFR 862.2260 - High pressure liquid chromatography system for clinical use.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false High pressure liquid chromatography system for... Clinical Laboratory Instruments § 862.2260 High pressure liquid chromatography system for clinical use. (a) Identification. A high pressure liquid chromatography system for clinical use is a device intended to separate...

21 CFR 862.2260 - High pressure liquid chromatography system for clinical use.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false High pressure liquid chromatography system for... Clinical Laboratory Instruments § 862.2260 High pressure liquid chromatography system for clinical use. (a) Identification. A high pressure liquid chromatography system for clinical use is a device intended to separate...

21 CFR 862.2260 - High pressure liquid chromatography system for clinical use.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false High pressure liquid chromatography system for... Clinical Laboratory Instruments § 862.2260 High pressure liquid chromatography system for clinical use. (a) Identification. A high pressure liquid chromatography system for clinical use is a device intended to separate...

21 CFR 862.2260 - High pressure liquid chromatography system for clinical use.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false High pressure liquid chromatography system for... Clinical Laboratory Instruments § 862.2260 High pressure liquid chromatography system for clinical use. (a) Identification. A high pressure liquid chromatography system for clinical use is a device intended to separate...

21 CFR 862.2260 - High pressure liquid chromatography system for clinical use.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false High pressure liquid chromatography system for... Clinical Laboratory Instruments § 862.2260 High pressure liquid chromatography system for clinical use. (a) Identification. A high pressure liquid chromatography system for clinical use is a device intended to separate...

Screening, confirmation and quantification of boldenone sulfate in equine urine after administration of boldenone undecylenate (Equipoise).

PubMed

Weidolf, L O; Chichila, T M; Henion, J D

1988-12-09

Methods for screening by thin-layer chromatography, quantification by high-performance liquid chromatography with ultraviolet detection and confirmation by gas chromatography-mass spectrometry of boldenone sulfate in equine urine after administration of boldenone undecylenate (Equipoise) are presented. Sample work-up was done with C18 liquid-solid extraction followed by solvolytic cleavage of the sulfate ester. Confirmatory evidence of boldenone sulfate in equine urine was obtained from 2 h to 42 days following a therapeutic intramuscular dose of Equipoise. The use of 19-nortestosterone sulfate as the internal standard for quantification of boldenone sulfate is discussed.

Rapid quantification of iodopropynyl butylcarbamate as the preservative in cosmetic formulations using high-performance liquid chromatography-electrospray mass spectrometry.

PubMed

Frauen, M; Steinhart, H; Rapp, C; Hintze, U

2001-07-01

A simple, rapid and reproducible method for identification and quantification of iodopropynyl butylcarbamate (IPBC) in different cosmetic formulations is presented. The determination was carried out using a high-performance liquid chromatography (HPLC) procedure on a reversed phase column coupled to a single quadrupole mass spectrometer (MS) via an electrospray ionization (ESI) interface. Detection was performed in the positive selected ion-monitoring mode. In methanol/water extracts from different cosmetic formulations a detection limit between 50 and 100 ng/g could be achieved. A routine analytical procedure could be set up with good quantification reliability (relative standard deviation between 0.9 and 2.9%).

High-performance liquid chromatography-electrospray ionization mass spectrometry determination of sodium ferulate in human plasma.

PubMed

Yang, Cheng; Tian, Yuan; Zhang, Zunjian; Xu, Fengguo; Chen, Yun

2007-02-19

A selective and sensitive high-performance liquid chromatography-electrospray ionization mass spectrometry method has been developed for the determination of sodium ferulate in human plasma. The sample preparation was a liquid-liquid extraction and chromatographic separation was achieved with an Agilent ZORBAX SB-C(18) (3.5 microm, 100 mm x 3.0 mm) column, using a mobile phase of methanol-0.05% acetic acid 40:60 (v/v). Standard curves were linear (r(2)=0.9982) over the concentration range of 0.007-4.63 nM/ml and had acceptable accuracy and precision. The within- and between-batch precisions were within 12% relative standard deviation. The lower limit of quantification (LLOQ) was 0.007 nM/ml. The validated HPLC-ESI-MS method has been used successfully to study sodium ferulate pharmacokinetics, bioavailability and bioequivalence in 20 healthy volunteers.

A simple, sensitive determination of ganciclovir in infant plasma by high-performance liquid chromatography with fluorescence detection.

PubMed

Yoshida, Terumitsu; Takahashi, Ryohei; Imai, Koichi; Uchida, Hiroshi; Arai, Yasutoshi; Oh-ishi, Tsutomu

2010-03-01

This study developed a simple and sensitive method using reversed-phase high-performance liquid chromatography (HPLC) for ganciclovir (GCV) plasma concentrations in cytomegalovirus infectious infants with hearing loss. The method involves a simple protein precipitation procedure that uses no solid-phase or liquid-liquid extraction. The HPLC separation was carried out on a Cadenza CD-C(18) column (3 microm, 4.6 mm x 150 mm) with phosphate buffer (pH 2.5, 25 mM) containing 1% methanol-acetonitrile mixture (4:3, v/v) as a mobile phase at a 0.7 mL/min flow rate. GCV was detected using a fluorescence detection (lambdaex/em: 265/380 nm). The quantification limit was 0.025 microg/mL for 100 microL of plasma sample at which good intra- and inter-assay coefficient of variation values (< 4.96%) and recoveries (94.9-96.5%) were established.

Optimization of ultra-performance liquid chromatography (UPLC) with fluorescence detector (FLD) method for the quantitative determination of selected neurotransmitters in rat brain.

PubMed

Stragierowicz, Joanna; Daragó, Adam; Brzeźnicki, Sławomir; Kilanowicz, Anna

2017-07-26

Glutamate (Glu) and γ-aminobutyric acid (GABA) are the main neurotransmitters in the central nervous system for excitatory and inhibitory processes, respectively. Monitoring these neurotransmitters is an essential tool in establishing pathological functions, among others in terms of occupational exposure to toxic substances. We present modification of the HPLC (high-performance liquid chromatography) to the UPLC (ultra-performance liquid chromatography) method for the simultaneous determination of glutamate and γ-aminobutyric acid in a single injection. The isocratic separation of these neurotransmitter derivatives was performed on Waters Acquity BEH (ethylene bridged hybrid) C18 column with particle size of 1.7 μm at 35°C using a mobile phase consisting of 0.1 M acetate buffer (pH 6.0) and methanol (60:40, v/v) at a flow rate of 0.3 ml/min. The analytes were detected with the fluorescence detector (FLD) using derivatization with o-phthaldialdehyde (OPA), resulting in excitation at 340 nm and emission at 455 nm. Several validation parameters including linearity (0.999), accuracy (101.1%), intra-day precision (1.52-1.84%), inter-day precision (2.47-3.12%), limit of detection (5-30 ng/ml) and quantification (100 ng/ml) were examined. The developed method was also used for the determination of these neurotransmitters in homogenates of selected rat brain structures. The presented UPLC-FLD is characterized by shorter separation time (3.5 min), which is an adaptation of the similar HPLC methods and is an alternative for more expensive references techniques such as liquid chromatography coupled with tandem mass-spectrometry (LC-MS/MS) methods. Med Pr 2017;68(5):583-591. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Self-assembled cyclodextrin-modified gold nanoparticles on silica beads as stationary phase for chiral liquid chromatography and hydrophilic interaction chromatography.

PubMed

Li, Yuanyuan; Wei, Manman; Chen, Tong; Zhu, Nan; Ma, Yulong

2016-11-01

A facile strategy based on self-assembly of Au nanoparticles (AuNPs) (60±10nm in size) on the surfaces of amino-functionalized porous silica spheres under mild conditions was proposed. The resulting material possessed a core-shell structure in which AuNPs were the shell and silica spheres were the core. Then, thiolated-β-cyclodextrin (SH-β-CD) was covalently attached onto the AuNPs as chiral selector for the enantioseparation. The resultant packing material was evaluated by high-performance liquid chromatography (HPLC). The separations of nine pairs of enantiomers were achieved by using the new chiral stationary phase (CSP) in the reversed-phase liquid chromatography (RPLC) mode, respectively. The results showed the new CSP have more sufficient interaction with the analytes due to the existence of AuNPs on silica surfaces, resulting in faster mass transfer rate, compared with β-CD modified silica column. The result shed light on potential usage of chemical modified NPs as chiral selector for enantioseparation based on HPLC. In addition, the new phase was also used in hydrophilic interaction liquid chromatography (HILIC) to separate polar compounds and highly hydrophilic compounds. Copyright © 2016 Elsevier B.V. All rights reserved.

Modern separation techniques coupled to high performance mass spectrometry for glycolipid analysis.

PubMed

Sarbu, Mirela; Zamfir, Alina Diana

2018-01-21

Glycolipids (GLs), involved in biological processes and pathologies, such as viral, neurodegenerative and oncogenic transformations are in the focus of research related to method development for structural analysis. This review highlights modern separation techniques coupled to mass spectrometry (MS) for the investigation of GLs from various biological matrices. First section is dedicated to methods, which, although provide the separation in a non-liquid phase, are able to supply important data on the composition of complex mixtures. While classical thin layer chromatography (TLC) is useful for MS analyses of the fractionated samples, ultramodern ion mobility (IMS) characterized by high reproducibility facilitates to discover minor species and to apply low sample amounts, in addition to providing conformational separation with isomer discrimination. Second section highlights the advantages, applications and limitations of liquid-based separation techniques such as high performance liquid chromatography (HPLC) and hydrophilic interaction liquid chromatography (HILIC) in direct or indirect coupling to MS for glycolipidomics surveys. The on- and off-line capillary electrophoresis (CE) MS, offering a remarkable separation efficiency of GLs is also presented and critically assessed from the technical and application perspective in the final part of the review. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation and application of microwave-assisted extraction and dispersive liquid-liquid microextraction followed by high-performance liquid chromatography for the determination of polar heterocyclic aromatic amines in hamburger patties.

PubMed

Aeenehvand, Saeed; Toudehrousta, Zahra; Kamankesh, Marzieh; Mashayekh, Morteza; Tavakoli, Hamid Reza; Mohammadi, Abdorreza

2016-01-01

This study developed an analytical method based on microwave-assisted extraction and dispersive liquid-liquid microextraction followed by high-performance liquid chromatography for the determination of three polar heterocyclic aromatic amines from hamburger patties. Effective parameters controlling the performance of the microextraction process, such as the type and volume of extraction and disperser solvents, microwave time, nature of alkaline aqueous solution, pH and salt amount, were optimized. The calibration graphs were linear in the range of 1-200 ng g(-1), with a coefficient of determination (R(2)) better than 0.9993. The relative standard deviations (RSD) for seven analyses were between 3.2% and 6.5%. The recoveries of those compounds in hamburger patties were from 90% to 105%. Detection limits were between 0.06 and 0.21 ng g(-1). A comparison of the proposed method with the existing literature demonstrates that it is a simple, rapid, highly selective and sensitive, and it gives good enrichment factors and detection limits for determining HAAs in real hamburger patties samples. Copyright © 2015 Elsevier Ltd. All rights reserved.

Integration of electrochemistry with ultra-performance liquid chromatography/mass spectrometry.

PubMed

Cai, Yi; Zheng, Qiuling; Liu, Yong; Helmy, Roy; Loo, Joseph A; Chen, Hao

2015-01-01

This study presents the development of ultra-performance liquid chromatography (UPLC) mass spectrometry (MS) combined with electrochemistry (EC) for the first time and its application for the structural analysis of proteins/peptides that contain disulfide bonds. In our approach, a protein/peptide mixture sample undergoes a fast UPLC separation and subsequent electrochemical reduction in an electrochemical flow cell followed by online MS and tandem mass spectrometry (MS/MS) analyses. The electrochemical cell is coupled to the mass spectrometer using our recently developed desorption electrospray ionization (DESI) interface. Using this UPLC/EC/DESI-MS method, peptides that contain disulfide bonds can be differentiated from those without disulfide bonds, as the former are electroactive and reducible. MS/MS analysis of the disulfide-reduced peptide ions provides increased information on the sequence and disulfide-linkage pattern. In a reactive DESI- MS detection experiment in which a supercharging reagent was used to dope the DESI spray solvent, increased charging was obtained for the UPLC-separated proteins. Strikingly, upon online electrolytic reduction, supercharged proteins (e.g., α-lactalbumin) showed even higher charging, which will be useful in top- down protein structure MS analysis as increased charges are known to promote protein ion dissociation. Also, the separation speed and sensitivity are enhanced by approximately 1(~)2 orders of magnitude by using UPLC for the liquid chromatography (LC)/EC/MS platform, in comparison to the previously used high- performance liquid chromatography (HPLC). This UPLC/EC/DESI-MS method combines the power of fast UPLC separation, fast electrochemical conversion, and online MS structural analysis for a potentially valuable tool for proteomics research and bioanalysis.

Additional band broadening of peptides in the first size-exclusion chromatographic dimension of an automated stop-flow two-dimensional high performance liquid chromatography.

PubMed

Xu, Jucai; Sun-Waterhouse, Dongxiao; Qiu, Chaoying; Zhao, Mouming; Sun, Baoguo; Lin, Lianzhu; Su, Guowan

2017-10-27

The need to improve the peak capacity of liquid chromatography motivates the development of two-dimensional analysis systems. This paper presented a fully automated stop-flow two-dimensional liquid chromatography system with size exclusion chromatography followed by reversed phase liquid chromatography (SEC×RPLC) to efficiently separate peptides. The effects of different stop-flow operational parameters (stop-flow time, peak parking position, number of stop-flow periods and column temperature) on band broadening in the first dimension (1 st D) SEC column were quantitatively evaluated by using commercial small proteins and peptides. Results showed that the effects of peak parking position and the number of stop-flow periods on band broadening were relatively small. Unlike stop-flow analysis of large molecules with a long running time, additional band broadening was evidently observed for small molecule analytes due to the relatively high effective diffusion coefficient (D eff ). Therefore, shorter analysis time and lower 1 st D column temperature were suggested for analyzing small molecules. The stop-flow two-dimensional liquid chromatography (2D-LC) system was further tested on peanut peptides and an evidently improved resolution was observed for both stop-flow heart-cutting and comprehensive 2D-LC analysis (in spite of additional band broadening in SEC). The stop-flow SEC×RPLC, especially heart-cutting analysis with shorter analysis time and higher 1 st D resolution for selected fractions, offers a promising approach for efficient analysis of complex samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Determination of capsaicinoids in topical cream by liquid-liquid extraction and liquid chromatography.

PubMed

Kaale, Eliangiringa; Van Schepdael, Ann; Roets, Eugène; Hoogmartens, Jos

2002-11-07

A reversed-phase liquid chromatography (LC) method has been developed, optimised and validated for the separation and quantitation of capsaicin (CP) and dihydrocapsaicin (DHCP) in a topical cream formulation. Sample preparation involves liquid-liquid extraction prior to LC analysis. The method uses a Hypersil C(18) BDS, 5 micrometer, 250x4.6 mm I.D. column maintained at 35 degrees C. The mobile phase comprises methanol, water, acetonitrile (ACN) and acetic acid (47:42:10:1, v/v/v/v) at a flow rate of 1.0 ml/min. Robustness was evaluated by performing a central composite face-centred design (CCF) experiment. The method shows good selectivity, linearity, sensitivity and repeatability. The conditions allow the separation and quantitation of CP and DHCP without interference from the other substances contained in the cream.

Rapid and reliable quantitation of amino acids and myo-inositol in mouse brain by high performance liquid chromatography and tandem mass spectrometry.

PubMed

Bathena, Sai P; Huang, Jiangeng; Epstein, Adrian A; Gendelman, Howard E; Boska, Michael D; Alnouti, Yazen

2012-04-15

Amino acids and myo-inositol have long been proposed as putative biomarkers for neurodegenerative diseases. Accurate measures and stability have precluded their selective use. To this end, a sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method based on multiple reaction monitoring was developed to simultaneously quantify glutamine, glutamate, γ-aminobutyric acid (GABA), aspartic acid, N-acetyl aspartic acid, taurine, choline, creatine, phosphocholine and myo-inositol in mouse brain by methanol extractions. Chromatography was performed using a hydrophilic interaction chromatography silica column within in a total run time of 15 min. The validated method is selective, sensitive, accurate, and precise. The method has a limit of quantification ranging from 2.5 to 20 ng/ml for a range of analytes and a dynamic range from 2.5-20 to 500-4000 ng/ml. This LC-MS/MS method was validated for biomarker discovery in models of human neurological disorders. Copyright © 2012 Elsevier B.V. All rights reserved.

Qualitative and Quantitative Analysis of Volatile Components of Zhengtian Pills Using Gas Chromatography Mass Spectrometry and Ultra-High Performance Liquid Chromatography.

PubMed

Liu, Cui-Ting; Zhang, Min; Yan, Ping; Liu, Hai-Chan; Liu, Xing-Yun; Zhan, Ruo-Ting

2016-01-01

Zhengtian pills (ZTPs) are traditional Chinese medicine (TCM) which have been commonly used to treat headaches. Volatile components of ZTPs extracted by ethyl acetate with an ultrasonic method were analyzed by gas chromatography mass spectrometry (GC-MS). Twenty-two components were identified, accounting for 78.884% of the total components of volatile oil. The three main volatile components including protocatechuic acid, ferulic acid, and ligustilide were simultaneously determined using ultra-high performance liquid chromatography coupled with diode array detection (UHPLC-DAD). Baseline separation was achieved on an XB-C18 column with linear gradient elution of methanol-0.2% acetic acid aqueous solution. The UHPLC-DAD method provided good linearity (R (2) ≥ 0.9992), precision (RSD < 3%), accuracy (100.68-102.69%), and robustness. The UHPLC-DAD/GC-MS method was successfully utilized to analyze volatile components, protocatechuic acid, ferulic acid, and ligustilide, in 13 batches of ZTPs, which is suitable for discrimination and quality assessment of ZTPs.

A combined A431 cell membrane chromatography and online high performance liquid chromatography/mass spectrometry method for screening compounds from total alkaloid of Radix Caulophylli acting on the human EGFR.

PubMed

Sun, Meng; Ren, Jing; Du, Hui; Zhang, Yanmin; Zhang, Jie; Wang, Sicen; He, Langchong

2010-10-15

We have developed an online analytical method that combines A431 cell membrane chromatography (A431/CMC) with high performance liquid chromatography and mass spectrometry (LC/MS) for identifying active components from Radix Caulophylli acting on human EGFR. Retention fractions on A431/CMC model were captured onto an enrichment column and the components were directly analyzed by combining a 10-port column switcher with an LC/MS system for separation and preliminary identification. Using Sorafenib tosylate as a positive control, taspine and caulophine from Radix Caulophylli were identified as the active molecules which could act on the EGFR. This A431/CMC-online-LC/MS method can be applied for screening active components acting on EGFR from traditional Chinese medicines exemplified by Radix Caulophylli and will be of great utility in drug discovery using natural medicinal herbs as a source of novel compounds. Copyright © 2010 Elsevier B.V. All rights reserved.

Determination of 17-oxosteroid glucuronides and sulfates in urine and serum by fluorescence high-performance liquid chromatography using dansyl hydrazine as a prelabeling reagent.

PubMed

Kawasaki, T; Maeda, M; Tsuji, A

1982-12-10

A fluorescence high-performance liquid chromatographic method is described for the direct determination of conjugated 17-oxosteroids in biological fluids without hydrolysis. Conjugated 17-oxosteroids are extracted with Sep-Pak C18 cartridge, labeled with dansyl hydrazine in trichloroacetic acid--benzene solution and then separated by high-performance liquid chromatography on reversed-phase muBondapak C18 column using 0.01 M sodium acetate in methanol-water-acetic acid (65:35:1, v/v) as the mobile phase. The eluate is monitored by a fluorophotometer at 365 nm (excitation) and 520 nm (emission). Linearities of fluorescence intensities (peak heights) with the amounts of various conjugated 17-oxosteroids were obtained between 10 pmol and 100 pmol. This method is sensitive, reliable and useful for the simultaneous determination of conjugated 17-oxosteroids in urine and serum.

The determination and quantification of photosynthetic pigments by reverse phase high-performance liquid chromatography, thin-layer chromatography, and spectrophotometry.

PubMed

Pocock, Tessa; Król, Marianna; Huner, Norman P A

2004-01-01

Chorophylls and carotenoids are functionally important pigment molecules in photosynthetic organisms. Methods for the determination of chlorophylls a and b, beta-carotene, neoxanthin, and the pigments that are involved in photoprotective cycles such as the xanthophylls are discussed. These cycles involve the reversible de-epoxidation of violaxanthin into antheraxanthin and zeaxanthin, as well as the reversible de-epoxidation of lutein-5,6-epoxide into lutein. This chapter describes pigment extraction procedures from higher plants and green algae. Methods for the determination and quantification using high-performance liquid chromatograpy (HPLC) are described as well as methods for the separation and purification of pigments for use as standards using thin-layer chromatography (TLC). In addition, several spectrophotometric methods for the quantification of chlorophylls a and b are described.

Paired-ion chromatography and high performance liquid chromatography of labetalol in feeds.

PubMed

Townley, E R; Ross, B

1980-11-01

A high performance liquid chromatographic (HPLC) method using reverse phase paired-ion chromatography and ultraviolet detection at 280 nm has been developed to determine labetalol, an alpha and beta adrenoceptor blocking agent, in Purina No. 5001 rodent chow. The method is simple and rapid, and demonstrates a separation technique applicable to other acidic and basic drugs. It requires only extraction of the drug with methanol--water--acetic acid (66 + 33 + 1) and separation of insoluble material by filtration before HPLC. Labetalol, is chromatographically separated from soluble feed components by means of a microBondapak C18 column and methanol--water--acetic acid (66 + 33 + 1) mobile phase, 0.005M with respect to sodium dioctylsulfosuccinate paired-ion reagent. Average recovery is 98.7% with a relative standard deviation of +/- 2.3% for the equipment described.

Single cell-based analysis of torenia petal pigments by a combination of ArF excimer laser micro sampling and nano-high performance liquid chromatography (HPLC)-mass spectrometry.

PubMed

Kajiyama, Shin'ichiro; Harada, Kazuo; Fukusaki, Eiichiro; Kobayashi, Akio

2006-12-01

The molecular constituents of the petal pigments of the Torenia plant (Torenia hybrida) were analyzed on a single-cell basis by a combination of newly developed laser-microsampling and nano-flow liquid chromatography-electro spray ionization mass spectrometry (LC-ESIMS) techniques. Our method should provide a facile method for obtaining precise metabolic profiles of each cell in a single plant tissue.

Summer Research Program (1992). Summer Faculty Research Program (SFRP) Reports. Volume 6. Arnold Engineering Development Center, Civil Engineering Laboratory, Frank J. Seiler Research Laboratory, Wilford Hall Medical Center

DTIC Science & Technology

1992-12-01

concentrations of DNT, its degradation intermediate 4-methyl 5- nitrocatechol, and TNT were determined by high pressure liquid chromatography (HPLC...to more cost-effective site characterization and cleanup. Many such studies have been performed using chromatography and/or liquid scintillation...volume set that summarizes the research accomplishments of faculty, graduate student, and high school participants in the 1992 AFOSR Summer Research

Quantitative analysis of benzodiazepines in vitreous humor by high-performance liquid chromatography

PubMed Central

Bazmi, Elham; Behnoush, Behnam; Akhgari, Maryam; Bahmanabadi, Leila

2016-01-01

Objective: Benzodiazepines are frequently screened drugs in emergency toxicology, drugs of abuse testing, and in forensic cases. As the variations of benzodiazepines concentrations in biological samples during bleeding, postmortem changes, and redistribution could be biasing forensic medicine examinations, hence selecting a suitable sample and a validated accurate method is essential for the quantitative analysis of these main drug categories. The aim of this study was to develop a valid method for the determination of four benzodiazepines (flurazepam, lorazepam, alprazolam, and diazepam) in vitreous humor using liquid–liquid extraction and high-performance liquid chromatography. Methods: Sample preparation was carried out using liquid–liquid extraction with n-hexane: ethyl acetate and subsequent detection by high-performance liquid chromatography method coupled to diode array detector. This method was applied to quantify benzodiazepines in 21 authentic vitreous humor samples. Linear curve for each drug was obtained within the range of 30–3000 ng/mL with coefficient of correlation higher than 0.99. Results: The limit of detection and quantitation were 30 and 100 ng/mL respectively for four drugs. The method showed an appropriate intra- and inter-day precision (coefficient of variation < 10%). Benzodiazepines recoveries were estimated to be over 80%. The method showed high selectivity; no additional peak due to interfering substances in samples was observed. Conclusion: The present method was selective, sensitive, accurate, and precise for the quantitative analysis of benzodiazepines in vitreous humor samples in forensic toxicology laboratory. PMID:27635251

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.

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

PubMed

Baghdady, Yehia Z; Schug, Kevin A

2016-01-01

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

Measurement of serum 3-epi-25-hydroxyvitamin D3, 25-hydroxyvitamin D3 and 25-hydroxyvitamin D2 in infant, paediatric and adolescent populations of Korea using ultra-performance liquid chromatography-tandem mass spectrometry.

PubMed

Cho, Sung E; Kim, Sollip; Kim, Young D; Lee, Hyojung; Seo, Dong H; Song, Junghan; Um, Tae H; Cho, Chong R; Kim, Nam H; Hwang, Jong H

2017-09-01

Background We evaluated the performance of ultra-performance liquid chromatography-tandem mass spectrometry to measure serum 3-epi-25-hydroxyvitamin D 3 , 25-hydroxyvitamin D 3 and 25-hydroxyvitamin D 2 concentrations in 519 infant, paediatric and adolescent serum samples in Korea. Methods We used a Kinetex XB-C18 column and isocratic methanol/water (77.5/22.5, v/v) with 0.025% (v/v) high-performance liquid chromatography solvent additive flowing at 0.25 mL/min, yielding an 11 min/sample run time. A TQD triple quadrupole mass spectrometer in electrospray ionization positive ion mode with multiple reaction monitoring transition via an MSMS vitamin D kit was used to evaluate precision, carryover, ion suppression and linearity. Samples were prepared using the 4-phenyl-1,2,4-triazoline-3,5-dione derivatization method. Results Intra- and inter-run precisions were 1.23-13.28% and 1.02-10.08%, respectively. Group carryovers were -0.27% and 0.10%, respectively. There was no ion suppression. The calibration curve showed good linearity from calibrator Level 1 (11.75 nmol/L) to 6 (375 nmol/L) with R 2  > 0.9999. The 3-epi-25-hydroxyvitamin D 3 and 25-hydroxyvitamin D 3 peaks were clearly separated in the extracted ion chromatogram. Infant serum samples 3-epi-25-hydroxyvitamin D 3 concentrations were significantly higher than paediatric and adolescent concentrations. Conclusions The ultra-performance liquid chromatography-tandem mass spectrometry assay performed acceptably, clearly separating 3-epi-25-hydroxyvitamin D 3 from 25-hydroxyvitamin D 3 . High 3-epi-25-hydroxyvitamin D 3 concentrations were observed in infant but not in paediatric and adolescent serum samples.

Development of anion-exchange/reversed-phase high performance liquid chromatography-inductively coupled plasma-mass spectrometry methods for the speciation of bio-available iodine and bromine from edible seaweed.

PubMed

Romarís-Hortas, Vanessa; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Antonio

2012-05-04

Anion exchange high performance liquid chromatography hyphenated with inductively coupled plasma-mass spectrometry has been novelly applied to assess inorganic (iodide and iodate) and organic (3-iodotyrosine - MIT, and 3,5-diiodotyrosine - DIT) iodine species in a single chromatographic run. The optimized operating conditions (Dionex IonPac AS7, gradient elution with 175 mM ammonium nitrate plus 15% (v/v) methanol, pH 3.8, as a mobile phase and flow rates within the 0.5-1.5 mL min(-1) range) have also been used to perform inorganic bromine speciation analysis (bromide and bromate). The developed method has been applied for determining the bio-available contents of iodine and bromine species in dialyzates from edible seaweed. Reverse phase high performance liquid chromatography (Zorbax Eclipse XDB-C8, gradient elution with 0.2% (m/m) acetic acid, and 0.2% (m/m) acetic acid in methanol, as mobile phases, and a constant flow rate of 0.75 mL min(-1)) also hyphenated with inductively coupled plasma-mass spectrometry was used to confirm the presence of organic iodine species (MIT and DIT) in the dialyzates. The verification of the presence of iodinated amino acids (MIT and DIT) in the extracts was also performed by reverse phase high performance liquid chromatography-electrospray ionization-mass spectrometry (LTQ Orbitrap). The developed methods have provided good repeatability (RSD values lower than 10% for both anion exchange and reverse phase separations) and analytical recoveries within the 90-105% range for all cases. The in vitro bio-availability method consisted of a simulated gastric and an intestinal digestion/dialysis (10 kDa molecular weight cut-off - MWCO) two-stage procedure. Iodide and MIT were the main bio-available species quantified, whereas bromide was the major bromine species found in the extracts. Copyright © 2012 Elsevier B.V. All rights reserved.

Indirect ultraviolet detection of alkaline earth metal ions using an imidazolium ionic liquid as an ultraviolet absorption reagent in ion chromatography.

PubMed

Liu, Yong-Qiang; Yu, Hong

2017-04-01

A convenient and versatile method was developed for the separation and detection of alkaline earth metal ions by ion chromatography with indirect UV detection. The chromatographic separation of Mg 2+ , Ca 2+ , and Sr 2+ was performed on a carboxylic acid base cation exchange column using imidazolium ionic liquid/acid as the mobile phase, in which the imidazolium ionic liquid acted as an UV-absorption reagent. The effects of imidazolium ionic liquids, detection wavelength, acids in the mobile phase, and column temperature on the retention of Mg 2+ , Ca 2+ , and Sr 2+ were investigated. The main factors influencing the separation and detection were the background UV absorption reagent and the concentration of hydrogen ion in ion chromatography with indirect UV detection. The successful separation and detection of Mg 2+ , Ca 2+ , and Sr 2+ within 14 min were achieved using the selected chromatographic conditions, and the detection limits (S/N = 3) were 0.06, 0.12, and 0.23 mg/L, respectively. A new separation and detection method of alkaline earth metal ions by ion chromatography with indirect UV detection was developed, and the application range of ionic liquids was expanded. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preconcentration and determination of ceftazidime in real samples using dispersive liquid-liquid microextraction and high-performance liquid chromatography with the aid of experimental design.

PubMed

Razmi, Rasoul; Shahpari, Behrouz; Pourbasheer, Eslam; Boustanifar, Mohammad Hasan; Azari, Zhila; Ebadi, Amin

2016-11-01

A rapid and simple method for the extraction and preconcentration of ceftazidime in aqueous samples has been developed using dispersive liquid-liquid microextraction followed by high-performance liquid chromatography analysis. The extraction parameters, such as the volume of extraction solvent and disperser solvent, salt effect, sample volume, centrifuge rate, centrifuge time, extraction time, and temperature in the dispersive liquid-liquid microextraction process, were studied and optimized with the experimental design methods. Firstly, for the preliminary screening of the parameters the taguchi design was used and then, the fractional factorial design was used for significant factors optimization. At the optimum conditions, the calibration curves for ceftazidime indicated good linearity over the range of 0.001-10 μg/mL with correlation coefficients higher than the 0.98, and the limits of detection were 0.13 and 0.17 ng/mL, for water and urine samples, respectively. The proposed method successfully employed to determine ceftazidime in water and urine samples and good agreement between the experimental data and predictive values has been achieved. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rapid determination of quinolones in cosmetic products by ultra high performance liquid chromatography with tandem mass spectrometry.

PubMed

Liu, Shao-Ying; Huang, Xi-Hui; Wang, Xiao-Fang; Jin, Quan; Zhu, Guo-Nian

2014-05-01

This study developed an improved analytical method for the simultaneous quantification of 13 quinolones in cosmetics by ultra high performance liquid chromatography combined with ESI triple quadrupole MS/MS under the multiple reaction monitoring mode. The analytes were extracted and purified by using an SPE cartridge. The limits of quantification ranged from 0.03 to 3.02 μg/kg. The precision for determining the quinolones was <19.39%. The proposed method was successfully developed for the determination of quinolones in real cosmetic samples. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sensitive analysis of blonanserin, a novel antipsychotic agent, in human plasma by ultra-performance liquid chromatography-tandem mass spectrometry.

PubMed

Ogawa, Tadashi; Hattori, Hideki; Kaneko, Rina; Ito, Kenjiro; Iwai, Masayo; Mizutani, Yoko; Arinobu, Tetsuya; Ishii, Akira; Suzuki, Osamu; Seno, Hiroshi

2010-01-01

A rapid and sensitive method for analysis of blonanserin in human plasma by ultra-performance liquid chromatography-tandem mass spectrometry is presented. After pretreatment of a plasma sample by solid-phase extraction, blonanserin was analyzed by the system with a C(18) column. This method gave satisfactory recovery rates, reproducibility, and good linearity of calibration curve in the range of 0.01-10.0 ng/mL for quality control samples spiked with blonanserin. The detection limit was as low as 1 pg/mL. This method seems very useful in forensic and clinical toxicology and pharmacokinetic studies.

High-Performance Liquid Chromatography (HPLC)-Based Detection and Quantitation of Cellular c-di-GMP.

PubMed

Petrova, Olga E; Sauer, Karin

2017-01-01

The modulation of c-di-GMP levels plays a vital role in the regulation of various processes in a wide array of bacterial species. Thus, investigation of c-di-GMP regulation requires reliable methods for the assessment of c-di-GMP levels and turnover. Reversed-phase high-performance liquid chromatography (RP-HPLC) analysis has become a commonly used approach to accomplish these goals. The following describes the extraction and HPLC-based detection and quantification of c-di-GMP from Pseudomonas aeruginosa samples, a procedure that is amenable to modifications for the analysis of c-di-GMP in other bacterial species.

Determination of vitamins D2 and D3 in selected food matrices by online high-performance liquid chromatography-gas chromatography-mass spectrometry (HPLC-GC-MS).

PubMed

Nestola, Marco; Thellmann, Andrea

2015-01-01

An online normal-phase liquid chromatography-gas chromatography-mass spectrometry (HPLC-GC-MS) method was developed for the determination of vitamins D2 and D3 in selected food matrices. Transfer of the sample from HPLC to GC was realized by large volume on-column injection; detection was performed with a time-of-flight mass spectrometer (TOF-MS). Typical GC problems in the determination of vitamin D such as sample degradation or sensitivity issues, previously reported in the literature, were not observed. Determination of total vitamin D content was done by quantitation of its pyro isomer based on an isotopically labelled internal standard (ISTD). Extracted ion traces of analyte and ISTD showed cross-contribution, but non-linearity of the calibration curve was not determined inside the chosen calibration range by selection of appropriate quantifier ions. Absolute limits of detection (LOD) and quantitation (LOQ) for vitamins D2 and D3 were calculated as approximately 50 and 150 pg, respectively. Repeatability with internal standard correction was below 2 %. Good agreement between quantitative results of an established high-performance liquid chromatography with UV detection (HPLC-UV) method and HPLC-GC-MS was found. Sterol-enriched margarine was subjected to HPLC-GC-MS and HPLC-MS/MS for comparison, because HPLC-UV showed strong matrix interferences. HPLC-GC-MS produced comparable results with less manual sample cleanup. In summary, online hyphenation of HPLC and GC allowed a minimization in manual sample preparation with an increase of sample throughput.

Determination of quantitative retention-activity relationships between pharmacokinetic parameters and biological effectiveness fingerprints of Salvia miltiorrhiza constituents using biopartitioning and microemulsion high-performance liquid chromatography.

PubMed

Gao, Haoshi; Huang, Hongzhang; Zheng, Aini; Yu, Nuojun; Li, Ning

2017-11-01

In this study, we analyzed danshen (Salvia miltiorrhiza) constituents using biopartitioning and microemulsion high-performance liquid chromatography (MELC). The quantitative retention-activity relationships (QRARs) of the constituents were established to model their pharmacokinetic (PK) parameters and chromatographic retention data, and generate their biological effectiveness fingerprints. A high-performance liquid chromatography (HPLC) method was established to determine the abundance of the extracted danshen constituents, such as sodium danshensu, rosmarinic acid, salvianolic acid B, protocatechuic aldehyde, cryptotanshinone, and tanshinone IIA. And another HPLC protocol was established to determine the abundance of those constituents in rat plasma samples. An experimental model was built in Sprague Dawley (SD) rats, and calculated the corresponding PK parameterst with 3P97 software package. Thirty-five model drugs were selected to test the PK parameter prediction capacities of the various MELC systems and to optimize the chromatographic protocols. QRARs and generated PK fingerprints were established. The test included water/oil-soluble danshen constituents and the prediction capacity of the regression model was validated. The results showed that the model had good predictability. Copyright © 2017. Published by Elsevier B.V.

Rapid characterization of the chemical constituents of Sijunzi decoction by UHPLC coupled with Fourier transform ion cyclotron resonance mass spectrometry.

PubMed

Guan, Zhibo; Wang, Miao; Cai, Yi; Yang, Hongmei; Zhao, Min; Zhao, Chunjie

2018-06-01

Sijunzi decoction, a renowned Chinese prescription has long been utilized to treat gastrointestinal problems. In the context of this research work, the use of Ultra high performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry was made to separate and characterize the components of Sijunzi decoction. The performance of Liquid chromatography was carried out on a C8 column (150 mm × 2.1 mm, 1.8 μm); moreover, the mobile phase were consisted of 0.2% formic acid (A) and acetonitrile (B). In accordance with the findings, characterization of 120 chemical compounds was performed by liquid chromatography with mass spectrometry. The key constituents among them included ginsenosides (in Radix Ginseng), 16 triterpene carboxylic acids (in Poria), sesquiterpenes (in Rhizoma Atractylodis Macrocephalae), triterpenesaponins (in Glycyrrhizae Radix et Rhizoma Praeparata Cum Melle) as well as flavonoids (in Glycyrrhizae Radix et Rhizoma Praeparata Cum Melle) in Sijunzi decoction. This research developed the bases for prospective research associated with Sijunzi decoction, together with being expected to be useful to rapidly extract and characterize the constituents in other Traditional Chinese herbal formulations. Copyright © 2018 Elsevier B.V. All rights reserved.

Rapid separation and characterization of diterpenoid alkaloids in processed roots of Aconitum carmichaeli using ultra high performance liquid chromatography coupled with hybrid linear ion trap-Orbitrap tandem mass spectrometry.

PubMed

Xu, Wen; Zhang, Jing; Zhu, Dayuan; Huang, Juan; Huang, Zhihai; Bai, Junqi; Qiu, Xiaohui

2014-10-01

The lateral root of Aconitum carmichaeli, a popular traditional Chinese medicine, has been widely used to treat rheumatic diseases. For decades, diterpenoid alkaloids have dominated the phytochemical and biomedical research on this plant. In this study, a rapid and sensitive method based on ultra high performance liquid chromatography coupled with linear ion trap-Orbitrap tandem mass spectrometry was developed to characterize the diterpenoid alkaloids in Aconitum carmichaeli. Based on an optimized chromatographic condition, more than 120 diterpenoid alkaloids were separated with good resolution. Using a systematic strategy that combines high resolution separation, highly accurate mass measurements and a good understanding of the diagnostic fragment-based fragmentation patterns, these diterpenoid alkaloids were identified or tentatively identified. The identification of these chemicals provided essential data for further phytochemical studies and toxicity research of Aconitum carmichaeli. Moreover, the ultra high performance liquid chromatography with linear ion trap-Orbitrap mass spectrometry platform was an effective and accurate tool for rapid qualitative analysis of secondary metabolite productions from natural resources. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Validated HPLC Determination of 4-Dimethylaminoantipyrine in Different Suppository Bases

PubMed Central

Kalmár, É; Kormányos, B.; Szakonyi, G.; Dombi, G.

2014-01-01

Suppositories are important tools for individual therapy, especially in paediatrics, and an instrumental assay method has become necessary for the quality control of dosage units. The aim of this work was to develop a rapid, effective high-performance liquid chromatography method to assay aminophenazone in extemporaneous suppositories prepared with two different suppository bases, adeps solidus and massa macrogoli. With a novel sample preparation method developed by the authors, 4-dimethylaminoantipyrine was determined in these suppository bases with 95-105% recovery. The measurements were carried out on a Shimadzu Prominence ultra high-performance liquid chromatography system equipped with a 20 μl sample loop. The separation was achieved on a Hypersil ODS column, with methanol, sodium acetate buffer (pH 5.5±0.05, 0.05 M, 60:40, v/v) as the mobile phase at a flow rate of 1.5 ml/min. The chromatograms were acquired at 253 nm. The chromatographic method was fully validated in accordance with current guidelines. The presented data demonstrate the successful development of a rapid, efficient and robust sample preparation and high-performance liquid chromatography method for the routine quality control of the dosage units of suppositories containing 4-dimethylaminoantipyrine. PMID:24799736

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...

A simple, rapid and novel method based on salting-out assisted liquid-liquid extraction for ochratoxin A determination in beer samples prior to ultra-high performance liquid chromatography coupled to tandem mass spectrometry.

PubMed

Mariño-Repizo, Leonardo; Goicoechea, Hector; Raba, Julio; Cerutti, Soledad

2018-06-07

A novel, simple, easy and cheap sample treatment strategy based on salting-out assisted liquid-liquid extraction (SALLE) for ochratoxin A (OTA) ultra-trace analysis in beer samples using ultra-high performance liquid chromatography-tandem mass spectrometry determination was developed. The factors involved in the efficiency of pretreatment were studied employing factorial design in the screening phase and the optimal conditions of the significant variables on the analytical response were evaluated using a central composite face-centred design (CCF). Consequently, the amount of salt ((NH 4 ) 2 SO 4 ), together with the volumes of sample, hydrophilic (acetone) and nonpolar (toluene) solvents, and times of vortexing and centrifugation were optimized. Under optimized conditions, the limits of detection (LOD) and quantification (LOQ) were 0.02 µg l -1 and 0.08 µg l -1 respectively. OTA extraction recovery by SALLE was approximately 90% (0.2 µg l -1 ). Furthermore, the methodology was in agreement with EU Directive requirements and was successfully applied for analysis of beer samples.

Facile and sensitive determination of N-nitrosamines in food samples by high-performance liquid chromatography via combining fluorescent labeling with dispersive liquid-liquid microextraction.

PubMed

Lu, Shuaimin; Wu, Di; Li, Guoliang; Lv, Zhengxian; Gong, Peiwei; Xia, Lian; Sun, Zhiwei; Chen, Guang; Chen, Xuefeng; You, Jinmao; Wu, Yongning

2017-11-01

The intake of N-nitrosamines (NAs) from foodstuffs is considered to be an important influence factor for several cancers. But the rapid and sensitive screening of NAs remains a challenge in the field of food safety. Inspired by that, a sensitive and rapid method was demonstrated for determination of five NAs (Nitrosopyrrolidine, Nitrosodimethylamine, Nitrosodiethylamine, Nitrosodipropylamine and Nitrosodibutylamine) using dispersive liquid-liquid microextraction (DLLME) followed by high-performance liquid chromatography with fluorescence detection (HPLC-FLD). The NAs were firstly denitrosated and labeled by 2-(11H-benzo[a]carbazol-11-yl) ethyl carbonochloridate (BCEC-Cl) and finally enriched by DLLME. Furthermore, the main DLLME conditions were optimized systematically. Under the optimal conditions, satisfactory limits of detection (LODs) were obtained with a range of 0.01-0.07ngg -1 , which were significantly lower than the reported methods. The developed method showed many merits including rapidity, simplicity, high sensitivity and excellent selectivity, which shows a broad prospect in food safety analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Determination of Fusarium toxins in functional vegetable milks applying salting-out-assisted liquid-liquid extraction combined with ultra-high-performance liquid chromatography tandem mass spectrometry.

PubMed

Hamed, Ahmed M; Arroyo-Manzanares, Natalia; García-Campaña, Ana M; Gámiz-Gracia, Laura

2017-11-01

Vegetable milks are considered as functional foods due to their physiological benefits. Although the consumption of these products has significantly increased, they have received little attention in legislation with regard to contaminants. However, they may contain mycotoxins resulting from the use of contaminated raw materials. In this work, ultra-high-performance liquid chromatography tandem mass spectrometry has been proposed for the determination of the most relevant Fusarium toxins (fumonisin B 1 and B 2 , HT-2 and T-2 toxins, zearalenone, deoxynivalenol and fusarenon-X) in different functional beverages based on cereals, legumes and seeds. Sample treatment consisted of a simple salting-out-assisted liquid-liquid extraction with no further clean-up. The method provided limits of quantification between 3.2 and 57.7 µg L -1 , recoveries above 80% and precision with RSD lower than 12%. The method was also applied for studying the occurrence of these mycotoxins in market samples of vegetable functional beverages and deoxynivalenol was found in three oat-based commercial drinks.

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.

Time- and cost-saving apparatus for analytical sample filtration

Treesearch

William R. Kenealy; Joseph C. Destree

2005-01-01

Simple and cost-effective protocols were developed for removing particulates from samples prior to analysis by high performance liquid chromatography and gas chromatography. A filter and vial holder were developed for use with a 96-well filtration plate. The device saves preparation time and costs.

Comprehensive analysis of pharmaceutical products using simultaneous mixed-mode (ion-exchange/reversed-phase) and hydrophilic interaction liquid chromatography.

PubMed

Kazarian, Artaches A; Nesterenko, Pavel N; Soisungnoen, Phimpha; Burakham, Rodjana; Srijaranai, Supalax; Paull, Brett

2014-08-01

Liquid chromatographic assays were developed using a mixed-mode column coupled in sequence with a hydrophilic interaction liquid chromatography column to allow the simultaneous comprehensive analysis of inorganic/organic anions and cations, active pharmaceutical ingredients, and excipients (carbohydrates). The approach utilized dual sample injection and valve-mediated column switching and was based upon a single high-performance liquid chromatography gradient pump. The separation consisted of three distinct sequential separation mechanisms, namely, (i) ion-exchange, (ii) mixed-mode interactions under an applied dual gradient (reversed-phase/ion-exchange), and (iii) hydrophilic interaction chromatography. Upon first injection, the Scherzo SS C18 column (Imtakt) provided resolution of inorganic anions and cations under isocratic conditions, followed by a dual organic/salt gradient to elute active pharmaceutical ingredients and their respective organic counterions and potential degradants. At the top of the mixed-mode gradient (high acetonitrile content), the mobile phase flow was switched to a preconditioned hydrophilic interaction liquid chromatography column, and the standard/sample was reinjected for the separation of hydrophilic carbohydrates, some of which are commonly known excipients in drug formulations. The approach afforded reproducible separation and resolution of up to 23 chemically diverse solutes in a single run. The method was applied to investigate the composition of commercial cough syrups (Robitussin®), allowing resolution and determination of inorganic ions, active pharmaceutical ingredients, excipients, and numerous well-resolved unknown peaks. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quality assessment of crude and processed Arecae semen based on colorimeter and HPLC combined with chemometrics methods.

PubMed

Sun, Meng; Yan, Donghui; Yang, Xiaolu; Xue, Xingyang; Zhou, Sujuan; Liang, Shengwang; Wang, Shumei; Meng, Jiang

2017-05-01

Raw Arecae Semen, the seed of Areca catechu L., as well as Arecae Semen Tostum and Arecae semen carbonisata are traditionally processed by stir-baking for subsequent use in a variety of clinical applications. These three Arecae semen types, important Chinese herbal drugs, have been used in China and other Asian countries for thousands of years. In this study, the sensory technologies of a colorimeter and sensitive validated high-performance liquid chromatography with diode array detection were employed to discriminate raw Arecae semen and its processed drugs. The color parameters of the samples were determined by a colorimeter instrument CR-410. Moreover, the fingerprints of the four alkaloids of arecaidine, guvacine, arecoline and guvacoline were surveyed by high-performance liquid chromatography. Subsequently, Student's t test, the analysis of variance, fingerprint similarity analysis, hierarchical cluster analysis, principal component analysis, factor analysis and Pearson's correlation test were performed for final data analysis. The results obtained demonstrated a significant color change characteristic for components in raw Arecae semen and its processed drugs. Crude and processed Arecae semen could be determined based on colorimetry and high-performance liquid chromatography with a diode array detector coupled with chemometrics methods for a comprehensive quality evaluation. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recent development in liquid chromatography stationary phases for separation of Traditional Chinese Medicine components.

PubMed

Jin, Hongli; Liu, Yanfang; Guo, Zhimou; Wang, Jixia; Zhang, Xiuli; Wang, Chaoran; Liang, Xinmiao

2016-10-25

Traditional Chinese Medicine (TCM) is an ancient medical practice which has been used to prevent and cure diseases for thousands of years. TCMs are frequently multi-component systems with mainly unidentified constituents. The study of the chemical compositions of TCMs remains a hotspot of research. Different strategies have been developed to manage the significant complexity of TCMs, in an attempt to determine their constituents. Reversed-phase liquid chromatography (RPLC) is still the method of choice for the separation of TCMs, but has many problems related to limited selectivity. Recently, enormous efforts have been concentrated on the development of efficient liquid chromatography (LC) methods for TCMs, based on selective stationary phases. This can improve the resolution and peak capacity considerably. In addition, high-efficiency stationary phases have been applied in the analysis of TCMs since the invention of ultra high-performance liquid chromatography (UHPLC). This review describes the advances in LC methods in TCM research from 2010 to date, and focuses on novel stationary phases. Their potential in the separation of TCMs using relevant applications is also demonstrated. Copyright © 2016 Elsevier B.V. All rights reserved.

Simultaneous determination of ascorbic acid and caffeine in commercial soft drinks using reversed-phase ultraperformance liquid chromatography.

PubMed

Turak, Fatma; Güzel, Remziye; Dinç, Erdal

2017-04-01

A new reversed-phase ultraperformance liquid chromatography method with a photodiode array detector was developed for the quantification of ascorbic acid (AA) and caffeine (CAF) in 11 different commercial drinks consisting of one energy drink and 10 ice tea drinks. Separation of the analyzed AA and CAF with an internal standard, caffeic acid, was performed on a Waters BEH C 18 column (100 mm × 2.1 mm, 1.7 μm i.d.), using a mobile phase consisting of acetonitrile and 0.2M H 3 PO 4 (11:89, v/v) with a flow rate of 0.25 mL/min and an injection volume of 1.0 μL. Calibration graphs for AA and CAF were computed from the peak area ratio of AA/internal standard and CAF/internal standard detected at 244.0 nm and 273.6 nm, respectively. The developed reversed-phase ultraperformance liquid chromatography method was validated by analyzing standard addition samples. The proposed reversed-phase ultraperformance liquid chromatography method gave us successful results for the quantitative analysis of commercial drinks containing AA and CAF substances. Copyright © 2016. Published by Elsevier B.V.

21 CFR 862.2250 - Gas liquid chromatography system for clinical use.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Gas liquid chromatography system for clinical use... Instruments § 862.2250 Gas liquid chromatography system for clinical use. (a) Identification. A gas liquid... pressure. The device may include accessories such as columns, gases, column supports, and liquid coating...

21 CFR 862.2250 - Gas liquid chromatography system for clinical use.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Gas liquid chromatography system for clinical use... Instruments § 862.2250 Gas liquid chromatography system for clinical use. (a) Identification. A gas liquid... pressure. The device may include accessories such as columns, gases, column supports, and liquid coating...

21 CFR 862.2250 - Gas liquid chromatography system for clinical use.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Gas liquid chromatography system for clinical use... Instruments § 862.2250 Gas liquid chromatography system for clinical use. (a) Identification. A gas liquid... pressure. The device may include accessories such as columns, gases, column supports, and liquid coating...

21 CFR 862.2250 - Gas liquid chromatography system for clinical use.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Gas liquid chromatography system for clinical use... Instruments § 862.2250 Gas liquid chromatography system for clinical use. (a) Identification. A gas liquid... pressure. The device may include accessories such as columns, gases, column supports, and liquid coating...

21 CFR 862.2250 - Gas liquid chromatography system for clinical use.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Gas liquid chromatography system for clinical use... Instruments § 862.2250 Gas liquid chromatography system for clinical use. (a) Identification. A gas liquid... pressure. The device may include accessories such as columns, gases, column supports, and liquid coating...

Metal-organic frameworks in chromatography.

PubMed

Yusuf, Kareem; Aqel, Ahmad; ALOthman, Zeid

2014-06-27

Metal-organic frameworks (MOFs) emerged approximately two decades ago and are the youngest class of porous materials. Despite their short existence, MOFs are finding applications in a variety of fields because of their outstanding chemical and physical properties. This review article focuses on the applications of MOFs in chromatography, including high-performance liquid chromatography (HPLC), gas chromatography (GC), and other chromatographic techniques. The use of MOFs in chromatography has already had a significant impact; however, the utilisation of MOFs in chromatography is still less common than other applications, and the number of MOF materials explored in chromatography applications is limited. Copyright © 2014 Elsevier B.V. All rights reserved.

Salting-out homogenous extraction followed by ionic liquid/ionic liquid liquid-liquid micro-extraction for determination of sulfonamides in blood by high performance liquid chromatography.

PubMed

Liu, Zhongling; Yu, Wei; Zhang, Hanqi; Gu, Fanbin; Jin, Xiangqun

2016-12-01

Salting-out homogenous extraction followed by ionic liquid/ionic liquid dispersive liquid-liquid micro-extraction system was developed and applied to the extraction of sulfonamides in blood. High-performance liquid chromatography was applied to the determination of the analytes. The blood sample was centrifuged to obtain the serum. After the proteins in the serum were removed in the presence of acetonitrile, ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate, dipotassium hydrogen phosphate, ionic liquid 1-Hexyl-3-methylimidazolium hexafluorophosphate were added into the resulting solution. After the resulting mixture was ultrasonically shaken and centrifuged, the precipitate was separated. The acetonitrile was added in the precipitate and the analytes were extracted into the acetonitrile phase. The parameters affecting the extraction efficiency, such as volume of ionic liquid, amount of dipotassium hydrogen phosphate, volume of dispersant, extraction time and temperature were investigated. The limits of detection of sulfamethizole (STZ), sulfachlorpyridazine (SCP), sulfamethoxazole (SMX) and Sulfisoxazole (SSZ) were 4.78, 3.99, 5.21 and 3.77μgL -1 , respectively. When the present method was applied to the analysis of real blood samples, the recoveries of analytes ranged from 90.0% to 113.0% and relative standard deviations were lower than 7.2%. Copyright © 2016 Elsevier B.V. All rights reserved.

Determination of sulfonamides in butter samples by ionic liquid magnetic bar liquid-phase microextraction high-performance liquid chromatography.

PubMed

Wu, Lijie; Song, Ying; Hu, Mingzhu; Xu, Xu; Zhang, Hanqi; Yu, Aimin; Ma, Qiang; Wang, Ziming

2015-01-01

A novel, simple, and environmentally friendly pretreatment method, ionic liquid magnetic bar liquid-phase microextraction, was developed for the determination of sulfonamides in butter samples by high-performance liquid chromatography. The ionic liquid magnetic bar was prepared by inserting a stainless steel wire into the hollow of a hollow fiber and immobilizing ionic liquid in the micropores of the hollow fiber. In the extraction process, the ionic liquid magnetic bars were used to stir the mixture of sample and extraction solvent and enrich the sulfonamides in the mixture. After extraction, the analyte-adsorbed ionic liquid magnetic bars were readily isolated with a magnet from the extraction system. It is notable that the present method was environmentally friendly since water and only several microliters of ionic liquid were used in the whole extraction process. Several parameters affecting the extraction efficiency were investigated and optimized, including the type of ionic liquid, sample-to-extraction solvent ratio, the number of ionic liquid magnetic bars, extraction temperature, extraction time, salt concentration, stirring speed, pH of the extraction solvent, and desorption conditions. The recoveries were in the range of 73.25-103.85 % and the relative standard deviations were lower than 6.84 %. The experiment results indicated that the present method was effective for the extraction of sulfonamides in high-fat content samples.

Identification of Ginkgo biloba supplements adulteration using high performance thin layer chromatography and ultra high performance liquid chromatography-diode array detector-quadrupole time of flight-mass spectometry

USDA-ARS?s Scientific Manuscript database

Ginkgo biloba is one of the most widely sold herbal supplements and medicines in the world. Its popularity stems to have a positive effect on memory and the circulatory system in clinical studies. As ginkgo popularity increased, non-proprietary extracts were introduced claiming to have similar phyto...

Optimization of Sample Preparation for the Identification and Quantification of Saxitoxin in Proficiency Test Mussel Sample using Liquid Chromatography-Tandem Mass Spectrometry

PubMed Central

Harju, Kirsi; Rapinoja, Marja-Leena; Avondet, Marc-André; Arnold, Werner; Schär, Martin; Burrell, Stephen; Luginbühl, Werner; Vanninen, Paula

2015-01-01

Saxitoxin (STX) and some selected paralytic shellfish poisoning (PSP) analogues in mussel samples were identified and quantified with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Sample extraction and purification methods of mussel sample were optimized for LC-MS/MS analysis. The developed method was applied to the analysis of the homogenized mussel samples in the proficiency test (PT) within the EQuATox project (Establishment of Quality Assurance for the Detection of Biological Toxins of Potential Bioterrorism Risk). Ten laboratories from eight countries participated in the STX PT. Identification of PSP toxins in naturally contaminated mussel samples was performed by comparison of product ion spectra and retention times with those of reference standards. The quantitative results were obtained with LC-MS/MS by spiking reference standards in toxic mussel extracts. The results were within the z-score of ±1 when compared to the results measured with the official AOAC (Association of Official Analytical Chemists) method 2005.06, pre-column oxidation high-performance liquid chromatography with fluorescence detection (HPLC-FLD). PMID:26610567

Development of analyses by high-performance liquid chromatography and liquid chromatography/tandem mass spectrometry of bilberry (Vaccinium myrtilus) anthocyanins in human plasma and urine.

PubMed

Cooke, Darren N; Thomasset, Sarah; Boocock, David J; Schwarz, Michael; Winterhalter, Peter; Steward, William P; Gescher, Andreas J; Marczylo, Timothy H

2006-09-20

Anthocyanins are potent antioxidants that may possess chronic disease preventive properties. Here, rapid, reliable, and reproducible solid-phase extraction, high-performance liquid chromatography (HPLC), and mass spectrometry techniques are described for the isolation, separation, and identification of anthocyanins in human plasma and urine. Recoveries of cyanidin-3-glucoside (C3G) were 91% from water, 71% from plasma, and 81% from urine. Intra- and interday variations for C3G extraction were 9 and 9.1% in plasma and 7.1 and 9.1% in urine and were less than 15% for all anthocyanins from a standardized bilberry extract (mirtoselect). Analysis of mirtoselect by HPLC with UV detection produced spectra with 15 peaks compatible with anthocyanin components found in mirtoselect within a total run time of 15 min. Chromatographic analysis of human urine obtained after an oral dose of mirtoselect yielded 19 anthocyanin peaks. Mass spectrometric analysis employing multiple reaction monitoring suggests the presence of unchanged anthocyanins and anthocyanidin glucuronide metabolites.

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

USDA-ARS?s Scientific Manuscript database

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

Simple Method for Assaying Colistin Methanesulfonate in Plasma and Urine Using High-Performance Liquid Chromatography

PubMed Central

Li, Jian; Milne, Robert W.; Nation, Roger L.; Turnidge, John D.; Coulthard, Kingsley; Valentine, Jason

2002-01-01

A simple and sensitive high-performance liquid chromatographic method is described for the determination of colistimethate sodium in plasma and urine. The accuracy and reproducibility was within 10.1 and 11.2% with rat plasma and urine, respectively. Several commonly coadministered antibacterial agents do not interfere with the assay. PMID:12234867

Determination of molindone enantiomers in human plasma by high-performance liquid chromatography-tandem mass spectrometry using macrocyclic antibiotic chiral stationary phases.

PubMed

Jiang, Hongliang; Li, Yinghe; Pelzer, Mary; Cannon, Michelle J; Randlett, Christopher; Junga, Heiko; Jiang, Xiangyu; Ji, Qin C

2008-05-30

A sensitive and selective bioanalytical assay was developed and validated for the determination of enantiomeric molindone in human plasma using high-performance liquid chromatography-tandem mass spectrometry along with supported liquid extraction procedures. The chiral separation was evaluated and optimized on macrocyclic antibiotic type chiral stationary phases (CSPs) based on teicoplanin aglycone (Chirobiotic TAG) in polar organic, polar ionic, and reversed-phase mode chromatography, respectively. Complete baseline separation was achieved on a Chirobiotic TAG column under isocratic condition in reversed-phase chromatography. The method validation was conducted using a Chirobiotic TAG column (100 mm x 2.1 mm) over the curve range 0.100-100 ng/ml for each molindone enantiomer using 0.0500 ml of plasma sample. The flow rate was 0.8 ml/min and the total run time was 9 min. Supported liquid extraction in a 96-well plate format was used for sample preparation. Parameters including recovery, matrix effect, linearity, sensitivity, specificity, carryover, precision, accuracy, dilution integrity, and stability were evaluated. The intra- and inter-day precision and accuracy of the quality control samples at low, medium, and high concentration levels were RSD

Simultaneous determination of four alkaloids in Lindera aggregata by ultra-high-pressure liquid chromatography-tandem mass spectrometry.

PubMed

Han, Zheng; Zheng, Yunliang; Chen, Na; Luan, Lianjun; Zhou, Changxin; Gan, Lishe; Wu, Yongjiang

2008-11-28

A new separation and quantification method using liquid chromatography under ultra-high-pressure in combination with tandem mass spectrometry (MS/MS) was developed for simultaneous determination of four alkaloids in Lindera aggregata. The analysis was performed on an Acquity UPLC BEH C(18) column (50mmx2.1mm, 1.7microm particle size; Waters, Milford, MA, USA) utilizing a gradient elution profile and a mobile phase consisting of (A) water containing 10mM ammonium acetate adjusted to pH 3 with acetic acid and (B) acetonitrile. An electrospray ionization (ESI)-tandem interface in the positive mode was employed prior to mass spectrometric detection. The calibration curve was linear over the range of 17.1-856ng for boldine, 42.4-2652ng for norboldine, 6.1-304ng for reticuline and 0.5-50ng for linderegatine, respectively. The average recoveries ranged from 99.2 to 101.4% with RSDs< or =2.7%. Then, four L. aggregata samples from different batches were analyzed using the established method. The results indicated that ultra-high-pressure liquid chromatography-tandem mass spectrometry provided improved chromatographic parameters resulting in significantly increased sample throughput including lower solvent consumption and lower limits of quantitation (LOQs) for most of target analytes compared to previous method employing conventional high-performance liquid chromatography (HPLC) separation. So, the established method was validated, sensitive and reliable for the determination of four alkaloids in L. aggregata.

Quality by design: a systematic and rapid liquid chromatography and mass spectrometry method for eprosartan mesylate and its related impurities using a superficially porous particle column.

PubMed

Kalariya, Pradipbhai D; Kumar Talluri, Murali V N; Gaitonde, Vinay D; Devrukhakar, Prashant S; Srinivas, Ragampeta

2014-08-01

The present work describes the systematic development of a robust, precise, and rapid reversed-phase liquid chromatography method for the simultaneous determination of eprosartan mesylate and its six impurities using quality-by-design principles. The method was developed in two phases, screening and optimization. During the screening phase, the most suitable stationary phase, organic modifier, and pH were identified. The optimization was performed for secondary influential parameters--column temperature, gradient time, and flow rate using eight experiments--to examine multifactorial effects of parameters on the critical resolution and generated design space representing the robust region. A verification experiment was performed within the working design space and the model was found to be accurate. This study also describes other operating features of the column packed with superficially porous particles that allow very fast separations at pressures available in most liquid chromatography instruments. Successful chromatographic separation was achieved in less than 7 min using a fused-core C18 (100 mm × 2.1 mm, 2.6 μm) column with linear gradient elution of 10 mM ammonium formate (pH 3.0) and acetonitrile as the mobile phase. The method was validated for specificity, linearity, accuracy, precision, and robustness in compliance with the International Conference on Harmonization Q2 (R1) guidelines. The impurities were identified by liquid chromatography with mass spectrometry. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chiral ligand exchange high-speed countercurrent chromatography: mechanism, application and comparison with conventional liquid chromatography in enantioseparation of aromatic α-hydroxyl acids

PubMed Central

Tong, Shengqiang; Shen, Mangmang; Cheng, Dongping; Ito, Yoichiro; Yan, Jizhong

2014-01-01

This work concentrates on the separation mechanism and application of chiral ligand exchange high-speed countercurrent chromatography (HSCCC) in enantioseparations, and comparison with traditional chiral ligand exchange high performance liquid chromatography (HPLC). The enantioseparation of ten aromatic α-hydroxyl acids were performed by these two chromatographic methods. Results showed that five of the racemates were successfully enantioseparated by HSCCC while only three of the racemates could be enantioseparated by HPLC using a suitable chiral ligand mobile phase additive. For HSCCC, the two-phase solvent system was composed of butanol-water (1:1, v/v), to which N-n-dodecyl-L-proline was added in the organic phase as chiral ligand and cupric acetate was added in the aqueous phase as a transition metal ion. Various operation parameters in HSCCC were optimized by enantioselective liquid-liquid extraction. Based on the results of the present studies the separation mechanism for HSCCC was proposed. For HPLC, the optimized mobile phase composed of aqueous solution containing 6 mmol L−1 L-phenylalanine and 3 mmol L−1 cupric sulfate and methanol was used for enantioseparation. Among three ligands tested on a conventional reverse stationary phase column, only one was found to be effective. In the present studies HSCCC presented unique advantages due to its high versatility of two-phase solvent systems and it could be used as an alternative method for enantioseparations. PMID:25087742

A strategy for identification and structural characterization of compounds from Gardenia jasminoides by integrating macroporous resin column chromatography and liquid chromatography-tandem mass spectrometry combined with ion-mobility spectrometry.

PubMed

Wang, Lu; Liu, Shu; Zhang, Xueju; Xing, Junpeng; Liu, Zhiqiang; Song, Fengrui

2016-06-24

In this paper, an analysis strategy integrating macroporous resin (AB-8) column chromatography and high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) combined with ion mobility spectrometry (IMS) was proposed and applied for identification and structural characterization of compounds from the fruits of Gardenia jasminoides. The extracts of G. jasminoides were separated by AB-8 resin column chromatography combined with reversed phase liquid chromatography (C18 column) and detected by electrospray ionization tandem mass spectrometry. Additionally, ion mobility spectrometry (IMS) was employed as a supplementary separation technique to discover previously undetected isomers from the fruits of G. jasminoides. A total of 71 compounds, including iridoids, flavonoids, triterpenes, monoterpenoids, carotenoids and phenolic acids were identified by the characteristic high resolution mass spectrometry and the ESI-MS/MS fragmentations. In conclusion, the IMS-MS technique achieved the separation of isomers in crocin-3 and crocin-4 according to their acquired mobility drift times differing from classical analysis by mass spectrometry. The proposed strategy can be used as a highly sensitive and efficient procedure for identification and separation isomeric components in extracts of herbal medicines. Copyright © 2016 Elsevier B.V. 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.

Use of high pressure liquid chromatography in the study of liquid lubricant oxidation

NASA Technical Reports Server (NTRS)

Morales, W.

1982-01-01

The general principles of classical liquid chromatography and high-pressure liquid chromatography (HPLC) are reviewed, and their advantages and disadvantages are compared. Several chromatographic techniques are reviewed, and the analysis of a C-ether liquid lubricant by each technique is illustrated. An analysis by size exclusion chromatography of an ester lubricant, which had been degraded using a micro-oxidation apparatus, is illustrated to show how HPLC can be used in the study of high-temperature lubricant degradation.

Rapid resolution liquid chromatography-mass spectrometry and high-performance liquid chromatography-fluorescence detection for metabolism and pharmacokinetic studies of ergosta-4,6,8(14),22-tetraen-3-one.

PubMed

Zhao, Ying-Yong; Qin, Xiang-Yang; Cheng, Xian-Long; Liu, Xue-Ying; Lin, Rui-Chao; Zhang, Yongmin; Li, Xiao-Ye; Sun, Xiao-Li; Sun, Wen-Ji

2010-08-24

Ergosta-4,6,8(14),22-tetraen-3-one (ergone) from many medicinal plants has been demonstrated to possess a variety of pharmacological activities in vivo and in vitro, including cytotoxic, diuretic and immunosuppressive activity. Metabolism and pharmacokinetic studies on rat were conducted for ergone. Rapid resolution liquid chromatography with atmospheric pressure chemical ionization tandem multi-stage mass spectrometry (RRLC-APCI-MS(n)) and high-performance liquid chromatography with fluorescence detection (HPLC-FLD) methods were applied for the identification and quantification of ergone and its metabolite from rat plasma, faeces and urine. A metabolite was identified by RRLC-DAD-APCI-MS(n): 22,23-epoxy-ergosta-4,6,8(14)-triaen-3-one (epoxyergone). The concentrations of the analyte with its metabolites were determined by HPLC-FLD at excitation wavelength of 370 nm and emission wavelength of 485 nm. The samples were deproteinized with methanol after addition of camptothecin as internal standard (IS). The analysis was performed on a Diamonsil C18 column (150 mm x 4.6 mm x 5 microm) with a mobile phase gradient consisting of methanol and water at a flow rate of 1 mL min(-1). The assay was linear over the concentration range of 42-1500, 36-7500 and 42-1500 ng mL(-1) for plasma, faecal homogenate and urine respectively. The absolute recoveries were found to be 97.0+/-1.2%, 98.1+/-0.7% and 96.6+/-1.8% for plasma, faecal homogenate and urine respectively. The intra-day and inter-day relative standard deviations (RSD) were less than 10%. The previous HPLC-MS/MS method is not affordable for most laboratories because of the specialty requirement and high equipment cost. However, the HPLC-FLD method is economic and operating simply for quantitative determination of ergone and its metabolite in rat plasma, faeces and urine. In addition, liquid chromatography coupled with ion trap multi-stage mass spectrometry is becoming a useful technique for ergone metabolite identification. 2010 Elsevier B.V. All rights reserved.

A high-performance liquid chromatography micromethod for the simultaneous determination of vigabatrin and gabapentin in serum.

PubMed

Ratnaraj, N; Patsalos, P N

1998-08-01

A gradient high-performance liquid chromatography micromethod is described for the simultaneous quantitation of vigabatrin and gabapentin in human serum. Chromatography was performed using a 125- x 3-mm ID Hypersil BDS C-18 column with a 3-microm mini-bore, eluted with a gradient system comprised of phosphate buffer (pH 6.5)-acetonitrile-methanol-water at a flow rate of 0.45 ml/minute. The column eluent was monitored on a fluorescence detector using excitation and emission wavelengths of 340 and 440 nm, respectively. The lower limit of quantitation for vigabatrin and for gabapentin was 5 micromol/l, and the within-batch and between-batch coefficients of variation were <5%. No interference from commonly prescribed antiepileptic drugs (carbamazepine and its metabolite carbamazepine epoxide, oxcarbazepine and its metabolite 10-hydroxycarbazepine, ethosuximide, lamotrigine, phenobarbitone, phenytoin, primidone, and valproic acid) was observed; thus, the method can be used to monitor vigabatrin and gabapentin in patients on polytherapy antiepileptic drug regimens.

Lipidomics in triacylglycerol and cholesteryl ester oxidation.

PubMed

Kuksis, Arnis

2007-05-01

Although direct mass spectrometry is capable of identification the major molecular species of lipids in crude total lipid extracts, prior chromatographic isolation is necessary for detection and identification of the minor components. This is especially important for the analysis of the oxolipids, which usually occur in trace amounts in the total lipid extract, and require prior isolation for detailed analysis. Both thin-layer chromatography and adsorption cartridges provide effective means for isolation and enrichment of lipid classes, while gas-liquid chromatography and high performance liquid chromatography with on-line mass spectrometry permit further separation and identification of molecular species. Prior chromatographic resolution is absolutely necessary for the identification of isobaric and chiral molecules, which mass spectrometry/mass spectrometry (MS/MS) cannot distinguish. Both gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry applications may require the preparation of derivatives in order to improve the chromatographic and mass spectrometric properties of the oxolipids which is a small inconvenience for securing analytical reliability. The following chapter reviews the advantages and necessity of combined chromatographic-mass spectrometric approaches to successful identification and quantification of molecular species of oxoacylglycerols and oxocholesteryl esters in in-vitro model studies of lipid peroxidation and in the analyses of oxolipids recovered from tissues.

High-throughput quantification for a drug mixture in rat plasma-a comparison of Ultra Performance liquid chromatography/tandem mass spectrometry with high-performance liquid chromatography/tandem mass spectrometry.

PubMed

Yu, Kate; Little, David; Plumb, Rob; Smith, Brian

2006-01-01

A quantitative Ultra Performance liquid chromatography/tandem mass spectrometry (UPL/MS/MS) protocol was developed for a five-compound mixture in rat plasma. A similar high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) quantification protocol was developed for comparison purposes. Among the five test compounds, three preferred positive electrospray ionization (ESI) and two preferred negative ESI. As a result, both UPLC/MS/MS and HPLC/MS/MS analyses were performed by having the mass spectrometer collecting ESI multiple reaction monitoring (MRM) data in both positive and negative ion modes during a single injection. Peak widths for most standards were 4.8 s for the HPLC analysis and 2.4 s for the UPLC analysis. There were 17 to 20 data points obtained for each of the LC peaks. Compared with the HPLC/MS/MS method, the UPLC/MS/MS method offered 3-fold decrease in retention time, up to 10-fold increase in detected peak height, with 2-fold decrease in peak width. Limits of quantification (LOQs) for both HPLC and UPLC methods were evaluated. For UPLC/MS/MS analysis, a linear range up to four orders of magnitude was obtained with r2 values ranging from 0.991 to 0.998. The LOQs for the five analytes ranged from 0.08 to 9.85 ng/mL. Three levels of quality control (QC) samples were analyzed. For the UPLC/MS/MS protocol, the percent relative standard deviation (RSD%) for low QC (2 ng/mL) ranged from 3.42 to 8.67% (N = 18). The carryover of the UPLC/MS/MS protocol was negligible and the robustness of the UPLC/MS/MS system was evaluated with up to 963 QC injections. Copyright 2006 John Wiley & Sons, Ltd.

A simple high performance liquid chromatography method for analyzing paraquat in soil solution samples.

PubMed

Ouyang, Ying; Mansell, Robert S; Nkedi-Kizza, Peter

2004-01-01

A high performance liquid chromatography (HPLC) method with UV detection was developed to analyze paraquat (1,1'-dimethyl-4,4'-dipyridinium dichloride) herbicide content in soil solution samples. The analytical method was compared with the liquid scintillation counting (LSC) method using 14C-paraquat. Agreement obtained between the two methods was reasonable. However, the detection limit for paraquat analysis was 0.5 mg L(-1) by the HPLC method and 0.05 mg L(-1) by the LSC method. The LSC method was, therefore, 10 times more precise than the HPLC method for solution concentrations less than 1 mg L(-1). In spite of the high detection limit, the UC (nonradioactive) HPLC method provides an inexpensive and environmentally safe means for determining paraquat concentration in soil solution compared with the 14C-LSC method.

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

PubMed

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

1998-07-03

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

Leukotriene B4 catabolism: quantitation of leukotriene B4 and its omega-oxidation products by reversed-phase high-performance liquid chromatography.

PubMed

Shak, S

1987-01-01

LTB4 and its omega-oxidation products may be rapidly, sensitively, and specifically quantitated by the methods of solid-phase extraction and reversed-phase high-performance liquid chromatography (HPLC), which are described in this chapter. Although other techniques, such as radioimmunoassay or gas chromatography-mass spectrometry, may be utilized for quantitative analysis of the lipoxygenase products of arachidonic acid, only the technique of reversed-phase HPLC can quantitate as many as 10 metabolites in a single analysis, without prior derivatization. In this chapter, we also reviewed the chromatographic theory which we utilized in order to optimize reversed-phase HPLC analysis of LTB4 and its omega-oxidation products. With this information and a gradient HPLC system, it is possible for any investigator to develop a powerful assay for the potent inflammatory mediator, LTB4, or for any other lipoxygenase product of arachidonic acid.

GC/MS analysis of high-performance liquid chromatography fractions from Sophora flavescens and Torilis japonica extracts and their in vitro anti-neosporal effects on Neospora caninum.

PubMed

Seo, Hun-Su; Kim, Kyoung Hee; Kim, Dae-Yong; Park, Bong-Kyun; Shin, Nam-Shik; Kim, Jae-Hoon; Youn, Heejeong

2013-01-01

We analyzed alcoholic extracts of herbs possessing anti-neosporal activity against Neospora (N.) caninum. To identify the chemical components of Sophora (S.) flavescens and Torilis (T.) japonica associated with anti-neosporal activity, specific fractions were isolated by high-performance liquid chromatography (HPLC). In vitro activity of the fractions against N. caninum was then assessed. Gas chromatography/ mass spectrometry (GC/MS) was used to identify and quantify specific anti-neosporal molecules in the herbal extracts. Almost all HPLC fractions of S. flavescens and T. japonica had higher levels of anti-neosporal activity compared to the not treated control. Active constituents of the extracts were sophoridane, furosardonin A, and tetraisopropylidene-cyclobutane in S. flavescens; 5,17-β-dihydroxy-de-A-estra-5,7,9,14-tetraene, furanodiene, and 9,12-octadecadienoic acid (Z,Z)-(CAS,1) in T. japonica.

GC/MS analysis of high-performance liquid chromatography fractions from Sophora flavescens and Torilis japonica extracts and their in vitro anti-neosporal effects on Neospora caninum

PubMed Central

Seo, Hun-Su; Kim, Kyoung Hee; Kim, Dae-Yong; Park, Bong-Kyun; Shin, Nam-Shik; Kim, Jae-Hoon

2013-01-01

We analyzed alcoholic extracts of herbs possessing anti-neosporal activity against Neospora (N.) caninum. To identify the chemical components of Sophora (S.) flavescens and Torilis (T.) japonica associated with anti-neosporal activity, specific fractions were isolated by high-performance liquid chromatography (HPLC). In vitro activity of the fractions against N. caninum was then assessed. Gas chromatography/mass spectrometry (GC/MS) was used to identify and quantify specific anti-neosporal molecules in the herbal extracts. Almost all HPLC fractions of S. flavescens and T. japonica had higher levels of anti-neosporal activity compared to the not treated control. Active constituents of the extracts were sophoridane, furosardonin A, and tetraisopropylidene-cyclobutane in S. flavescens; 5,17-β-dihydroxy-de-A-estra-5,7,9,14-tetraene, furanodiene, and 9,12-octadecadienoic acid (Z,Z)-(CAS,1) in T. japonica. PMID:23820198

Nano-liquid chromatography applied to enantiomers separation.

PubMed

Fanali, Salvatore

2017-02-24

This paper presents the state of the art concerning the separation of chiral compounds by means of nano-liquid chromatography (nano-LC). The enantiomers' separation and determination are a subject of fundamental importance in various application fields such as pharmaceutical industry, biomedicine, food, agrochemical etc. Nano-LC is a miniaturized chromatographic technique offering some advantages over conventional ones such as low consumption of mobile phase, sample volume and amount of chiral stationary phase, reduced costs etc. This is reported in the first part of the paper illustrating the features of the nano-LC. In addition, chiral resolution methods are briefly illustrated. Some chiral selectors, used in high-performance liquid chromatography have also been applied in nano-LC including cyclodextrins, glycopeptide antibiotics, modified polysaccharides etc. This is discussed in the second part of the review. Finally some examples of the applications available in literature are reported. Copyright © 2016 Elsevier B.V. All rights reserved.

Chinese Herbal Medicines as Potential Agents for Alleviation of Heat Stress in Poultry

PubMed Central

MD Saadand, Salwani; Idrus, Zulkifli; Diao, Xiao Ping

2017-01-01

Heat stress negatively affects the productivity of chickens in commercial poultry farms in humid tropics. In this study, the concentrations and types of the antioxidant compounds of eight Chinese herbal medicines, which have previously demonstrated promising effects on suppressing heat stress as a mixture, were investigated using reversed-phase High Performance Liquid Chromatography, spectrophotometry, Liquid Chromatography Mass Spectrometry, and Gas-Liquid Chromatography. Our results provided the levels of phenolic compounds, total amounts of sugars, and total unsaturated fatty acids in the herbal extracts. Apart from the detection and quantification of the active ingredients of herbs that have the potential to mitigate heat stress in poultry, results of this study also provide useful data for developing an efficient and accurate formulation of the herbs' mixtures in order to induce positive effects against heat stress in in vivo studies. PMID:29209556

Controlled crosslinking of trimethylolpropane trimethacrylate for preparation of organic monolithic columns for capillary liquid chromatography.

PubMed

Gama, Mariana R; Aggarwal, Pankaj; Lee, Milton L; Bottoli, Carla B G

2017-11-01

Organic monolithic columns based on single crosslinking of trimethylolpropane trimethacrylate (TRIM) monomer were prepared in a single step by living/controlled free-radical polymerization. Full optimization of the preparation, such as using different percentages of TRIM and different amounts of radical promoter as well as various porogen solvents were explored. The resulting monolithic columns were characterized by scanning electronic microscopy and nitrogen sorption for structure morphology studies and surface area measurements, respectively. Using capillary liquid chromatography, 150 μm i.d. columns were applied to separate a mixture of small hydrophobic molecules. The results indicated that column performance is highly sensitive to the type and the amount of porogen solvents used in the polymerization mixture composition. Good resolution factors and methylene selectivity were obtained, indicating the promising potential of this material for capillary liquid chromatography separations. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Contemporary Carbon Content of Bis (2-ethylhexyl) Phthalate in Butter

PubMed Central

Tong, T.; Ondov, J. M.; Buchholz, B. A.; VanDerveer, M. C.

2016-01-01

The fraction of naturally produced Bis (2-ethylhexyl) phthalate (DEHP), a ubiquitous plasticizer known to contaminate packaged foods, was determined for each of five 1.10 kg samples of unsalted market butter by accelerator mass spectrometry (AMS). After extraction and concentration enrichment with liquid-liquid extraction, flash column chromatography, and preparative-scale high performance liquid chromatography, each sample provided ≈250 µg extracts of DEHP with carbon purity ranging from 92.5±1.2% (n=3, 1σ) to 97.1±0.8% (n=3, 1σ) as measured with gas chromatography mass spectrometry (GC-MS). After corrections for method blank DEHP, co-eluting compounds, and unidentified carbon, the mean fraction of naturally produced DEHP in butter was determined to be 0.16±0.12 (n=5, 1σ). To our knowledge, this is the first report of the contemporary fraction of DEHP isolated from market butter in the U.S. PMID:26213077

Development of a gas chromatography method for the determination of isotretinoin and its degradation products in pharmaceuticals.

PubMed

Lima, Eliana Martins; Diniz, Danielle G Almeida; Antoniosi-Filho, Nelson R

2005-07-15

This paper describes the development of a gas chromatography (GC) method used for the assay of isotretinoin in its isolated form and in pharmaceutical formulations. Isotretinoin soft and hard gelatin capsules were prepared with various excipients. The performance of the proposed gas chromatography method was compared to that of traditional high performance liquid chromatography (HPLC) systems for this substance, and the GC parameters were established based on several preliminary tests, including thermal analysis of isotretinoin. Results showed that gas chromatography-flame ionization detector (GC-FID) exhibited a separation efficiency superior to that of HPLC, particularly for separating isotretinoin degradation products. This method was proven to be effectively applicable to stability evaluation assays of isotretinoin and isotretinoin based pharmaceuticals.

On-line hyphenation of centrifugal partition chromatography and high pressure liquid chromatography for the fractionation of flavonoids from Hippophaë rhamnoides L. berries.

PubMed

Michel, Thomas; Destandau, Emilie; Elfakir, Claire

2011-09-09

Centrifugal Partition Chromatography (CPC), a liquid-liquid preparative chromatography using two immiscible solvent systems, benefits from numerous advantages for the separation or purification of synthetic or natural products. This study presents the on-line hyphenation of CPC-Evaporative Light Scattering Detector (CPC-ELSD) with High Performance Liquid Chromatography-UV (HPLC-UV) for the fractionation of flavonols from a solvent-free microwave extract of sea buckthorn (Hippophaë rhamnoides L., Elaeagnaceae) berries. An Arizona G system was used for the fractionation of flavonoids by CPC and a fused core Halo C18 column allowed the on-line analyses of collected fractions by HPLC. The on-line CPC/HPLC procedure allowed the simultaneous fractionation step at preparative scale combined with the HPLC analyses which provide direct fingerprint of collected fractions. Thus the crude extract was simplified and immediate information on the composition of fractions could be obtained. Furthermore, this methodology reduced the time of post-fractionation steps and facilitated identification of main molecules by Mass Spectrometry (MS). Rutin, isorhamnetin-3-O-rutinoside, isorhamnetin-3-O-glucoside, quercetin-3-O-glucoside, isorhamnetin-rhamnoside, quercetin and isorhamnetin were identified. CPC-ELSD/HPLC-UV could be considered as a high-throughput technique for the guided fractionation of bioactive natural products from complex crude extracts. Copyright © 2011 Elsevier B.V. All rights reserved.

Simultaneous qualitative and quantitative determination of phenolic compounds in Aloe barbadensis Mill by liquid chromatography-mass spectrometry-ion trap-time-of-flight and high performance liquid chromatography-diode array detector.

PubMed

Wu, Xiaofang; Ding, Wenjing; Zhong, Jiasheng; Wan, Jinzhi; Xie, Zhiyong

2013-06-01

An effective and comprehensive method was developed for the simultaneous analysis of phenolic compounds in the dried exudate of Aloe barbadensis Mill by liquid chromatography-mass spectrometry-ion trap-time-of-flight (LCMS-IT-TOF) and high performance liquid chromatography-diode array detector (HPLC-DAD). Qualitative analysis of all the compounds presented in A. barbadensis Mill was performed on LCMS-IT-TOF, and the diagnostic fragmentation patterns of different types of phenolic compounds (chromones, phenyl pyrones, naphthalene derivative, anthrones and anthraquinones) were discussed on the basis of ESI-IT-TOF MS of components in A. barbadensis Mill and eleven authentic standards. Under the optimal HPLC-DAD chromatographic conditions, quantification of 11 typical phenolic compounds in 15 batches of A. barbadensis Mill was achieved on an Agilent TC-C18 column using gradient elution with a solvent system of methanol and water at a flow rate of 1.0mLmin(-1) and detected at 230nm. All calibration curves exhibited good linear relationship (r(2)>0.9991). The relative standard deviation values for intraday precision were less than 2% with accuracies between 98.21% and 104.57%. The recoveries of the eleven analytes ranged from 97.53 to 105.00% with RSDs less than 2%. This is the first simultaneous characterization and quantitative determination of multiple phenolic compounds in A. barbadensis Mill from locally grown cultivars in China by LCMS-IT-TOF and HPLC-DAD, which can be applied to standardize the quality of A. barbadensis Mill and the future design of nutraceutical and cosmetic preparations. Copyright © 2013 Elsevier B.V. All rights reserved.

Determination of efavirenz in human dried blood spots by reversed-phase high-performance liquid chromatography with UV detection.

PubMed

Hoffman, Justin T; Rossi, Steven S; Espina-Quinto, Rowena; Letendre, Scott; Capparelli, Edmund V

2013-04-01

Previously published methods for determination of efavirenz (EFV) in human dried blood spots (DBS) use costly and complex liquid chromatography/mass spectrometry. We describe the validation and evaluation of a simple and inexpensive high-performance liquid chromatography method for EFV quantification in human DBS and dried plasma spots (DPS), using ultraviolet detection appropriate for resource-limited settings. One hundred microliters of heparinized whole blood or plasma were spotted onto blood collection cards, dried, punched, and eluted. Eluates are injected onto a C-18 reversed phase high-performance liquid chromatography column. EFV is separated isocratically using a potassium phosphate and acetonitrile mobile phase. Ultraviolet detection is at 245 nm. Quantitation is by use of external calibration standards. Following validation, the method was evaluated using whole blood and plasma from HIV-positive patients undergoing EFV therapy. Mean recovery of drug from DBS is 91.5%. The method is linear over the validated concentration range of 0.3125-20.0 μg/mL. A good correlation (Spearman r = 0.96) between paired plasma and DBS EFV concentrations from the clinical samples was observed, and hematocrit level was not found to be a significant determinant of the EFV DBS level. The mean observed C DBS/C plasma ratio was 0.68. A good correlation (Spearman r = 0.96) between paired plasma and DPS EFV concentrations from the clinical samples was observed. The mean percent deviation of DPS samples from plasma samples is 1.68%. Dried whole blood spot or dried plasma spot sampling is well suited for monitoring EFV therapy in resource-limited settings, particularly when high sensitivity is not essential.

Simultaneous detection of six urinary pteridines and creatinine by high-performance liquid chromatography-tandem mass spectrometry for clinical breast cancer detection.

PubMed

Burton, Casey; Shi, Honglan; Ma, Yinfa

2013-11-19

Recent preliminary studies have implicated urinary pteridines as candidate biomarkers in a growing number of malignancies including breast cancer. While the developments of capillary electrophoresis-laser induced fluorescence (CE-LIF), high performance liquid chromatography (HPLC), and liquid chromatography-mass spectroscopy (LC-MS) pteridine urinalyses among others have helped to enable these findings, limitations including poor pteridine specificity, asynchronous or nonexistent renal dilution normalization, and a lack of information regarding adduct formation in mass spectrometry techniques utilizing electrospray ionization (ESI) have prevented application of these techniques to a larger clinical setting. In this study, a simple, rapid, specific, and sensitive high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method has been developed and optimized for simultaneous detection of six pteridines previously implicated in breast cancer and creatinine as a renal dilution factor in urine. In addition, this study reports cationic adduct formation of urinary pteridines under ESI-positive ionization for the first time. This newly developed technique separates and detects the following six urinary pteridines: 6-biopterin, 6-hydroxymethylpterin, d-neopterin, pterin, isoxanthopterin, and xanthopterin, as well as creatinine. The method detection limit for the pteridines is between 0.025 and 0.5 μg/L, and for creatinine, it is 0.15 μg/L. The method was also validated by spiked recoveries (81-105%), reproducibility (RSD: 1-6%), and application to 25 real urine samples from breast cancer positive and negative samples through a double-blind study. The proposed technique was finally compared directly with a previously reported CE-LIF technique, concluding that additional or alternative renal dilution factors are needed for proper investigation of urinary pteridines as breast cancer biomarkers.

Investigation of the persistence of nerve agent degradation analytes on surfaces through wipe sampling and detection with ultrahigh performance liquid chromatography-tandem mass spectrometry.

PubMed

Willison, Stuart A

2015-01-20

The persistence of chemical warfare nerve agent degradation analytes on surfaces is important, from indicating the presence of nerve agent on a surface to guiding environmental restoration of a site after a release. Persistence was investigated for several chemical warfare nerve agent degradation analytes on indoor surfaces and presents an approach for wipe sampling of surfaces, followed by wipe extraction and liquid chromatography-tandem mass spectrometry detection. Commercially available wipe materials were investigated to determine optimal wipe recoveries. Tested surfaces included porous/permeable (vinyl tile, painted drywall, and wood) and largely nonporous/impermeable (laminate, galvanized steel, and glass) surfaces. Wipe extracts were analyzed by ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). UPLC provides a separation of targeted degradation analytes in addition to being nearly four times faster than high-performance liquid chromatography, allowing for greater throughput after a large-scale contamination incident and subsequent remediation events. Percent recoveries from nonporous/impermeable surfaces were 60-103% for isopropyl methylphosphonate (IMPA), GB degradate; 61-91% for ethyl methylphosphonate (EMPA), VX degradate; and 60-98% for pinacolyl methylphosphonate (PMPA), GD degradate. Recovery efficiencies for methyl phosphonate (MPA), nerve agent degradate, and ethylhydrogen dimethylphosphonate (EHDMAP), GA degradate, were lower, perhaps due to matrix effects. Diisopropyl methylphosphonate, GB impurity, was not recovered from surfaces. The resulting detection limits for wipe extracts were 0.065 ng/cm(2) for IMPA, 0.079 ng/cm(2) for MPA, 0.040 ng/cm(2) for EMPA, 0.078 ng/cm(2) for EHDMAP, and 0.013 ng/cm(2) for PMPA. The data indicate that laboratories may hold wipe samples for up to 30 days prior to analysis. Target analytes were observed to persist on surfaces for at least 6 weeks.

On the use of ionic liquids as mobile phase additives in high-performance liquid chromatography. A review.

PubMed

García-Alvarez-Coque, M C; Ruiz-Angel, M J; Berthod, A; Carda-Broch, S

2015-07-09

The popularity of ionic liquids (ILs) has grown during the last decades in several analytical separation techniques. Consequently, the number of reports devoted to the applications of ILs is still increasing. This review is focused on the use of ILs (mainly imidazolium-based associated to chloride and tetrafluoroborate) as mobile phase additives in high-performance liquid chromatography (HPLC). In this approach, ILs just function as salts, but keep several kinds of intermolecular interactions, which are useful for chromatographic separations. Both cation and anion can be adsorbed on the stationary phase, creating a bilayer. This gives rise to hydrophobic, electrostatic and other specific interactions with the stationary phase and solutes, which modify the retention behaviour and peak shape. This review updates the advances in this field, with emphasis on topics not always deeply considered in the literature, such as the mechanisms of retention, the estimation of the suppressing potency of silanols, modelling and optimisation of the chromatographic performance, and the comparison with other additives traditionally used to avoid the silanol problem. Copyright © 2015 Elsevier B.V. All rights reserved.

Ocfentanil overdose fatality in the recreational drug scene.

PubMed

Coopman, Vera; Cordonnier, Jan; De Leeuw, Marc; Cirimele, Vincent

2016-09-01

This paper describes the first reported death involving ocfentanil, a potent synthetic opioid and structure analogue of fentanyl abused as a new psychoactive substance in the recreational drug scene. A 17-year-old man with a history of illegal substance abuse was found dead in his home after snorting a brown powder purchased over the internet with bitcoins. Acetaminophen, caffeine and ocfentanil were identified in the powder by gas chromatography mass spectrometry and reversed-phase liquid chromatography with diode array detector. Quantitation of ocfentanil in biological samples was performed using a target analysis based on liquid-liquid extraction and ultra performance liquid chromatography tandem mass spectrometry. In the femoral blood taken at the external body examination, the following concentrations were measured: ocfentanil 15.3μg/L, acetaminophen 45mg/L and caffeine 0.23mg/L. Tissues sampled at autopsy were analyzed to study the distribution of ocfentanil. The comprehensive systematic toxicological analysis on the post-mortem blood and tissue samples was negative for other compounds. Based on circumstantial evidence, autopsy findings and the results of the toxicological analysis, the medical examiner concluded that the cause of death was an acute intoxication with ocfentanil. The manner of death was assumed to be accidental after snorting the powder. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

2-Naphthalenthiol derivatization followed by dispersive liquid-liquid microextraction as an efficient and sensitive method for determination of acrylamide in bread and biscuit samples using high-performance liquid chromatography.

PubMed

Faraji, Mohammad; Hamdamali, Mohammadrezza; Aryanasab, Fezzeh; Shabanian, Meisam

2018-07-13

In this research, an ultrasonic-assisted extraction followed by 2-naphthalenthiol derivatization and dispersive liquid-liquid microextraction of acrylamide (AA) was developed as simple and sensitive sample preparation method for AA in bread and biscuit samples using high performance liquid chromatography. Influence of derivatization and microextraction parameters were evaluated and optimized. Results showed that the derivatization of AA leads to improve its hydrophobicity and chromatographic behavior. Under optimum conditions of derivatization and microextraction, the method yielded a linear calibration curve ranging from 10 to 1000 μg L -1 with a determination coefficient (R 2 ) of 0.9987. Limit of detection (LOD) and limit of quantification (LOQ) were 3.0 and 9.0 μg L -1 , respectively. Intra-day (n = 6) and inter-day (n = 3) precisions based on relative standard deviation percent (RSD%) for extraction and determination of AA at 50 and 500 μg L -1 levels were less than 9.0%. Finally, the performance of proposed method was investigated for determination of AA in some bread and biscuit samples, and satisfactory results were obtained (relative recovery ≥ 90%). Copyright © 2018. Published by Elsevier B.V.

Identification of kinetin and kinetin riboside in coconut (Cocos nucifera L.) water using a combined approach of liquid chromatography-tandem mass spectrometry, high performance liquid chromatography and capillary electrophoresis.

PubMed

Ge, Liya; Yong, Jean Wan Hong; Goh, Ngoh Khang; Chia, Lian Sai; Tan, Swee Ngin; Ong, Eng Shi

2005-12-27

Kinetin (free base and riboside), which was assumed by many scientists to be a synthetic cytokinin plant growth hormone, has been detected for the first time in the endosperm liquid of fresh young coconut fruits ("coconut water"). To facilitate the study, we developed a sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the identification and quantification of kinetin and kinetin riboside in purified coconut water extract sample. Following a solid-phase extraction of cytokinins in coconut water using C18 columns, the samples were further purified by Oasis MCX columns and analyzed by LC-MS/MS for kinetin and kinetin riboside. Detection by mass spectrometry was carried out using selected reaction monitoring (SRM) mode, by identifying the putative kinetin and kinetin riboside based on their characteristic fragments. Based on a signal-to-noise ratio of 3, the limits of detection in SRM mode were 0.02 microM and 0.005 microM for kinetin and kinetin riboside, respectively. Furthermore, optimal conditions for a baseline chromatographic separation of 18 cytokinin standards by high performance liquid chromatography (HPLC) were developed. The HPLC method had been employed for the confirmation and further fractionation of kinetin in coconut water extracts. The confirmation and fractionation of kinetin riboside was carried out using a further modified HPLC program due to the presence of other interfering material(s) in the sample matrix. Finally, fractions of putative kinetin and kinetin riboside collected from HPLC eluate of coconut water sample were further authenticated by independent capillary zone electrophoresis (CZE) experiment.

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.

Column Liquid Chromatography.

ERIC Educational Resources Information Center

Majors, Ronald E.; And Others

1984-01-01

Reviews literature covering developments of column liquid chromatography during 1982-83. Areas considered include: books and reviews; general theory; columns; instrumentation; detectors; automation and data handling; multidimensional chromatographic and column switching techniques; liquid-solid chromatography; normal bonded-phase, reversed-phase,…

Analysis of legal high materials by ultra-performance liquid chromatography with time of flight mass spectrometry as part of a toxicology vigilance system: what are the most popular novel psychoactive substances in the UK?

PubMed

Ford, Loretta T; Berg, Jonathan D

2017-03-01

Introduction Legal highs also known as novel psychoactive substances mimic the effects of classic drugs of abuse. Challenges to developing screening services for novel psychoactive substances include identifying which novel psychoactive substances are available to target. Using new techniques such as exact mass time of flight can help identify common novel psychoactive substances to target for screening patient samples by routine methods such as tandem mass spectrometry. We demonstrate this strategy working in our own clinical toxicology laboratory after qualitative analysis of 98 suspect materials for novel psychoactive substances by ultra-performance liquid chromatography with time of flight mass spectrometry. Results From July 2014 to July 2015 we received 98 requests to test a range of different suspect materials for novel psychoactive substances including herbs, tobacco, liquids, pills and powders. Overall, 87% of the suspect materials tested positive for novel psychoactive substances, and 15% for controlled drugs. Three common novel psychoactive substances were present in 74% of the suspect materials: methiopropamine, a methamphetamine analogue; ethylphenidate, a cocaine mimic; and the third generation synthetic cannabinoid 5F-AKB-48. For the 55 branded products we tested only 24% of the stated contents matched exactly the compounds we detected. Conclusion Testing suspect materials using ultra-performance liquid chromatography with time of flight mass spectrometry has identified three common novel psychoactive substances in use in the UK, simplifying the development of a relevant novel psychoactive substances screening service to our population. By incorporating this into our routine liquid chromatography tandem mass spectrometry drugs of abuse screen, then offers a clinically relevant novel psychoactive substances service to our users. This strategy ensures our clinical toxicology service continues to remain effective to meet the challenges of the changing drug use in the UK.

Derivatization of amino acids with N,N-dimethyl-2,4-dinitro-5-fluorobenzylamine for liquid chromatography/electrospray ionization mass spectrometry.

PubMed

Liu, Zhongfa; Minkler, Paul E; Lin, De; Sayre, Lawrence M

2004-01-01

Derivatization, separation and identification of amino acids with a novel compound, N,N-dimethyl-2,4-dinitro-5-fluorobenzylamine (DMDNFB), using high-performance liquid chromatography/electrospray ionization mass spectrometry (HPLC/ESI-MS) was demonstrated. Compared to derivatization with 2,4-dinitrofluorobenzene (DNFB), DMDNFB-derivatized amino acids and dipeptides exhibit much larger ion current signals in the commonly used ESI positive mode, which was attributed to the introduction of the N,N-dimethylaminomethyl protonatable site. Copyright 2004 John Wiley & Sons, Ltd.

[The pharmacokinetics of the dipeptide analog of piracetam with nootropic activity GVS-111 and of its basic metabolites].

PubMed

Boĭko, S S; Zherdev, V P; Dvorianinov, A A; Gudasheva, T A; Ostrovskaia, R U; Voronina, T A; Rozantsev, G G; Seredenin, S B

1997-01-01

The pharmacokinetics of a new nootropic dipeptide analog of piracetam-N-phenylacetyl-L-prolylglycine (GWS-111) and its main metabolites were studied in rats by means of high performance liquid chromatography and gas-liquid chromatography. The compound under study showed a greater resistance to an enzymatic effect than natural neuropeptides. In addition to an unchanged compound three of its metabolites were found in the blood plasma of the rats. One of them, cyclo-Pro-Gly was an active metabolite of GWS-111.

Separation and identification of corticosterone metabolites by liquid chromatography--electrospray ionization mass spectrometry.

PubMed

Miksík, I; Vylitová, M; Pácha, J; Deyl, Z

1999-04-16

High-performance liquid chromatography coupled to atmospheric pressure ionization-electrospray ionization mass spectrometry (API-ESI-MS) was investigated for the analysis of corticosterone metabolites; their characterization was obtained by combining the separation on Zorbax Eclipse XDB C18 column (eluted with a methanol-water-acetic acid gradient) with identification using positive ion mode API-ESI-MS and selected ion analysis. The applicability of this method was verified by monitoring the activity of steroid converting enzymes (20beta-hydroxysteroid dehydrogenase and 11beta-hydroxysteroid dehydrogenase) in avian intestines.

Denaturing high-performance liquid chromatography for mutation detection and genotyping.

PubMed

Fackenthal, Donna Lee; Chen, Pei Xian; Howe, Ted; Das, Soma

2013-01-01

Denaturing high-performance liquid chromatography (DHPLC) is an accurate and efficient screening technique used for detecting DNA sequence changes by heteroduplex analysis. It can also be used for genotyping of single nucleotide polymorphisms (SNPs). The high sensitivity of DHPLC has made this technique one of the most reliable approaches to mutation analysis and, therefore, used in various areas of genetics, both in the research and clinical arena. This chapter describes the methods used for mutation detection analysis and the genotyping of SNPs by DHPLC on the WAVE™ system from Transgenomic Inc. ("WAVE" and "DNASep" are registered trademarks, and "Navigator" is a trademark, of Transgenomic, used with permission. All other trademarks are property of the respective owners).

Determination of sulfates and glucuronides of endogenic steroids in biofluids by high-performance liquid chromatography/orbitrap mass spectrometry

NASA Astrophysics Data System (ADS)

Semenistaya, E. N.; Virus, E. D.; Rodchenkov, G. M.

2009-04-01

the possibility of selective determination of testosterone and epitestosterone glucuronides in urine by high-performance liquid chromatography/high-resolution mass spectrometry using solid phase microextraction on a meps cartridge was studied. the effect of the biological matrix on the spectra of conjugated steroids can be taken into account by using the spectra of conjugates recorded for urine samples after hydrolysis as reference spectra. the conditions of fragmentation in the ion source were optimized for separate analytes. this method was used for analyzing real samples with different testosterone/epitestosterone ratios. variations in conjugate contents and qualitative changes in the steroid profile of endogenic compounds were observed.

Simultaneous determination of azathioprine and 6-mercaptopurine in serum by reversed-phase high-performance liquid chromatography.

PubMed

Tsutsumi, K; Otsuki, Y; Kinoshita, T

1982-09-10

The simultaneous determination of azathioprine and its metabolite 6-mercaptopurine in serum by reversed-phase high-performance liquid chromatography is described. 6-Mercaptopurine was converted to a derivative, 6-mercaptopurine-N-ethylmaleimide, which is stable against autoxidation, on reaction with N-ethylmaleimide. Since the N-ethylmaleimide derivative was more hydrophobic than the parent compound, it could be extracted into ethyl acetate together with azathioprine and the derivative was retained on the reversed-phase column better than 6-mercaptopurine. In addition, 6-mercaptopurine-N-ethylmaleimide absorbed at the same wavelength (280 nm) as azathioprine. Consequently, this derivatization procedure enabled the simultaneous extraction, separation, and detection of these compounds.

Simultaneous separation by reversed-phase high-performance liquid chromatography and mass spectral identification of anthocyanins and flavonols in Shiraz grape skin.

PubMed

Downey, Mark O; Rochfort, Simone

2008-08-01

A limitation of large-scale viticultural trials is the time and cost of comprehensive compositional analysis of the fruit by high-performance liquid chromatography (HPLC). In addition, separate methods have generally been required to identify and quantify different classes of metabolites. To address these shortcomings a reversed-phase HPLC method was developed to simultaneously separate the anthocyanins and flavonols present in grape skins. The method employs a methanol and water gradient acidified with 10% formic acid with a run-time of 48 min including re-equilibration. Identity of anthocyanins and flavonols in Shiraz (Vitis vinifera L.) skin was confirmed by mass spectral analysis.

High-performance liquid chromatography purification of homogenous-length RNA produced by trans cleavage with a hammerhead ribozyme.

PubMed Central

Shields, T P; Mollova, E; Ste Marie, L; Hansen, M R; Pardi, A

1999-01-01

An improved method is presented for the preparation of milligram quantities of homogenous-length RNAs suitable for nuclear magnetic resonance or X-ray crystallographic structural studies. Heterogeneous-length RNA transcripts are processed with a hammerhead ribozyme to yield homogenous-length products that are then readily purified by anion exchange high-performance liquid chromatography. This procedure eliminates the need for denaturing polyacrylamide gel electrophoresis, which is the most laborious step in the standard procedure for large-scale production of RNA by in vitro transcription. The hammerhead processing of the heterogeneous-length RNA transcripts also substantially improves the overall yield and purity of the desired RNA product. PMID:10496226

Novel devices for solvent delivery and temperature programming designed for capillary liquid chromatography.

PubMed

Coutinho, Lincoln Figueira Marins; Nazario, Carlos Eduardo Domingues; Monteiro, Alessandra Maffei; Lanças, Fernando Mauro

2014-08-01

Analyses in chromatographic systems able to save mobile and stationary phases without reducing efficiency and resolution are of current interest. These advantages regarding savings have challenged us to develop a system dedicated to miniaturized liquid chromatography. This paper reports on the development of a high-pressure syringe-type pump, an oven able to perform isothermal and temperature programming and a software program to control these chromatographic devices. The experimental results show that the miniaturized system can generate reproducible and accurate temperature and flow rate. The system was applied to the separation of statins and tetracylines and showed excellent performance. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of carbonyl compounds generated from the E-cigarette using coupled silica cartridges impregnated with hydroquinone and 2,4-dinitrophenylhydrazine, followed by high-performance liquid chromatography.

PubMed

Uchiyama, Shigehisa; Ohta, Kazushi; Inaba, Yohei; Kunugita, Naoki

2013-01-01

Carbonyl compounds in E-cigarette smoke mist were measured using coupled silica cartridges impregnated with hydroquinone and 2,4-dinitrophenylhydrazine, followed by high-performance liquid chromatography. A total of 363 E-cigarettes (13 brands) were examined. Four of the 13 E-cigarette brands did not generate any carbonyl compounds, while the other nine E-cigarette brands generated various carbonyl compounds. However, the carbonyl concentrations of the E-cigarette products did not show typical distributions, and the mean values were largely different from the median values. It was elucidated that E-cigarettes incidentally generate high concentrations of carbonyl compounds.

Determination of alpha-hydroxy acids in cosmetic products by high-performance liquid chromatography with a narrow-bore column.

PubMed

Nicoletti, I; Corradini, C; Cogliandro, E; Cavazza, A

1999-08-01

This paper reports the results of a study carried out to develop a simple, rapid and sensitive method for the separation, identification and quantitative measurement of alpha-hydroxy acids in commercial cosmetics using high-performance liquid chromatography (HPLC). This method is successfully applied to the simultaneous identification and quantitative determination of glycolic, lactic, malic, tartaric and citric acids employing a reversed phase narrow-bore column under isocratic condition and UV detection. The method is validated by determining the precision of replicate analyses and accuracy by analyzing samples with and without adding know amount of the alpha-hydroxy acids. The procedure is suitable for routine analyses of commercial cosmetics.

[Determination of glycyrrhizinic acid in biotransformation system by reversed-phase high performance liquid chromatography].

PubMed

Li, Hui; Lu, Dingqiang; Liu, Weimin

2004-05-01

A method for determining glycyrrhizinic acid in the biotransformation system by reversed-phase high performance liquid chromatography (RP-HPLC) was developed. The HPLC conditions were as follows: Hypersil C18 column (4.6 mm i.d. x 250 mm, 5 microm) with a mixture of methanol-water-acetic acid (70:30:1, v/v) as the mobile phase; flow rate at 1.0 mL/min; and UV detection at 254 nm. The linear range of glycyrrhizinic acid was 0.2-20 microg. The recoveries were 98%-103% with relative standard deviations between 0.16% and 1.58% (n = 3). The method is simple, rapid and accurate for determining glycyrrhizinic acid.

Determination of virginiamycin M1 residue in tissues of swine and chicken by ultra-performance liquid chromatography tandem mass spectrometry.

PubMed

Wang, Xiaoyang; Wang, Mi; Zhang, Keyu; Hou, Ting; Zhang, Lifang; Fei, Chenzong; Xue, Feiqun; Hang, Taijun

2018-06-01

A reliable UPLC-MS/MS method with high sensitivity was developed and validated for the determination of virginiamycin M1 in muscle, fat, liver, and kidney samples of chicken and swine. Analytes were extracted using acetonitrile and extracts were defatted by N-hexane. Chromatographic separation was performed on a BEH C18 liquid chromatography column. The analytes were then detected using triplequadrupole mass spectrometry in positive electrospray ionization and multiple reaction monitoring mode. Calibration plots were constructed using standard working solutions and showed good linearity. Limits of quantification ranged from 2 to 60 ng mL -1 . Copyright © 2018 Elsevier Ltd. All rights reserved.

Nano-particle modified stationary phases for high-performance liquid chromatography.

PubMed

Nesterenko, Ekaterina P; Nesterenko, Pavel N; Connolly, Damian; He, Xiaoyun; Floris, Patrick; Duffy, Emer; Paull, Brett

2013-08-07

This review covers the latest developments and applications of nano-materials in stationary phase development for various modes of high-performance liquid chromatography. Specific attention is placed upon the development of new composite phases, including the synthetic and immobilisation strategies used, to produce either encapsulated nano-particles, or surface attached nano-particles, layers, coatings and other structures. The resultant chromatographic applications, where applicable, are discussed with comment upon enhanced selectivity and/or efficiency of the nano-particle modified phases, where such effects have been identified. In the main this review covers developments over the past five years and is structured according to the nature of the nano-particles themselves, including carbonaceous, metallic, inorganic, and organopolymer based materials.

Consequences of transition from liquid chromatography to supercritical fluid chromatography on the overall performance of a chiral zwitterionic ion-exchanger.

PubMed

Wolrab, Denise; Frühauf, Peter; Gerner, Christopher; Kohout, Michal; Lindner, Wolfgang

2017-09-29

Major differences in the chromatographic performance of a zwitterion ion-exchange type (ZWIX) chiral stationary phase (CSP) in supercritical fluid chromatography (SFC) and high-performance liquid chromatography (HPLC) have been observed. To explain these differences, transition from HPLC to SFC conditions has been performed. The amount of a protic organic modifier in supercritical carbon dioxide (scCO 2 ) was stepwise increased and the effect of this change studied using acidic, basic and ampholytic analytes. At the same time, the effect of various basic additives to the mobile phase and transient acidic buffer species, formed by the reaction of scCO 2 with the organic modifier and additives, was assessed. Evidence is provided that a transient acid together with the intrinsic counter-ions present in the ZWIX selector structure drive the elution of analytes even when no buffer is employed. We show that the tested analytes can be enantioseparated under both SFC and HPLC conditions; the best conditions for the resolution of ampholytes are in the so-called enhanced-fluidity mobile phase region. As a consequence, subcritical fluid and enhanced-fluidity mobile phase regions seem to be chromatographic modes with a high potential for operating ZWIX CSPs. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparison of high-performance liquid chromatography and supercritical fluid chromatography using evaporative light scattering detection for the determination of plasticizers in medical devices.

PubMed

Lecoeur, Marie; Decaudin, Bertrand; Guillotin, Yoann; Sautou, Valérie; Vaccher, Claude

2015-10-23

Recently, interest in supercritical fluid chromatography (SFC) has increased due to its high throughput and the development of new system improving chromatographic performances. However, most papers dealt with fundamental studies and chiral applications and only few works described validation process of SFC method. Likewise, evaporative light scattering detection (ELSD) has been widely employed in liquid chromatography but only a few recent works presented its quantitative performances hyphenated with SFC apparatus. The present paper discusses about the quantitative performances of SFC-ELSD compared to HPLC-ELSD, for the determination of plasticizers (ATBC, DEHA, DEHT and TOTM) in PVC tubing used as medical devices. After the development of HPLC-ELSD, both methods were evaluated based on the total error approach using accuracy profile. The results show that HPLC-ELSD was more precise than SFC-ELSD but lower limits of quantitation were obtained by SFC. Hence, HPLC was validated in the ± 10% acceptance limits whereas SFC lacks of accuracy to quantify plasticizers. Finally, both methods were used to determine the composition of plasticized-PVC medical devices. Results demonstrated that SFC and HPLC both hyphenated with ELSD provided similar results. Copyright © 2015 Elsevier B.V. All rights reserved.

Simultaneous determination of nicotine and cotinine in serum using high-performance liquid chromatography with fluorometric detection and postcolumn UV-photoirradiation system.

PubMed

Yasuda, Makoto; Ota, Tatsuhiro; Morikawa, Atsushi; Mawatari, Ken-ichi; Fukuuchi, Tomoko; Yamaoka, Noriko; Kaneko, Kiyoko; Nakagomi, Kazuya

2013-09-01

A simple and rapid method for the simultaneous determination of serum nicotine and cotinine using high-performance liquid chromatography (HPLC)-fluorometric detection with a postcolumn ultraviolet-photoirradiation system was developed. Analytes were extracted from alkalinized human serum via liquid-liquid extraction using chloroform. The organic phase was back-extracted with the acidified aqueous phase, and the analytes were directly injected into an ion-pair reversed-phase HPLC system. 6-Aminoquinoline was used as an internal standard. Nicotine, cotinine, and 6-aminoquinoline were separated within 14min. The extraction efficiency of nicotine and cotinine was greater than 91%. The linear range was 0.30-1000ng for nicotine and 0.06-1000ng for cotinine. In serum samples from smokers, the concentrations of nicotine and cotinine were 8-15ng/mL and 156-372ng/mL, respectively. Copyright © 2013 Elsevier B.V. All rights reserved.

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

PubMed

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

2008-02-01

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

Determination of MDMA, MDA, MDEA and MBDB in oral fluid using high performance liquid chromatography with native fluorescence detection.

PubMed

Concheiro, Marta; de Castro, Ana; Quintela, Oscar; López-Rivadulla, Manuel; Cruz, Angelines

2005-06-10

This paper describes the analytical methodology for the determination of MDMA, MDA, MDEA and MBDB in oral fluid. After a liquid-liquid extraction, the analysis was carried out by high performance liquid chromatography (HPLC), with fluorescence detection. The detector wavelength was fixed at 285 nm for excitation and 320 nm for emission. The mobile phase, a mixture of phosphate buffer (pH=5) and acetonitrile (75:25), and the column, Kromasil 100 C8 5 microm 250 mm x 4.6mm, allowed good separation of the compounds in an isocratic mode in only 10 min. The method was validated and showed good limits of detection (2 ng/mL) and quantitation (10 ng/mL) for all the amphetamine derivatives. No interfering substances were detected. A stability study of these compounds in oral fluid stored at three different temperatures (-18, 4 and 20 degrees C) over 10 weeks was conducted, showing a time-dependent degradation of the four compounds.

Separation and quantitation of polyethylene glycols 400 and 3350 from human urine by high-performance liquid chromatography.

PubMed

Ryan, C M; Yarmush, M L; Tompkins, R G

1992-04-01

Polyethylene glycol 3350 (PEG 3350) is useful as an orally administered probe to measure in vivo intestinal permeability to macromolecules. Previous methods to detect polyethylene glycol (PEG) excreted in the urine have been hampered by inherent inaccuracies associated with liquid-liquid extraction and turbidimetric analysis. For accurate quantitation by previous methods, radioactive labels were required. This paper describes a method to separate and quantitate PEG 3350 and PEG 400 in human urine that is independent of radioactive labels and is accurate in clinical practice. The method uses sized regenerated cellulose membranes and mixed ion-exchange resin for sample preparation and high-performance liquid chromatography with refractive index detection for analysis. The 24-h excretion for normal individuals after an oral dose of 40 g of PEG 3350 and 5 g of PEG 400 was 0.12 +/- 0.04% of the original dose of PEG 3350 and 26.3 +/- 5.1% of the original dose of PEG 400.

High-performance liquid chromatographic method for the determination of dansyl-polyamines

Treesearch

Subhash C. Minocha; Rakesh Minocha; Cheryl A. Robie

1990-01-01

This paper describes a fast reliable, and a sensitive technique for the separation and quantification of dansylated polyamines by high-performance liquid chromatography. Using a small 33 x 4.6 mm I.D., 3 ?m particle size, C18 reversed-phase cartridge column and a linear gradient of acetonitrile-heptanesulfonate (10 mM, pH 3.4...

Determination of six parabens residues in fresh-cut vegetables using QuEChERS with multi-walled carbon nanotubes and high performance liquid chromatography-tandem mass spectrometry

USDA-ARS?s Scientific Manuscript database

In this study, an optimized QuEChERS sample preparation method was developed to analyze residues of six parabens: methyl-, ethyl-, n-propyl-, isopropyl-, n-butyl-, and isobutyl-paraben in five fresh-cut vegetables (potato, broccoli, carrot, celery and cabbage) with high performance liquid chromatogr...

Purification of flavonoids from licorice using an off-line preparative two-dimensional normal-phase liquid chromatography/reversed-phase liquid chromatography method.

PubMed

Fan, Yunpeng; Fu, Yanhui; Fu, Qing; Cai, Jianfeng; Xin, Huaxia; Dai, Mei; Jin, Yu

2016-07-01

An orthogonal (71.9%) off-line preparative two-dimensional normal-phase liquid chromatography/reversed-phase liquid chromatography method coupled with effective sample pretreatment was developed for separation and purification of flavonoids from licorice. Most of the nonflavonoids were firstly removed using a self-made Click TE-Cys (60 μm) solid-phase extraction. In the first dimension, an industrial grade preparative chromatography was employed to purify the crude flavonoids. Click TE-Cys (10 μm) was selected as the stationary phase that provided an excellent separation with high reproducibility. Ethyl acetate/ethanol was selected as the mobile phase owing to their excellent solubility for flavonoids. Flavonoids co-eluted in the first dimension were selected for further purification using reversed-phase liquid chromatography. Multiple compounds could be isolated from one normal-phase fraction and some compounds with bad resolution in one-dimensional liquid chromatography could be prepared in this two-dimensional system owing to the orthogonal separation. Moreover, this two-dimensional liquid chromatography method was beneficial for the preparation of relatively trace flavonoid compounds, which were enriched in the first dimension and further purified in the second dimension. Totally, 24 flavonoid compounds with high purity were obtained. The results demonstrated that the off-line two-dimensional liquid chromatography method was effective for the preparative separation and purification of flavonoids from licorice. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rational approach to solvent system selection for liquid-liquid extraction-assisted sample pretreatment in counter-current chromatography.

PubMed

Wang, Jiajia; Gu, Dongyu; Wang, Miao; Guo, Xinfeng; Li, Haoquan; Dong, Yue; Guo, Hong; Wang, Yi; Fan, Mengqi; Yang, Yi

2017-05-15

A rational liquid-liquid extraction approach was established to pre-treat samples for high-speed counter-current chromatography (HSCCC). n-Hexane-ethyl acetate-methanol-water (4:5:4:5, v/v) and (1:5:1:5, v/v) were selected as solvent systems for liquid-liquid extraction by systematically screening K of target compounds to remove low- and high-polarity impurities in the sample, respectively. After liquid-liquid extraction was performed, 1.4g of crude sample II was obtained from 18.5g of crude sample I which was extracted from the flowers of Robinia pseudoacacia L., and then separated with HSCCC by using a solvent system composed of n-hexane-ethyl acetate-methanol-water (1:2:1:2, v/v). As a result, 31mg of robinin and 37mg of kaempferol 7-O-α-l-rhamnopyranoside were isolated from 200mg of crude sample II in a single run of HSCCC. A scale-up separation was also performed, and 160mg of robinin with 95% purity and 188mg of kaempferol 7-O-α-l-rhamnopyranoside with 97% purity were produced from 1.2g of crude sample II. Copyright © 2017 Elsevier B.V. All rights reserved.

COMPUTER-ASSISTED HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY METHOD DEVELOPMENT WITH APPLICATIONS TO THE ISOLATION AND ANALYSIS OF PHYTOPLANKTON PIGMENTS. (R826944)

EPA Science Inventory

We used chromatography modeling software to assist in HPLC method development, with the goal
of enhancing separations through the exclusive use of gradient time and column temperature. We
surveyed nine stationary phases for their utility in pigment purification and natur...

The first use of a HPLC system at a Louisiana Sugarcane Factory: What it can do for you

USDA-ARS?s Scientific Manuscript database

Alma Plantation sugarcane factory established and operated the first High Performance Liquid Chromatography (HPLC) system in Louisiana in 2015. Although many HPLC systems exist, the factory opted for a ThermoFisherTM ion chromatography (anion exchange) system with integrated pulsed amperometric det...

75 FR 47036 - Small Business Size Standards: Waiver of the Nonmanufacturer Rule

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-04

... Spectrometry (CS-MS) Systems, High Performance Liquid Chromatography (HPLC) Systems, Gas Chromatography Mass...-portable CS-MS, HPLC, GC-MS, and, ICP-MS Laboratory Equipment under PSC 6640 (Laboratory Equipment and...-portable equipment, SBA is limiting the waiver to not-portable CS-MS Systems, HPLC Systems, GC-MS Systems...

Extensive database of liquid phase diffusion coefficients of some frequently used test molecules in reversed-phase liquid chromatography and hydrophilic interaction liquid chromatography.

PubMed

Song, Huiying; Vanderheyden, Yoachim; Adams, Erwin; Desmet, Gert; Cabooter, Deirdre

2016-07-15

Diffusion plays an important role in all aspects of band broadening in chromatography. An accurate knowledge of molecular diffusion coefficients in different mobile phases is therefore crucial in fundamental column performance studies. Correlations available in literature, such as the Wilke-Chang equation, can provide good approximations of molecular diffusion under reversed-phase conditions. However, these correlations have been demonstrated to be less accurate for mobile phases containing a large percentage of acetonitrile, as is the case in hydrophilic interaction liquid chromatography. A database of experimentally measured molecular diffusion coefficients of some 45 polar and apolar compounds that are frequently used as test molecules under hydrophilic interaction liquid chromatography and reversed-phase conditions is therefore presented. Special attention is given to diffusion coefficients of polar compounds obtained in large percentages of acetonitrile (>90%). The effect of the buffer concentration (5-10mM ammonium acetate) on the obtained diffusion coefficients is investigated and is demonstrated to mainly influence the molecular diffusion of charged molecules. Diffusion coefficients are measured using the Taylor-Aris method and hence deduced from the peak broadening of a solute when flowing through a long open tube. The validity of the set-up employed for the measurement of the diffusion coefficients is demonstrated by ruling out the occurrence of longitudinal diffusion, secondary flow interactions and extra-column effects, while it is also shown that radial equilibration in the 15m long capillary is effective. Copyright © 2016 Elsevier B.V. All rights reserved.

Structural characterization of phenolics and betacyanins in Gomphrena globosa by high-performance liquid chromatography-diode array detection/electrospray ionization multi-stage mass spectrometry.

PubMed

Ferreres, Federico; Gil-Izquierdo, Angel; Valentão, Patrícia; Andrade, Paula B

2011-11-30

The metabolite profiling of Gomphrena globosa inflorescences was performed by high-performance liquid chromatography-diode array detection/electrospray ionization multi-stage mass spectrometry (HPLC-DAD/ESI-MS(n)). Based on the fragmentation patterns, 24 phenolic compounds were characterized. The identified phenolics include p-coumaric and ferulic acids, quercetin, kaempferol, isorhamnetin, and hydroxylated 6,7-methylenedioxyflavone derivatives, as well as their aglycones, none of them reported before in the species. This is also the first time that tetrahydroxy-methylenedioxyflavone derivatives and acetylglycosides are described in nature. Betacyanins were also found. This study significantly extends the knowledge of the G. globosa metabolome, by providing further insights into its phenolic composition. Copyright © 2011 John Wiley & Sons, Ltd.

Separation and quantitation of colour pigments of chili powder (Capsicum frutescens) by high-performance liquid chromatography-diode array detection.

PubMed

Cserháti, T; Forgács, E; Morais, M H; Mota, T; Ramos, A

2000-10-27

The performance of reversed-phase thin-layer (RP-TLC) and reversed-phase high-performance liquid chromatography (RP-HPLC) was compared for the separation and determination of the colour pigments of chili (Capsicum frutescens) powder using a wide variety of eluent systems. No separation of pigments was achieved in RP-TLC, however, it was established that tetrahydrofuran shows an unusually high solvent strength. RP-HPLC using water-methanol-acetonitrile gradient elution separated the chili pigments in many fractions. Diode array detection (DAD) indicated that yellow pigments are eluted earlier than the red ones and chili powder contains more yellow pigments than common paprika powders. It was established that the very different absorption spectra of pigments make the use of DAD necessary.

Core-Shell Columns in High-Performance Liquid Chromatography: Food Analysis Applications

PubMed Central

Preti, Raffaella

2016-01-01

The increased separation efficiency provided by the new technology of column packed with core-shell particles in high-performance liquid chromatography (HPLC) has resulted in their widespread diffusion in several analytical fields: from pharmaceutical, biological, environmental, and toxicological. The present paper presents their most recent applications in food analysis. Their use has proved to be particularly advantageous for the determination of compounds at trace levels or when a large amount of samples must be analyzed fast using reliable and solvent-saving apparatus. The literature hereby described shows how the outstanding performances provided by core-shell particles column on a traditional HPLC instruments are comparable to those obtained with a costly UHPLC instrumentation, making this novel column a promising key tool in food analysis. PMID:27143972

Determination of erythromycin in human plasma, using column liquid chromatography with a polymeric packing material, alkaline mobile phase and amperometric detection.

PubMed

Nilsson, L G; Walldorf, B; Paulsen, O

1987-12-25

A method based on column liquid chromatography was developed for determination of plasma concentrations of erythromycin. PRP-1, a polymeric type of packing material suitable for chromatography and amperometric detection at high pH, was used. The effect of pH on the column performance and on the electrochemical response was studied. A pH of ca. 10 was found to be optimal. After extraction with tert.-butyl methyl ether, plasma concentrations down to 0.2 mumol/l could be measured, using automated sample injection. Oleandomycin was used as internal standard. The method was used for determination of plasma concentrations in a pharmacokinetic study under steady-state conditions.

Simultaneous determination of five minor coumarins and flavonoids in Glycyrrhiza uralensis by solid-phase extraction and high-performance liquid chromatography/electrospray ionization tandem mass spectrometry.

PubMed

Qiao, Xue; Liu, Chun-Fang; Ji, Shuai; Lin, Xiong-Hao; Guo, De-An; Ye, Min

2014-02-01

Minor phenolic compounds in licorice (Glycyrrhiza uralensis) have recently been proved for diverse bioactivities and favorable bioavailability, indicating that they may play an important role in the therapeutic effects or herb-drug interactions of licorice. However, so far, their abundance in licorice remains unknown. In this study, a reliable solid-phase extraction coupled with a high-performance liquid chromatography and diode array detection method was established to determine the minor phenolic compounds in licorice. The analytes were enriched by a three-step solid-phase extraction method, and then separated on a YMC ODS-A column by gradient elution. Five coumarins and flavonoids were identified by electrospray ionization tandem mass spectrometry, and then quantified using high-performance liquid chromatography and diode array detection. The amounts of glycycoumarin, dehydroglyasperin C, glycyrol, licoflavonol, and glycyrin in G. uralensis were 0.81 ± 0.28, 1.25 ± 0.59, 0.20 ± 0.08, 0.12 ± 0.04, and 0.17 ± 0.08 mg/g, respectively. Abundances of these compounds in other Glycyrrhiza species (G. glabra, G. inflata, and G. yunnanesis) were remarkably lower than G. uralensis. Georg Thieme Verlag KG Stuttgart · New York.

Simultaneous determination of phenytoin, carbamazepine, and 10,11-carbamazepine epoxide in human plasma by high-performance liquid chromatography with ultraviolet detection.

PubMed

Bhatti, M M; Hanson, G D; Schultz, L

1998-03-01

The Bioanalytical Chemistry Department at the Madison facility of Covance Laboratories, has developed and validated a simple and sensitive method for the simultaneous determination of phenytoin (PHT), carbamazepine (CBZ) and 10,11-carbamazepine epoxide (CBZ-E) in human plasma by high-performance liquid chromatography with 10,11 dihydrocarbamazepine as the internal standard. Acetonitrile was added to plasma samples containing PHT, CBZ and CBZ-E to precipitate the plasma proteins. After centrifugation, the acetonitrile supernatant was transferred to a clean tube and evaporated under N2. The dried sample extract was reconstituted in 0.4 ml of mobile phase and injected for analysis by high-performance liquid chromatography. Separation was achieved on a Spherisorb ODS2 analytical column with a mobile phase of 18:18:70 acetonitrile:methanol:potassium phosphate buffer. Detection was at 210 nm using an ultraviolet detector. The mean retention times of CBZ-E, PHT and CBZ were 5.8, 9.9 and 11.8 min, respectively. Peak height ratios were fit to a least squares linear regression algorithm with a 1/(concentration)2 weighting. The method produces acceptable linearity, precision and accuracy to a minimum concentration of 0.050 micrograms ml-1 in human plasma. It is also simple and convenient, with no observable matrix interferences.

An efficient approach to identify different chemical markers between fibrous root and rhizome of Anemarrhena asphodeloides by ultra high-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry with multivariate statistical analysis.

PubMed

Wang, Fang-Xu; Yuan, Jian-Chao; Kang, Li-Ping; Pang, Xu; Yan, Ren-Yi; Zhao, Yang; Zhang, Jie; Sun, Xin-Guang; Ma, Bai-Ping

2016-09-10

An ultra high-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry approach coupled with multivariate statistical analysis was established and applied to rapidly distinguish the chemical differences between fibrous root and rhizome of Anemarrhena asphodeloides. The datasets of tR-m/z pairs, ion intensity and sample code were processed by principal component analysis and orthogonal partial least squares discriminant analysis. Chemical markers could be identified based on their exact mass data, fragmentation characteristics, and retention times. And the new compounds among chemical markers could be isolated rapidly guided by the ultra high-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry and their definitive structures would be further elucidated by NMR spectra. Using this approach, twenty-four markers were identified on line including nine new saponins and five new steroidal saponins of them were obtained in pure form. The study validated this proposed approach as a suitable method for identification of the chemical differences between various medicinal parts in order to expand medicinal parts and increase the utilization rate of resources. Copyright © 2016 Elsevier B.V. All rights reserved.

High performance liquid chromatography coupled with resonance Rayleigh scattering for the detection of three fluoroquinolones and mechanism study

NASA Astrophysics Data System (ADS)

Zhou, Mingqiong; Peng, Jingdong; He, Rongxing; He, Yuting; Zhang, Jing; Li, Aiping

2015-02-01

A reliable and versatile high performance liquid chromatography coupled with resonance Rayleigh scattering method was established for the determination of three fluoroquinolones, including levofloxacin, norfloxacin and enrofloxacin in water sample and human urine sample. In pH 4.4-4.6 Britton-Robinson buffer medium, the fluoroquinolones separated by high performance liquid chromatography could react with erythrosine to form 1:1 ion-association complexes, which could make contributions to the great enhancement of RRS. The resonance Rayleigh scattering signal was recorded at λex = λem = 330 nm. The resonance Rayleigh scattering spectral characteristics of the drugs and the experimental conditions such as pH, detection wavelength, erythrosine concentration, flow rate, the length of reaction tube were studied. Quantum chemistry calculation, Fourier transform infrared spectroscopy and absorption spectroscopy were used to discuss the reaction mechanism. The recoveries of samples added standard ranged from 97.53% to 102.00%, and the relative standard deviation was below 4.64%. The limit of detection (S/N = 3) of 0.05-0.12 μg mL-1 was reached, and the linear regression coefficients were all above 0.999. The proposed method was proved as a simple, low cost and high sensitivity method.

Liquid Chromatography in 1982.

ERIC Educational Resources Information Center

Freeman, David H.

1982-01-01

Reviews trends in liquid chromatography including apparatus, factors affecting efficient separation of a mixture (peak sharpness and speed), simplified problem-solving, adsorption, bonded phase chromatography, ion selectivity, and size exclusion. The current trend is to control chemical selectivity by the liquid phase. (Author/JN)

[Determination of sugars, organic acids and alcohols in microbial consortium fermentation broth from cellulose using high performance liquid chromatography].

PubMed

Jiang, Yan; Fan, Guifang; Du, Ran; Li, Peipei; Jiang, Li

2015-08-01

A high performance liquid chromatographic method was established for the determination of metabolites (sugars, organic acids and alcohols) in microbial consortium fermentation broth from cellulose. Sulfate was first added in the samples to precipitate calcium ions in microbial consortium culture medium and lower the pH of the solution to avoid the dissociation of organic acids, then the filtrates were effectively separated using high performance liquid chromatography. Cellobiose, glucose, ethanol, butanol, glycerol, acetic acid and butyric acid were quantitatively analyzed. The detection limits were in the range of 0.10-2.00 mg/L. The linear correlation coefficients were greater than 0.999 6 in the range of 0.020 to 1.000 g/L. The recoveries were in the range of 85.41%-115.60% with the relative standard deviations of 0.22% -4.62% (n = 6). This method is accurate for the quantitative analysis of the alcohols, organic acids and saccharides in microbial consortium fermentation broth from cellulose.

Reversed-Phase High-Performance Liquid Chromatography for the Quantification and Optimization for Extracting 10 Kinds of Carotenoids in Pepper (Capsicum annuum L.) Leaves.

PubMed

Li, Jing; Xie, Jianming; Yu, Jihua; Lv, Jian; Zhang, Junfeng; Wang, Xiaolong; Wang, Cheng; Tang, Chaonan; Zhang, Yingchun; Dawuda, Mohammed Mujitaba; Zhu, Daiqiang; Ma, Guoli

2017-09-27

Carotenoids are considered to be crucial elements in many fields and, furthermore, the significant factor in pepper leaves under low light and chilling temperature. However, little literature focused on the method to determinate and extract the contents of carotenoid compositions in pepper leaves. Therefore, a time-saving and highly sensitive reversed-phase high-performance liquid chromatography method for separation and quantification of 10 carotenoids was developed, and an optimized technological process for carotenoid composition extraction in pepper leaves was established for the first time. Our final method concluded that six xanthophylls eluted after about 9-26 min. In contrast, four carotenes showed higher retention times after nearly 28-40 min, which significantly shortened time and improved efficiency. Meanwhile, we suggested that 8 mL of 20% KOH-methanol solution should be added to perform saponification at 60 °C for 30 min. The ratio of solid-liquid was 1:8, and the ultrasound-assisted extraction time was 40 min.

Determination of rifampicin in human plasma by high-performance liquid chromatography coupled with ultraviolet detection after automatized solid-liquid extraction.

PubMed

Louveau, B; Fernandez, C; Zahr, N; Sauvageon-Martre, H; Maslanka, P; Faure, P; Mourah, S; Goldwirt, L

2016-12-01

A precise and accurate high-performance liquid chromatography (HPLC) quantification method of rifampicin in human plasma was developed and validated using ultraviolet detection after an automatized solid-phase extraction. The method was validated with respect to selectivity, extraction recovery, linearity, intra- and inter-day precision, accuracy, lower limit of quantification and stability. Chromatographic separation was performed on a Chromolith RP 8 column using a mixture of 0.05 m acetate buffer pH 5.7-acetonitrile (35:65, v/v) as mobile phase. The compounds were detected at a wavelength of 335 nm with a lower limit of quantification of 0.05 mg/L in human plasma. Retention times for rifampicin and 6,7-dimethyl-2,3-di(2-pyridyl) quinoxaline used as internal standard were respectively 3.77 and 4.81 min. This robust and exact method was successfully applied in routine for therapeutic drug monitoring in patients treated with rifampicin. Copyright © 2016 John Wiley & Sons, Ltd.

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.

Evaluation of phenolic compounds in virgin olive oil by direct injection in high-performance liquid chromatography with fluorometric detection.

PubMed

Selvaggini, Roberto; Servili, Maurizio; Urbani, Stefania; Esposto, Sonia; Taticchi, Agnese; Montedoro, GianFrancesco

2006-04-19

Hydrophilic phenols are the most abundant natural antioxidants of virgin olive oil (VOO), in which tocopherols and carotenes are also present. The prevalent classes of hydrophilic phenols found in VOO are phenyl alcohols, phenolic acids, secoiridoids such as the dialdehydic form of decarboxymethyl elenolic acid linked to (3,4-dihydroxyphenyl)ethanol or (p-hydroxypheny1)ethanol (3,4-DHPEA-EDA or p-HPEA-EDA) and an isomer of the oleuropein aglycon (3,4-DHPEA-EA), lignans such as (+)-1-acetoxypinoresinol and (+)-pinoresinol, and flavonoids. A new method for the analysis of VOO hydrophilic phenols by direct injection in high-performance liquid chromatography (HPLC) with the use of a fluorescence detector (FLD) has been proposed and compared with the traditional liquid-liquid extraction technique followed by the HPLC analysis utilizing a diode array detector (DAD) and a FLD. Results show that the most important classes of phenolic compounds occurring in VOO can be evaluated using HPLC direct injection. The efficiency of the new method, as compared to the liquid-liquid extraction, was higher to quantify phenyl alcohols, lignans, and 3,4-DHPEA-EA and lower for the evaluation of 3,4-DHPEA-EDA and p-HPEA-EDA.

Ion pair-based dispersive liquid-liquid microextraction followed by high performance liquid chromatography as a new method for determining five folate derivatives in foodstuffs.

PubMed

Nojavan, Yones; Kamankesh, Marzieh; Shahraz, Farzaneh; Hashemi, Maryam; Mohammadi, Abdorreza

2015-05-01

A novel technique for simultaneous determination of five folate derivatives in various food matrices was developed by ion pair-based dispersive liquid-liquid microextraction (IP-DLLME) combined with high-performance liquid chromatography (HPLC). In the proposed method, N-methyl-N,N-dioctyloctan-1-ammonium chloride (aliquat-336) was used as an ion-pair reagent. Effective variables of microextraction process were optimized. Under optimum conditions, the method yielded a linear calibration curve ranging from 1-200 ng g(-1) with correlation coefficients (r(2)) higher than 0.98. The relative standard deviation for the seven analyses was 5.2-7.4%. Enrichment factors for the five folates ranged between 108-135. Limits of detection were 2-4.1 ng g(-1). A comparison of this method with other methods described that the new proposed method is rapid and accurate, and gives very good enrichment factors and detection limits for determining five folate derivatives. The newly developed method was successfully applied for the determination of five folate derivatives in wheat flour, egg yolk and orange juice samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Sensitive determination of melamine in milk and powdered infant formula samples by high-performance liquid chromatography using dabsyl chloride derivatization followed by dispersive liquid-liquid microextraction.

PubMed

Faraji, M; Adeli, M

2017-04-15

A new and sensitive pre-column derivatization with dabsyl chloride followed by dispersive liquid-liquid microextraction was developed for the analysis of melamine (MEL) in raw milk and powdered infant formula samples by high performance liquid chromatography (HPLC) with visible detection. Derivatization with dabsyl chloride leads to improving sensitivity and hydrophobicity of MEL. Under optimum conditions of derivatization and microextraction steps, the method yielded a linear calibration curve ranging from 1.0 to 500μgL -1 with a determination coefficient (R 2 ) of 0.9995. Limit of detection and limit of quantification were 0.1 and 0.3μgL -1 , respectively. The relative standard deviation (RSD%) for intra-day (repeatability) and inter-day (reproducibility) at 25 and 100μgL -1 levels of MEL was less than 7.0% (n=6). Finally, the proposed method was successfully applied for the preconcentration and determination of MEL in different raw milk and powdered infant formula, and satisfactory results were obtained (relative recovery ⩾94%). Copyright © 2016 Elsevier Ltd. All rights reserved.

Application and optimization of microwave-assisted extraction and dispersive liquid-liquid microextraction followed by high-performance liquid chromatography for sensitive determination of polyamines in turkey breast meat samples.

PubMed

Bashiry, Moein; Mohammadi, Abdorreza; Hosseini, Hedayat; Kamankesh, Marzieh; Aeenehvand, Saeed; Mohammadi, Zaniar

2016-01-01

A novel method based on microwave-assisted extraction and dispersive liquid-liquid microextraction (MAE-DLLME) followed by high-performance liquid chromatography (HPLC) was developed for the determination of three polyamines from turkey breast meat samples. Response surface methodology (RSM) based on central composite design (CCD) was used to optimize the effective factors in DLLME process. The optimum microextraction efficiency was obtained under optimized conditions. The calibration graphs of the proposed method were linear in the range of 20-200 ng g(-1), with the coefficient determination (R(2)) higher than 0.9914. The relative standard deviations were 6.72-7.30% (n = 7). The limits of detection were in the range of 0.8-1.4 ng g(-1). The recoveries of these compounds in spiked turkey breast meat samples were from 95% to 105%. The increased sensitivity in using the MAE-DLLME-HPLC-UV has been demonstrated. Compared with previous methods, the proposed method is an accurate, rapid and reliable sample-pretreatment method. Copyright © 2015 Elsevier Ltd. All rights reserved.

Coupling of solvent-based de-emulsification dispersive liquid-liquid microextraction with high performance liquid chromatography for simultaneous simple and rapid trace monitoring of 2,4-dichlorophenoxyacetic acid and 2-methyl-4-chlorophenoxyacetic acid.

PubMed

Behbahani, Mohammad; Najafi, Fatemeh; Bagheri, Saman; Bojdi, Majid Kalate; Hassanlou, Parmoon Ghareh; Bagheri, Akbar

2014-04-01

A simple, rapid, and efficient sample pretreatment technique, based on solvent-based de-emulsification dispersive liquid-liquid microextraction (SD-DLLME), followed by high performance liquid chromatography (HPLC) has been developed for simultaneous preconcentration and trace detection of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-methyl-4-chlorophenoxyacetic acid (MCPA) in water and urine samples. Some parameters such as acidity of solution, the amount of salt, type, and volume of extraction solvents, type of disperser/de-emulsifier solvent, and its volume were investigated and optimized. Under optimum extraction conditions, the limits of detections (LODs) of this method for MCPA and 2,4-D were 0.2 and 0.6 μg L(-1) (based on 3S(b)/m) in water and 0.4 and 1.6 μg L(-1) in urine, respectively. Furthermore, dynamic linear range of this method for MCPA and 2,4-D was 1-300 and 2-400 μg L(-1), repectively. Finally, the applicability of the proposed method was evaluated by extraction and determination of the herbicides in urine and different water samples.

Air-assisted liquid-liquid microextraction integrated with QuEChERS for determining endocrine-disrupting compounds in fish by high-performance liquid chromatography-tandem mass spectrometry.

PubMed

Luo, Zhoufei; Lu, Jing; Li, Haipu; Tu, Yi; Wan, Yuehao; Yang, Zhaoguang

2018-09-15

A new, sensitive, and rapid method based on the Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) approach and air-assisted liquid-liquid microextraction (AALLME) technology was developed for the determination of 20 endocrine-disrupting compounds (EDCs) in fish by high-performance liquid chromatography-tandem mass spectrometry. The method first integrates AALLME into QuEChERS to achieve clean-up and enrichment of the EDCs in one step. A self-made glass tube was enfolded with plasticine to withstand the high centrifugal force. The established method was developed by optimization of the parameters. High linearities (R 2  > 0.9924) and recoveries (78.2-118.6%) at three spiked levels (5, 10, and 20 ng g -1 ), and low relative standard deviation values (1.1-14.5%) and limits of detection (0.03-0.80 ng g -1 ) were obtained. The method comparison shows that the proposed method is superior as it involves less organic solvent usage, simple operation and high efficiency. This method was successfully applied to different fishes for analyzing EDCs. Copyright © 2018 Elsevier Ltd. All rights reserved.

From functional food to medicinal product: Systematic approach in analysis of polyphenolics from propolis and wine

PubMed Central

Medić-Šarić, Marica; Rastija, Vesna; Bojić, Mirza; Maleš, Željan

2009-01-01

In the last decade we have been working on standardization of propolis extract and determination of active constituents of wine those are rich in polyphenolics and have nutritional as well as therapeutic value. Here we are summarizing our results and providing overview on systematic approach how to analyse natural products rich in flavonoids and phenolic acids. Chromatographic methods (thin layer chromatography and high performance liquid chromatography) were used for identification, quantification, and characterization of individual flavonoid or phenolic acid. Total content of active constituents and antioxidant activity were determined by spectrophotometry. Pharmacokinetic parameters were determined by high performance liquid chromatography and using appropriate software. Quantitative structure-activity relationship study of antioxidant activity was conducted, as well as assessment of prolonged propolis supplementation on antioxidative status of organism. Thin layer chromatography-densitometry has been proven as quick and reliable method for standard analysis of propolis and wine; the best mobile phase being chloroform – methanol – formic acid (98–100%) in ratio 44 : 3.5 : 2.5 (v/v). Higher number of polyphenolics was determined by high performance liquid chromatography; 15 compared to 9 by thin layer chromatography. Interactions in situ with acetylsalicylic acid were detected with most of polyphenolics analysed. Plasma protein binding and blood-barrier penetration was greatest for flavone. The interactions with human serum albumin have been grater than 95% for all flavonoids analysed. The prolonged propolis consumption increased superoxide dismutase activity. The necessity of standardization of natural products and their registration as functional nutraceuticals demand easy, quick and inexpensive methods of analysis. In this work we provided overview of analytical part for polyphenolics that could be used as data for possible registration of final products either as functional food or medicinal product. This feature introduces the readers to the authors' research through a concise overview of the selected topic. Reference to important work from others in the field is included. PMID:19624827

Lipidomic analysis of biological samples: Comparison of liquid chromatography, supercritical fluid chromatography and direct infusion mass spectrometry methods.

PubMed

Lísa, Miroslav; Cífková, Eva; Khalikova, Maria; Ovčačíková, Magdaléna; Holčapek, Michal

2017-11-24

Lipidomic analysis of biological samples in a clinical research represents challenging task for analytical methods given by the large number of samples and their extreme complexity. In this work, we compare direct infusion (DI) and chromatography - mass spectrometry (MS) lipidomic approaches represented by three analytical methods in terms of comprehensiveness, sample throughput, and validation results for the lipidomic analysis of biological samples represented by tumor tissue, surrounding normal tissue, plasma, and erythrocytes of kidney cancer patients. Methods are compared in one laboratory using the identical analytical protocol to ensure comparable conditions. Ultrahigh-performance liquid chromatography/MS (UHPLC/MS) method in hydrophilic interaction liquid chromatography mode and DI-MS method are used for this comparison as the most widely used methods for the lipidomic analysis together with ultrahigh-performance supercritical fluid chromatography/MS (UHPSFC/MS) method showing promising results in metabolomics analyses. The nontargeted analysis of pooled samples is performed using all tested methods and 610 lipid species within 23 lipid classes are identified. DI method provides the most comprehensive results due to identification of some polar lipid classes, which are not identified by UHPLC and UHPSFC methods. On the other hand, UHPSFC method provides an excellent sensitivity for less polar lipid classes and the highest sample throughput within 10min method time. The sample consumption of DI method is 125 times higher than for other methods, while only 40μL of organic solvent is used for one sample analysis compared to 3.5mL and 4.9mL in case of UHPLC and UHPSFC methods, respectively. Methods are validated for the quantitative lipidomic analysis of plasma samples with one internal standard for each lipid class. Results show applicability of all tested methods for the lipidomic analysis of biological samples depending on the analysis requirements. Copyright © 2017 Elsevier B.V. All rights reserved.

Sensitive quantification of coixol, a potent insulin secretagogue, in Scoparia dulcis extract using high-performance liquid chromatography combined with tandem mass spectrometry and UV detection.

PubMed

Ali, Arslan; Haq, Faraz Ul; Ul Arfeen, Qamar; Sharma, Khaga Raj; Adhikari, Achyut; Musharraf, Syed Ghulam

2017-10-01

Diabetes is a major global health problem which requires new studies for its prevention and control. Scoparia dulcis, a herbal product, is widely used for treatment of diabetes. Recent studies demonstrate coixol as a potent and nontoxic insulin secretagog from S. dulcis. This study focuses on developing two quantitative methods of coixol in S. dulcis methanol-based extracts. Quantification of coixol was performed using high-performance liquid chromatography-tandem mass spectrometry (method 1) and high-performance liquid chromatography-ultraviolet detection (method 2) with limits of detection of 0.26 and 11.6 pg/μL, respectively, and limits of quantification of 0.78 and 35.5 pg/μL, respectively. S. dulcis is rich in coixol content with values of 255.5 ± 2.1 mg/kg (method 1) and 220.4 ± 2.9 mg/kg (method 2). Excellent linearity with determination coefficients >0.999 was achieved for calibration curves from 10 to 7500 ng/mL (method 1) and from 175 to 7500 ng/mL (method 2). Good accuracy (bias < -8.6%) and precision (RSD < 8.5%) were obtained for both methods. Thus, they can be employed to analyze coixol in plant extracts and herbal formulations. Copyright © 2017 John Wiley & Sons, Ltd.

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

PubMed

Varelis, P; Jeskelis, R

2008-10-01

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

Recent trends in the impurity profile of pharmaceuticals

PubMed Central

Pilaniya, Kavita; Chandrawanshi, Harish K.; Pilaniya, Urmila; Manchandani, Pooja; Jain, Pratishtha; Singh, Nitin

2010-01-01

Various regulatory authorities such as the International Conference on Harmonization (ICH), the United States Food and Drug administration (FDA), and the Canadian Drug and Health Agency (CDHA) are emphasizing on the purity requirements and the identification of impurities in Active Pharmaceutical Ingredients (APIs). The various sources of impurity in pharmaceutical products are — reagents, heavy metals, ligands, catalysts, other materials like filter aids, charcoal, and the like, degraded end products obtained during \\ after manufacturing of bulk drugs from hydrolysis, photolytic cleavage, oxidative degradation, decarboxylation, enantiomeric impurity, and so on. The different pharmacopoeias such as the British Pharmacopoeia, United State Pharmacopoeia, and Indian Pharmacopoeia are slowly incorporating limits to allowable levels of impurities present in APIs or formulations. Various methods are used to isolate and characterize impurities in pharmaceuticals, such as, capillary electrophoresis, electron paramagnetic resonance, gas–liquid chromatography, gravimetric analysis, high performance liquid chromatography, solid-phase extraction methods, liquid–liquid extraction method, Ultraviolet Spectrometry, infrared spectroscopy, supercritical fluid extraction column chromatography, mass spectrometry, Nuclear magnetic resonance (NMR) spectroscopy, and RAMAN spectroscopy. Among all hyphenated techniques, the most exploited techniques for impurity profiling of drugs are Liquid Chromatography (LC)-Mass Spectroscopy (MS), LC-NMR, LC-NMR-MS, GC-MS, and LC-MS. This reveals the need and scope of impurity profiling of drugs in pharmaceutical research. PMID:22247862

Hydrophilic interaction liquid chromatography-solid phase extraction directly combined with protein precipitation for the determination of triptorelin in plasma.

PubMed

Wang, Jixia; Kong, Song; Yan, Jingyu; Jin, Gaowa; Guo, Zhimou; Shen, Aijin; Xu, Junyan; Zhang, Xiuli; Zou, Lijuan; Liang, Xinmiao

2014-06-01

Peptide drugs play a critical role in therapeutic treatment. However, as the complexity of plasma, determination of peptide drugs using liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a daunting task. To solve this problem, hydrophilic interaction liquid chromatography-solid phase extraction (HILIC-SPE) directly combined with protein precipitation (PPT) was developed for the selective extraction of triptorelin from plasma. The extracts were analyzed by reversed-phase liquid chromatography (RPLC). Proteins, phospholipids and highly polar interferences could be removed from plasma by the efficient combination of PPT, HILIC-SPE and RPLC-MS/MS. This method was evaluated by matrix effect, recovery and process efficiency at different concentration levels (50, 500 and 5,000 ng/mL) of triptorelin. Furthermore, the performance of HILIC-SPE was compared with that of reversed-phase C18 SPE and hydrophilic lipophilic balance (Oasis HLB) SPE. Among them, HILIC-SPE provided the minimum matrix effect (ranging from 96.02% to 103.41%), the maximum recovery (ranging from 80.68% to 90.54%) and the satisfactory process efficiency (ranging from 82.83% to 92.95%). The validated method was successfully applied to determine triptorelin in rat plasma. Copyright © 2014 Elsevier B.V. All rights reserved.

Establishment of quantitative retention-activity model by optimized microemulsion liquid chromatography.

PubMed

Xu, Liyuan; Gao, Haoshi; Li, Liangxing; Li, Yinnong; Wang, Liuyun; Gao, Chongkai; Li, Ning

2016-12-23

The effective permeability coefficient is of theoretical and practical importance in evaluation of the bioavailability of drug candidates. However, most methods currently used to measure this coefficient are expensive and time-consuming. In this paper, we addressed these problems by proposing a new measurement method which is based on the microemulsion liquid chromatography. First, the parallel artificial membrane permeability assays model was used to determine the effective permeability of drug so that quantitative retention-activity relationships could be established, which were used to optimize the microemulsion liquid chromatography. The most effective microemulsion system used a mobile phase of 6.0% (w/w) Brij35, 6.6% (w/w) butanol, 0.8% (w/w) octanol, and 86.6% (w/w) phosphate buffer (pH 7.4). Next, support vector machine and back-propagation neural networks are employed to develop a quantitative retention-activity relationships model associated with the optimal microemulsion system, and used to improve the prediction ability. Finally, an adequate correlation between experimental value and predicted value is computed to verify the performance of the optimal model. The results indicate that the microemulsion liquid chromatography can serve as a possible alternative to the PAMPA method for determination of high-throughput permeability and simulation of biological processes. Copyright © 2016. Published by Elsevier B.V.

High-pressure liquid chromatography: A brief introduction and its application in analyzing the degradation of a C-ether (Thio-ether) liquid lubricant

NASA Technical Reports Server (NTRS)

1983-01-01

The general principles of classical liquid chromatography and high pressure liquid chromatography (HPLC) are reviewed, and their advantages and disadvantages are compared. Several chromatographic techniques are reviewed, and the analytical separation of a C-ether liquid lubricant by each technique is illustrated. A practical application of HPLC is then demonstrated by analyzing a degraded C-ether liquid lubricant from full scale, high temperature bearing tests.

High Performance Liquid Chromatography-Diode Array Detector Method for the Simultaneous Determination of Five Compounds in the Pulp and Seed of Sea Buckthorn.

PubMed

Zhao, Lu; Wen, E; Upur, Halmuart; Tian, Shuge

2017-01-01

Sea buckthorn ( Hippophae rhamnoides L.) as a traditional Chinese medicinal plant has various uses in Xinjiang. A reversed-phase rapid-resolution liquid-chromatography method with diode array detector was developed for simultaneous determination of protocatechuic acid, rutin, quercetin, kaempferol, and isorhamnetin in the pulp and seed of sea buckthorn, a widely used traditional Chinese medicine for promoting metabolism and treating scurvy and other diseases. Compounds were separated on an Agilent ZORBAX SB-C18 column (4.6 mm × 250 mm, 5 μm; USA) with gradient elution using methanol and 0.4% phosphoric acid (v/v) at 1.0 mL/min. Detection wavelength was set at 280 nm. The fruits of wild sea buckthorn were collected from Wushi County in Aksu, Xinjiang Province. The RSD of precision test of the five compounds were in the range of 0.60-2.22%, and the average recoveries ranged from 97.36% to 101.19%. Good linearity between specific chromatographic peak and component qualities were observed in the investigated ranges for all the analytes ( R 2 > 0.9997). The proposed method was successfully applied to determine the levels of five active components in sea buckthorn samples from Aksu in Xinjiang. The proposed method is simple, fast, sensitive, accurate, and suitable for quantitative assessment of the pulp and seed of sea buckthorn. Quantitative analysis method of protocatechuic acid, rutin, quercetin, kaempferol, and isorhamnetin in the extract of sea buckthorn pulp and seed is developed by high-performance liquid chromatography (HPLC) diode array detection.This method is simple and accurate; has strong specificity, good precision, and high recovery rate; and provides a reliable basis for further development of the substances in the pulp and seed of sea buckthorn.The method is widely used for content determination of active ingredients or physiologically active components in traditional Chinese medicine and its preparation Abbreviation used: PR: protocatechuic acid, RU: rutin, QU: quercetin, KA: kaempferol, IS: isorhamnetin, HPLC: high-performance liquid chromatography, HPLC-DAD: high performance liquid chromatographydiode array detector, LOD: linearity and limit of detection, LOQ: limit of quantitation, RSD: relative standard deviation.

Identification of cardiac glycosides in fractions from Periploca forrestii by high-performance liquid chromatography/diode-array detection/electrospray ionization multi-stage tandem mass spectrometry and liquid chromatography/nuclear magnetic resonance.

PubMed

Li, Yong; Wu, Xianfu; Li, Jianbei; Wang, Yinghong; Yu, Shishan; Lv, Haining; Qu, Jing; Abliz, Zeper; Liu, Jing; Liu, Yuanyan; Du, Dan

2010-02-01

Cardiac glycosides are a class of naturally occurring compounds that are characterized by some interesting biological activities and are widely distributed in the plant kingdom and can also be found in some animals. There is an interest in the chemical characterization of these molecules due to their toxicity and their use in medicines. In the study reported here, a combination of electrospray ionization tandem mass spectrometry with high-performance liquid chromatography equipped with diode-array detector (HPLC-DAD/ESI-MS(n)), and hyphenation to both liquid chromatography and nuclear magnetic resonance spectroscopy (HPLC/NMR) were utilized for the on-line analyses of cardiac glycosides from Periploca forrestii. The fragmentation patterns and (1)H NMR spectra of nine isolated cardiac glycosides were investigated; their fragmentation rules and (1)H NMR spectral characteristics were summarized and applied to the structural identification of similar constituents in fractions from P. forrestii. As a result, a total of nine trace cardiac glycosides were tentatively determined by analyses of accurate molecular masses, representative fragment ions and characteristic (1)H NMR signals provided by HPLC/high-resolution mass spectrometry (HRMS), HPLC-DAD/ESI-MS(n) and HPLC/(1)H NMR experiments, respectively. Of these, eight (2-9) are new compounds and one (1) is reported from P. forrestii for the first time. Results of the present study can benefit the rapid identification and targeted isolation of new cardiac glycosides from crude plant extracts. 2009 Elsevier B.V. All rights reserved.

Evaluation between ultrahigh pressure liquid chromatography and high-performance liquid chromatography analytical methods for characterizing natural dyestuffs.

PubMed

Serrano, Ana; van Bommel, Maarten; Hallett, Jessica

2013-11-29

An evaluation was undertaken of ultrahigh pressure liquid chromatography (UHPLC) in comparison to high-performance liquid chromatography (HPLC) for characterizing natural dyes in cultural heritage objects. A new UHPLC method was optimized by testing several analytical parameters adapted from prior UHPLC studies developed in diverse fields of research. Different gradient elution programs were tested on seven UHPLC columns with different dimensions and stationary phase compositions by applying several mobile phases, flow rates, temperatures, and runtimes. The UHPLC method successfully provided more improved data than that achieved by the HPLC method. Indeed, even though carminic acid has shown circa 146% higher resolution with HPLC, UHPLC resulted in an increase of 41-61% resolution and a decrease of 91-422% limit of detection, depending on the dye compound. The optimized method was subsequently assigned to analyse 59 natural reference materials, in which 85 different components were ascribed with different physicochemical properties, in order to create a spectral database for future characterization of dyes in cultural heritage objects. The majority of these reference samples could be successfully distinguished with one single method through the examination of these compounds' retention times and their spectra acquired with a photodiode array detector. These results demonstrate that UHPLC analyses are extremely valuable for the acquisition of more precise chromatographic information concerning natural dyes with complex mixtures of different and/or closely related physicochemical properties, essential for distinguishing similar species of plants and animals used to colour cultural heritage objects. Copyright © 2013 Elsevier B.V. All rights reserved.

Simultaneous determination of five major compounds in the traditional medicine Pyeongwee-San by high performance liquid chromatography-diode array detection and liquid chromatography-mass spectrometry/mass spectrometry.

PubMed

Lee, Bohyoung; Weon, Jin Bae; Yun, Bo-Ra; Lee, Jiwoo; Eom, Min Rye; Ma, Choong Je

2014-01-01

Pyeongwee-San (PWS) has been widely used for treating acute gastritis, chronic, and gastritis. In this paper, simultaneous determination of five compounds (naringin, hesperidin, glycyrrhizin, atractylenolide III, and magnolol) from traditional medicine PWS using the high performance liquid chromatography (HPLC) was established for quality control. Optimum separations were obtained with a SHISEIDO C18 reverse-phase column by gradient elution with 0.1% Trifluoroacetic acid (TFA) water-acetonitrile as the mobile phase. The flow rate was 1 mL/min and detection wavelength was set at 205 nm and 250 nm. Validation of the analytical method was evaluated by linearity, precision, and accuracy test. The calibration curves were linear over the established range with R (2) > 0.9978. The limit of detection (LOD) and limit of quantification (LOQ) ranged from 0.09 to 0.43 and 0.27 to 1.29 μg/mL. The method exhibited intra-day and inter-day precision range between 0.01-1.86% and 0.04-0.35% respectively. The recoveries of five compounds in PWS were in the range between 93.18-106.40%, and 0.20-1.51%. The application of this method was identified through the successful analysis of five compounds in 12 batches of PWS. In addition, identification of five compounds was confirmed by a liquid chromatography method and mass spectrometry. The HPLC method was could be accomplished to the quality control and stable experiment for the preparations consisted of five major compounds.

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

PubMed

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

2018-04-21

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

A rapid method for the simultaneous determination of 25 anti-hypertensive compounds in dietary supplements using ultra-high-pressure liquid chromatography.

PubMed

Heo, Seok; Yoo, Geum Joo; Choi, Ji Yeon; Park, Hyoung Joon; Park, Sung-Kwan; Baek, Sun Young

2016-11-01

A novel, stable, simple and specific ultra-performance liquid chromatography method with ultraviolet detection (205 nm) for the simultaneous analysis of 25 anti-hypertensive substances was developed. The method was validated according to the International Conference of Harmonisation guidelines with respect to linearity, accuracy, precision, limit of detection (LOD), limit of quantitation (LOQ) and stability. From the ultra-performance liquid chromatography results, we identified the LOD and LOQ of solid samples to be 0.20-1.00 and 0.60-3.00 μg ml -1 , respectively, while those of liquid samples were 0.30-1.20 and 0.90-3.60 μg ml -1 , respectively. The linearity exceeded 0.9999, and the intra- and inter-day precisions were 0.15-6.48% and 0.28-8.67%, respectively. The intra- and inter-day accuracies were 82.25-111.42% and 80.70-115.64%, respectively, and the stability was lower than 12.9% (relative standard deviation). This method was applied to the monitoring of 97 commercially available dietary supplements obtained in Korea, such as pills, soft capsules, hard capsules, liquids, powders and tablets. The proposed method is accurate, precise and of high quality, and can be used for the routine, reproducible analysis and control of 25 anti-hypertensive substances in various dietary supplements. The work presented herein may help to prevent incidents related to food adulteration and restrict the illegal food market.

Determination of alkylphenols by gas chromatography, elution liquid chromatography, and gel permeation chromatography

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

Wittmann, S.; Decsy, Z.; Regensperger, S.

1984-01-01

The separation and determination of groups of alkylphenols with C/sub 15/-C/sub 33/ isoalkane chains by gas chromatography, elution liquid chromatography, and gel permeation chromatography are described. Paraffinic hydrocarbons, monoalkylphenols, dialkylphenols, and bis(hydroxyphenyl)alkanes were identified in industrial alkylphenols by mass spectrometry. 7 references, 3 figures, 2 tables.

Study of Separation and Identification of the Active Ingredients in Gardenia jasminoides Ellis Based on a Two-Dimensional Liquid Chromatography by Coupling Reversed Phase Liquid Chromatography and Hydrophilic Interaction Liquid Chromatography.

PubMed

Zhou, Xuan; Chen, Cen; Ye, Xiaolan; Song, Fenyun; Fan, Guorong; Wu, Fuhai

2017-01-01

In this paper, by coupling reversed phase liquid chromatography (RPLC) and hydrophilic interaction liquid chromatography (HILIC), a two-dimensional liquid chromatography system was developed for separation and identification of the active ingredients in Gardenia jasminoides Ellis (GJE). By applying the semi-preparative C18 column as the first dimension and the core-shell column as the second dimension, a total of 896 peaks of GJE were separated. Among the 896 peaks, 16 active ingredients including geniposide, gardenoside, gardoside, etc. were identified by mass spectrometry analysis. The results indicated that the proposed two-dimensional RPLC/HILIC system was an effective method for the analysis of GJE and might hold a high potential to become a useful tool for analysis of other complex mixtures. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Screening and analysis of the multiple absorbed bioactive components and metabolites in rat plasma after oral administration of Jitai tablets by high-performance liquid chromatography/diode-array detection coupled with electrospray ionization tandem mass spectrometry.

PubMed

Wang, Shu-Ping; Liu, Lei; Wang, Ling-Ling; Jiang, Peng; Zhang, Ji-Quan; Zhang, Wei-Dong; Liu, Run-Hui

2010-06-15

Based on the serum pharmacochemistry technique and high-performance liquid chromatography/diode-array detection (HPLC/DAD) coupled with electrospray tandem mass spectrometry (HPLC/ESI-MS/MS), a method for screening and analysis of the multiple absorbed bioactive components and metabolites of Jitai tablets (JTT) in orally dosed rat plasma was developed. Plasma was treated by methanol precipitation prior to liquid chromatography, and the separation was carried out on a Symmetry C(18) column, with a linear gradient (0.1% formic acid/water/acetonitrile). Mass spectra were acquired in negative and positive ion modes, respectively. As a result, 26 bioactive components originated from JTT and 5 metabolites were tentatively identified in orally dosed rat plasma by comparing their retention times and MS spectra with those of authentic standards and literature data. It is concluded that an effective and reliable analytical method was set up for screening the bioactive components of Chinese herbal medicine, which provided a meaningful basis for further pharmacology and active mechanism research of JTT. Copyright (c) 2010 John Wiley & Sons, Ltd.

Computational solvent system screening for the separation of tocopherols with centrifugal partition chromatography using deep eutectic solvent-based biphasic systems.

PubMed

Bezold, Franziska; Weinberger, Maria E; Minceva, Mirjana

2017-03-31

Tocopherols are a class of molecules with vitamin E activity. Among those, α-tocopherol is the most important vitamin E source in the human diet. The purification of tocopherols involving biphasic liquid systems can be challenging since these vitamins are poorly soluble in water. Deep eutectic solvents (DES) can be used to form water-free biphasic systems and have already proven applicable for centrifugal partition chromatography separations. In this work, a computational solvent system screening was performed using the predictive thermodynamic model COSMO-RS. Liquid-liquid equilibria of solvent systems composed of alkanes, alcohols and DES, as well as partition coefficients of α-tocopherol, β-tocopherol, γ-tocopherol, and σ-tocopherol in these biphasic solvent systems were calculated. From the results the best suited biphasic solvent system, namely heptane/ethanol/choline chloride-1,4-butanediol, was chosen and a batch injection of a tocopherol mixture, mainly consisting of α- and γ-tocopherol, was performed using a centrifugal partition chromatography set up (SCPE 250-BIO). A separation factor of 1.74 was achieved for α- and γ-tocopherol. Copyright © 2017 Elsevier B.V. All rights reserved.

Investigation of the Persistence of Nerve Agent Degradation ...

EPA Pesticide Factsheets

Journal Article The persistence of chemical warfare nerve agent degradation analytes on surfaces is important for reasons ranging from indicating the presence of nerve agent on that surface to environmental restoration of a site after nerve agent release. This study investigates the persistence of several chemical warfare nerve agent degradation analytes on a number of indoor surfaces and presents an approach for wipe sampling of surfaces, followed by wipe extraction and liquid chromatography-tandem mass spectrometry detection. Multiple commercially available wipe materials were investigated to determine optimal wipe recoveries. Tested surfaces, including several porous/permeable and largely nonporous/impermeable surfaces, were investigated to determine recoveries from these indoor surface materials. Wipe extracts were analyzed by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and compared with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) results. UPLC provides a sensitive separation of targeted degradation analytes in addition to being nearly four times faster than HPLC, allowing for greater throughput during a widespread release concerning large-scale contamination and subsequent remediation events. Percent recoveries from nonporous/impermeable surfaces were 60-103% for isopropyl methylphosphonate (IMPA), 61-91 % for ethyl methylphosphonate (EMPA), and 60-98% for pinacolyl methylphosphona

CHARACTERIZATION OF DANSYLATED CYSTEINE, CYSTINE, GLUTATHIONE, AND GLUTATHIONE DISULFIDE BY NARROW BORE LIQUID CHROMATOGRAPHY - ELECTROSPRAY IONIZATION MASS SPECTROMETRY

EPA Science Inventory

A method using reversed phase high performance liquid chromtography/electrospray ionization-mass spectrometry (RP-LC/ESI-MS) has been developed to confirm the dientity of dansylated derivatives of cysteine (C) and glutathione (GSH), and their respective dimers, cystine (CSSC) and...

ON-LINE DEOXYGENATION IN REDUCTIVE (AND OXIDATIVE) AMPEROMETRIC DETECTION: ENVIRONMENTAL APPLICATIONS IN THE LIQUID CHROMATOGRAPHY OF ORGANIC PEROXIDES

EPA Science Inventory

Cyclic voltammetry was used qualitatively to characterize and determine the feasibility of the oxidation and reduction of selected organic peroxides and hydroperoxides at a glassy carbon electrode. Organic peroxides were determined using reversed-phase high-performance liquid chr...

Improved procedure for determination of flucytosine in human blood plasma by high-pressure liquid chromatography.

PubMed Central

Schwertschlag, U; Nakata, L M; Gal, J

1984-01-01

Several high-pressure liquid chromatography procedures for the determination of flucytosine in serum or plasma have appeared. Some of these suffer from significant disadvantages, and none was applicable in our routine clinical therapeutic-drug-monitoring laboratory. A new high-pressure liquid chromatography assay for flucytosine was therefore developed. A 100-microliter sample of plasma was treated with an aqueous 5-iodocytosine internal-standard solution, and the mixture was deproteinized with trichloroacetic acid. A portion of the protein-free supernatant was diluted with 0.1 M ammonium phosphate, and an aliquot of the resulting solution was injected into the high-pressure liquid chromatography system. Chromatography was performed on a strong-cation-exchange column with a mobile phase containing aqueous ammonium phosphate, phosphoric acid, methanol, and acetonitrile. Detection was at 254 nm. The assay was shown to be linear in the 10 to 200-micrograms/ml drug-concentration range. Forty other drugs were tested for potential interference with the assay, and none was found. For routine use, a single-point working standard containing 75 micrograms of flucytosine per ml was used, giving intraassay coefficients of variation at 50 and 150 micrograms/ml of 1.8 and 2.3% respectively, whereas the day-to-day coefficient of variation at 50 micrograms/ml was 10.0%. Advantages of the procedure include the small sample size, the use of a convenient and reliable internal standard, speed, and simplicity. The assay is highly suitable for routine clinical drug-analysis laboratories. PMID:6508261

Investigation of folic acid stability in fortified instant noodles by use of capillary electrophoresis and reversed-phase high performance liquid chromatography.

PubMed

Hau Fung Cheung, Rodney; Morrison, Paul D; Small, Darryl M; Marriott, Philip J

2008-12-05

A single enzyme treatment with alpha-amylase, prior to the quantification of added folic acid (FA) in fortified instant fried Asian noodles with analysis performed by capillary zone electrophoresis (CZE) and reversed-phase high performance liquid chromatography (RP-HPLC) with UV detection, is described. The method was validated and optimized for capillary electrophoresis (CE) with separation achieved using a 8 mM phosphate-12 mM borate run buffer with 5% MeOH at pH 9.5. FA was well separated from matrix components with nicotinic acid (NA) employed as an internal standard. In a comparative study, separation of FA was performed using HPLC with a mobile phase consisting of 27% MeOH (v/v) in aqueous potassium phosphate buffer (3.5 mM KH(2)PO(4) and 3.2 mM K(2)HPO(4)), pH 8.5, and containing 5 mM tetrabutylammonium dihydrogen phosphate as an ion-pairing agent. For both methods, excellent results were obtained for various analytical parameters including linearity, accuracy and precision. The limit of detection was calculated to be 2.2 mg/L for CE without sample stacking and 0.10 mg/L with high performance liquid chromatography (HPLC). Sample extraction involved homogenization and enzymatic extraction with alpha-amylase. Results indicated that FA was stable during four main stages of instant fried noodle manufacturing (dough crumbs, cut sheets, steaming and frying).

Determination of type A trichothecenes in coix seed by magnetic solid-phase extraction based on magnetic multi-walled carbon nanotubes coupled with ultra-high performance liquid chromatography-tandem mass spectrometry.

PubMed

Dong, Maofeng; Si, Wenshuai; Wang, Weimin; Bai, Bing; Nie, Dongxia; Song, Weiguo; Zhao, Zhihui; Guo, Yirong; Han, Zheng

2016-09-01

Magnetic solid-phase extraction (m-SPE) is a promising sample preparation approach due to its convenience, speed, and simplicity. For the first time, a rapid and reliable m-SPE approach using magnetic multi-walled carbon nanotubes (m-MWCNTs) as the adsorbent was proposed for purification of type A trichothecenes including T-2 toxins (T2), HT-2 toxins (HT-2), diacetoxyscirpenol (DAS), and neosolaniol (NEO) in coix seed. The m-MWCNTs were synthesized by assembling the magnetic nanoparticles (Fe3O4) with MWCNTs by sonication through an aggregation wrap mechanism, and characterized by transmission electron microscope. Several key parameters affecting the performance of the procedure were extensively investigated including extraction solutions, desorption solvents, and m-MWCNT amounts. Under the optimal sample preparation conditions followed by analysis with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), high sensitivity (limit of quantification in the range of 0.3-1.5 μg kg(-1)), good linearity (R (2) > 0.99), satisfactory recovery (73.6-90.6 %), and acceptable precision (≤2.5 %) were obtained. The analytical performance of the developed method has also been successfully evaluated in real coix seed samples. Graphical Abstract Flow chart of determination of type A trichothecenes in coix seed by magnetic solid-phase extraction coupled with ultra-high performance liquid chromatography-tandem mass spectrometry.

Employment of High-Performance Thin-Layer Chromatography for the Quantification of Oleuropein in Olive Leaves and the Selection of a Suitable Solvent System for Its Isolation with Centrifugal Partition Chromatography.

PubMed

Boka, Vasiliki-Ioanna; Argyropoulou, Aikaterini; Gikas, Evangelos; Angelis, Apostolis; Aligiannis, Nektarios; Skaltsounis, Alexios-Leandros

2015-11-01

A high-performance thin-layer chromatographic methodology was developed and validated for the isolation and quantitative determination of oleuropein in two extracts of Olea europaea leaves. OLE_A was a crude acetone extract, while OLE_AA was its defatted residue. Initially, high-performance thin-layer chromatography was employed for the purification process of oleuropein with fast centrifugal partition chromatography, replacing high-performance liquid-chromatography, in the stage of the determination of the distribution coefficient and the retention volume. A densitometric method was developed for the determination of the distribution coefficients, KC = CS/CM. The total concentrations of the target compound in the stationary phase (CS) and in the mobile phase (CM) were calculated by the area measured in the high-performance thin-layer chromatogram. The estimated Kc was also used for the calculation of the retention volume, VR, with a chromatographic retention equation. The obtained data were successfully applied for the purification of oleuropein and the experimental results confirmed the theoretical predictions, indicating that high-performance thin-layer chromatography could be an important counterpart in the phytochemical study of natural products. The isolated oleuropein (purity > 95%) was subsequently used for the estimation of its content in each extract with a simple, sensitive and accurate high-performance thin-layer chromatography method. The best fit calibration curve from 1.0 µg/track to 6.0 µg/track of oleuropein was polynomial and the quantification was achieved by UV detection at λ 240 nm. The method was validated giving rise to an efficient and high-throughput procedure, with the relative standard deviation % of repeatability and intermediate precision not exceeding 4.9% and accuracy between 92% and 98% (recovery rates). Moreover, the method was validated for robustness, limit of quantitation, and limit of detection. The amount of oleuropein for OLE_A, OLE_AA, and an aqueous extract of olive leaves was estimated to be 35.5% ± 2.7, 51.5% ± 1.4, and 12.5% ± 0.12, respectively. Statistical analysis proved that the method is repeatable and selective, and can be effectively applied for the estimation of oleuropein in olive leaves' extracts, and could potentially replace high-performance liquid chromatography methodologies developed so far. Thus, the phytochemical investigation of oleuropein could be based on high-performance thin-layer chromatography coupled with separation processes, such as fast centrifugal partition chromatography, showing efficacy and credibility. Georg Thieme Verlag KG Stuttgart · New York.

Explosives Dissolved from Unexploded Ordnance

DTIC Science & Technology

2011-10-01

octahydro-1,3,5,7-tetranitrotetrazocine (often a bi- product of RDX production) HPLC High performance Liquid Chromatography IC Ion conductivity MMR...orange. Conductivity sensor 60-mm ordnance Nalgene bottle Water sample access 29 The water samples were analyzed with an ion chromatography ...Figure 41. Relationship between the ion conductivity measurements made on water samples and electrical conductivity measurements for one of

Endophytic Fungus from Sinopodophyllum emodi (Wall.) Ying that Produces Podophyllotoxin.

PubMed

Liang, Zizhen; Zhang, Jia; Zhang, Xuan; Li, Jinjie; Zhang, Xiaoqian; Zhao, Changqi

2016-02-01

The aryltetralin lactone podophyllotoxin, which exhibits pronounced antineoplastic activity, is used as the precursor of the following three clinical anticancer drugs: Etoposide™, Etopophos™ and Teniposide™. The natural occurrence of this arylnaphthalene lignan is scarce and unable to meet the ever-rising demand in the medical industry. Thus, developing alternative sources for the production of podophyllotoxin is extremely urgent. This is the first report of the production of podophyllotoxin from endophytic Alternaria tenuissima isolated from Sinopodophyllum emodi (Wall.) Ying. The identification of podophyllotoxin was performed using high-performance liquid chromatography and liquid chromatography-mass spectrometry (MS)-MS and confirmed by comparison with authentic standards. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Simultaneous determination of chloroquine and its three metabolites in human plasma, whole blood and urine by ion-pair high-performance liquid chromatography.

PubMed

Houzé, P; de Reynies, A; Baud, F J; Benatar, M F; Pays, M

1992-02-14

A method was developed for the separation and measurement of chloroquine and three metabolites (desethylchloroquine, bisdesethylchloroquine and 4-amino-7-chloroquinoline) in biological samples by ion-pair high-performance liquid chromatography with UV detection. The method uses 2,3-diaminoaphthalene as an internal standard and provides a limit of detection between 1 and 2 ng/ml for chloroquine and its metabolites. The assay was linear in the range 12.5-250 ng/ml and the analytical recovery and reproducibility were sufficient. The assay was applied to the analysis of biological samples from a patient undergoing chloroquine chemoprophylaxis and a patient who had ingested chloroquine in a suicide attempt.

Evaluation of antioxidant capacity and synergistic associations of quinonemethide triterpenes and phenolic substances from Maytenus ilicifolia (Celastraceae).

PubMed

Dos Santos, Vânia Aparecida de Freitas Formenton Macedo; Dos Santos, Daniela Pereira; Castro-Gamboa, Ian; Zanoni, Maria Valnice Boldrin; Furlan, Maysa

2010-10-11

This work describes the isolation of the secondary metabolites identified as the quinonemethides maytenin (1) and pristimerin (2) from Maytenus ilicifolia extracts obtained from root barks of adult plants and roots of seedlings and their quantification by high performance liquid chromatography coupled to a diode array detector. The electrochemical profiles obtained from cyclic voltammetry and a coulometric detector coupled to high-performance liquid chromatography contributed to the evaluation of their antioxidant capacity. The antioxidant properties of individual components and the crude extracts of the root barks of Maytenus ilicifolia were compared and the possible synergistic associations of quinonemethide triterpenes and phenolic substances were investigated by using rutin as a model phenolic compound.

[Determination of aspirin and free salicylic acid in lysinipirine injection by high performance liquid chromatography].

PubMed

Dong, Yu; Zhao, Yuan-zheng; Zhang, Yi-na

2002-05-01

The contents of aspirin and free salicylic acid in lysinipirine injection were determined by high performance liquid chromatography (HPLC). A Hypersil BDS C18 column was used with the mobile phase of methanol-water-acetic acid (35:65:3, volume ratio) and the detection wavelength of 280 nm. The average recoveries of aspirin and salicylic acid added were 99.27% (RSD = 0.8%) and 99.61%(RSD = 1.3%), respectively. The calibration curves had good linearity in the range of 0.028 g/L -0.141 mg/L and 0.77 mg/L -3.85 mg/L, and the correlation coefficients were 0.9999 and 0.9998 for aspirin and salicylic acid respectively.

Simultaneous quantification of five major active components in capsules of the traditional Chinese medicine ‘Shu-Jin-Zhi-Tong’ by high performance liquid chromatography

PubMed Central

Yang, Xing-Xin; Zhang, Xiao-Xia; Chang, Rui-Miao; Wang, Yan-Wei; Li, Xiao-Ni

2011-01-01

A simple and reliable high performance liquid chromatography (HPLC) method has been developed for the simultaneous quantification of five major bioactive components in ‘Shu-Jin-Zhi-Tong’ capsules (SJZTC), for the purposes of quality control of this commonly prescribed traditional Chinese medicine. Under the optimum conditions, excellent separation was achieved, and the assay was fully validated in terms of linearity, precision, repeatability, stability and accuracy. The validated method was applied successfully to the determination of the five compounds in SJZTC samples from different production batches. The HPLC method can be used as a valid analytical method to evaluate the intrinsic quality of SJZTC. PMID:29403711

Simultaneous determination of citrus limonoid aglycones and glucosides by high performance liquid chromatography.

PubMed

Vikram, Amit; Jayaprakasha, G K; Patil, Bhimanagouda S

2007-05-08

High performance liquid chromatography (HPLC) method has been developed for simultaneous quantification of limonoid aglycones and glucosides on a reversed phase C18 column using a binary solvent system, coupled with diode array detector. Seven limonoids such as limonin, nomilin, isolimonic acid, ichangin, isoobacunoic acid, limonin 17-beta-D glucopyranoside and deacetyl nomilinic acid 17-beta-D glucopyranoside were separated and detected at 210 nm. Furthermore, limonoids were separated, identified and quantified in four varieties of citrus fruits and seeds using developed method. Limonin and limonin glucoside were found to be the predominant limonoid aglycone and glucoside, respectively, in all tested samples. The sensitivity of the method was found to be 0.25-0.50 microg for tested limonoids.

Development and validation of a high performance liquid chromatography assay for 17alpha-methyltestosterone in fish feed.

PubMed

Marwah, Ashok; Marwah, Padma; Lardy, Henry

2005-09-25

17alpha-Methyltestosterone (MT) is used to manipulate the gender of a variety of fish species. A high performance liquid chromatography (HPLC) internal standard method for the determination of 17alpha-methyltestosterone in fish feed using 3beta-methoxy-17beta-hydroxyandrost-5-en-7-one as internal standard (IS) has been developed. The method has been validated for the quantitation of MT in fish feed using 245 nm UV absorbance as the parent wavelength and 255 nm as a qualifier wavelength. The method was validated in the concentration range of 15.0-120 mg/kg of 17alpha-methyltestosterone in fish feed. Method was also found to be suitable for other feeds.

Hydrocarbon group type determination in jet fuels by high performance liquid chromatography

NASA Technical Reports Server (NTRS)

Antoine, A. C.

1977-01-01

Results are given for the analysis of some jet and diesel fuel samples which were prepared from oil shale and coal syncrudes. Thirty-two samples of varying chemical composition and physical properties were obtained. Hydrocarbon types in these samples were determined by fluorescent indicator adsorption (FIA) analysis, and the results from three laboratories are presented and compared. Recently, rapid high performance liquid chromatography (HPLC) methods have been proposed for hydrocarbon group type analysis, with some suggestion for their use as a replacement of the FIA technique. Two of these methods were used to analyze some of the samples, and these results are also presented and compared. Two samples of petroleum-based Jet A fuel are similarly analyzed.

High-performance liquid chromatography measurement of hyperforin and its reduced derivatives in rodent plasma.

PubMed

Rozio, M; Fracasso, C; Riva, A; Morazzoni, P; Caccia, S

2005-02-25

A reverse-phase high-performance liquid chromatography method was developed for the determination of hyperforin and its reduced derivatives octahydrohyperforin and tetrahydrohyperforin in rodent plasma. The procedure includes solid-phase extraction from plasma using the Baker 3cc C8 cartridge, resolution on the Symmetry Shield RP8 column (150 mm x 4.6 mm, i.d. 3.5 microm) and UV absorbance detection at 300 nm. The assay was linear over a wide range, with an overall coefficient of variation less than 10% for all compounds. The precision and accuracy were within acceptable limits and the limit of quantitation was sufficient for studies preliminarily assessing the disposition of tetrahydrohyperforin and octahydrohyperforin in the mouse and rat.

[Determination of capsaicinoids and eugenol in waste-edible-oil by liquid-liquid extraction and liquid chromatography-tandem mass spectrometry].

PubMed

Zhang, Zhong; Ren, Fei; Zhang, Pan

2012-11-01

A method was developed for the determination of capsaicinoids (capsaicin, dihydrocapsaicin and synthetic capsaicin) and eugenol in waste-edible-oil extracted by liquid-liquid extraction and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The capsaicinoids and eugenol in waste-edible-oil were extracted by methanol, and then separated by a SUPEL COSIL ABZ + Plus dC18 column (150 mm x4.6 mm, 5 microm). The analysis was performed by MS/MS with electrospray ionization in positive and negative ion modes with multiple reaction monitoring (MRM). The limits of detection for capsaicin, dihydrocapsaicin, synthetic capsaicin and eugenol were 0.02, 0.03, 0.03 and 0.6 microg/L, respectively. The good linear relationships were obtained in certain concentration ranges of capsaicinoids and eugenol. The relative standard deviations (RSDs, n=5) of same-worker and different-worker were less than 5%. The method is exclusive, sensitive and accurate, and can be used in waste-edible-oil determination.

Analysis of potential migrants from plastic materials in milk by liquid chromatography-mass spectrometry with liquid-liquid extraction and low-temperature purification.

PubMed

Bodai, Zsolt; Szabó, Bálint Sámuel; Novák, Márton; Hámori, Susanne; Nyiri, Zoltán; Rikker, Tamás; Eke, Zsuzsanna

2014-10-15

A simple and fast analytical method was developed for the determination of six UV stabilizers (Cyasorb UV-1164, Tinuvin P, Tinuvin 234, Tinuvin 326, Tinuvin 327, and Tinuvin 1577) and five antioxidants (Irgafos 168, Irganox 1010, Irganox 3114, Irganox 3790, and Irganox 565) in milk. For sample preparation liquid-liquid extraction with low-temperature purification combined with centrifugation was used to remove fats, proteins, and sugars. After the cleanup step, the sample was analyzed with high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). External standard and matrix calibrations were tested. External calibration proved to be acceptable for Tinuvin P, Tinuvin 234, Tinuvin 326, Tinuvin 327, Irganox 3114, and Irganox 3790. The method was successfully validated with matrix calibration for all compounds. Method detection limits were between 0.25 and 10 μg/kg. Accuracies ranged from 93 to 109%, and intraday precisions were <13%.

A target and nontarget strategy for identification or characterization of the chemical ingredients in Chinese herb preparation Shuang-Huang-Lian oral liquid by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry.

PubMed

Zhang, Feng-Xiang; Li, Min; Yao, Zhi-Hong; Li, Chang; Qiao, Li-Rui; Shen, Xiu-Yu; Yu, Kate; Dai, Yi; Yao, Xin-Sheng

2018-03-01

A target and nontarget strategy based on in-house chemical components library was developed for rapid and comprehensive analysis of complicated components from traditional Chinese medicine preparation Shuang-Huang-Lian oral liquid. The sample was analyzed by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry using generic acquisition parameters. Automated detection and data filtering were performed on the UNIFI™ software and the detected peaks were evaluated against an in-house library. As a result, a total of 170 chemical components (110 target compounds and 60 nontarget ones) were identified or tentatively characterized, including 54 flavonoids, 30 phenylethanoid glycosides, 16 iridoid glycosides, 14 lignans, 32 organic acids, 19 triterpenoid saponins and five other types of compounds. Among them, 44 compounds were further confirmed by comparison with reference standards. It was demonstrated that this systematical approach could be successfully applied for rapid identification of multiple compounds in traditional Chinese medicine and its preparations. Furthermore, this work established the foundation for the further investigation on the metabolic fates of multiple ingredients in Shuang-Huang-Lian oral liquid. Copyright © 2017 John Wiley & Sons, Ltd.

Rapid analysis of ultraviolet filters using dispersive liquid-liquid microextraction coupled to headspace gas chromatography and mass spectrometry.

PubMed

Pierson, Stephen A; Trujillo-Rodríguez, María J; Anderson, Jared L

2018-05-29

An ionic-liquid-based in situ dispersive liquid-liquid microextraction method coupled to headspace gas chromatography and mass spectrometry was developed for the rapid analysis of ultraviolet filters. The chemical structures of five ionic liquids were specifically designed to incorporate various functional groups for the favorable extraction of the target analytes. Extraction parameters including ionic liquid mass, molar ratio of ionic liquid to metathesis reagent, vortex time, ionic strength, pH, and total sample volume were studied and optimized. The effect of the headspace temperature and volume during the headspace sampling step was also evaluated to increase the sensitivity of the method. The optimized procedure is fast as it only required ∼7-10 min per extraction and allowed for multiple extractions to be performed simultaneously. In addition, the method exhibited high precision, good linearity, and low limits of detection for six ultraviolet filters in aqueous samples. The developed method was applied to both pool and lake water samples attaining acceptable relative recovery values. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Matrix effect on the determination of synthetic corticosteroids and diuretics by liquid chromatography-tandem mass spectrometry

NASA Astrophysics Data System (ADS)

Dikunets, M. A.; Appolonova, S. A.; Rodchenkov, G. M.

2009-04-01

This work presents a high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) procedure for selective and reliable screening of corticosteroids and diuretics in human urine. Sample preparation included the extraction, evaporation of the organic extract under nitrogen, and solution of the dry residue. The extract was analyzed by HPLC combined with tandem mass spectrometry using electro-spraying ionization at atmospheric pressure with negative ion recording. The mass spectra of all compounds were recorded, and the characteristic ions, retention times, and detection limits were determined. The procedure was validated by evaluating the degree of the matrix suppression of ionization, extraction of analytes from human biological liquid, and the selectivity and specificity of determination.

Automated High-Performance Liquid Chromatography Saturate, Aromatic, Resin, and Asphaltene Separation

DOT National Transportation Integrated Search

2016-10-01

Dividing a material into its constituent parts is necessary to define its composition. These compositional analyses are useful in binder formulation through blending, rejuvenation, and modification, as well as prediction of physical performance. Norm...

N-linked glycoprotein analysis using dual-extraction ultrahigh-performance liquid chromatography and electrospray tandem mass spectrometry.

PubMed

Siu, S O; Lam, Maggie P Y; Lau, Edward; Yeung, William S B; Cox, David M; Chu, Ivan K

2010-01-01

Although reverse-phase liquid chromatography (RP-LC) is a common technique for peptide separation in shotgun proteomics and glycoproteomics, it often provides unsatisfactory results for the analysis of glycopeptides and glycans. This bias against glycopeptides makes it difficult to study glycoproteins. By coupling mass spectrometry (MS) with a combination of RP-LC and normal-phase (NP)-LC as an integrated front-end separation system, we demonstrate that effective identification and characterization of both peptides and glycopeptides mixtures, and their constituent glycan structures, can be achieved from a single sample injection event.

[Simultaneous analysis of aromatic aldehydes and coumarins with high pressure liquid chromatography. Application to wines and brandies stored in oak barrels].

PubMed

Salagoity-Auguste, M H; Tricard, C; Sudraud, P

1987-04-17

Aromatic aldehydes (vanillin, syringaldehyde, coniferaldehyde and sinapaldehyde) and coumarins (esculetin, umbelliferone, scopoletin and methylumbelliferone) are natural wood compounds. Storage of wines and brandies in oak barrels increases notably aldehydes and coumarins (particularly scopoletin) concentrations. These compounds were separated by high-performance liquid chromatography, on hydrocarbon bonded reversed-phase packings, with a water-acetonitrile elution gradient. They were first extracted from wines and brandies by diethyl ether and then injected on chromatographic column. A double detection was used to determine simultaneously aromatic aldehydes and coumarins by UV absorption and fluorescence respectively.

Simultaneous determination of 19 flavonoids in commercial trollflowers by using high-performance liquid chromatography and classification of samples by hierarchical clustering analysis.

PubMed

Song, Zhiling; Hashi, Yuki; Sun, Hongyang; Liang, Yi; Lan, Yuexiang; Wang, Hong; Chen, Shizhong

2013-12-01

The flowers of Trollius species, named Jin Lianhua in Chinese, are widely used traditional Chinese herbs with vital biological activity that has been used for several decades in China to treat upper respiratory infections, pharyngitis, tonsillitis, and bronchitis. We developed a rapid and reliable method for simultaneous quantitative analysis of 19 flavonoids in trollflowers by using high-performance liquid chromatography (HPLC). Chromatography was performed on Inertsil ODS-3 C18 column, with gradient elution methanol-acetonitrile-water with 0.02% (v/v) formic acid. Content determination was used to evaluate the quality of commercial trollflowers from different regions in China, while three Trollius species (Trollius chinensis Bunge, Trollius ledebouri Reichb, Trollius buddae Schipcz) were explicitly distinguished by using hierarchical clustering analysis. The linearity, precision, accuracy, limit of detection, and limit of quantification were validated for the quantification method, which proved sensitive, accurate and reproducible indicating that the proposed approach was applicable for the routine analysis and quality control of trollflowers. © 2013.

Rapid analysis of N-linked oligosaccharides in glycoproteins (ovalbumin, ribonuclease B and fetuin) by reversed-phase ultra-performance liquid chromatography with fluorescence detection and electrospray ionization time-of-flight mass spectrometry.

PubMed

Kurihara, Takamasa; Min, Jun Zhe; Hirata, Asuka; Toyo'oka, Toshimasa; Inagaki, Shinsuke

2009-05-01

Rapid, selective and sensitive determination of N-linked oligosaccharides in glycoproteins (ovalbumin, ribonuclease B and fetuin) was performed by ultra-performance liquid chromatography (UPLC) with fluorescence (FL) and electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS). The asparaginyl-oligosaccharide moiety was first liberated from each glycoprotein by pronase E (a proteolitic enzyme). The oligosaccharide fractions separated by gel-permeation chromatography were labeled with 1-pyrenesulfonyl chloride (PSC, a fluorescence reagent), separated by UPLC in a short run time, and then detected by FL and TOF-MS. The PSC-labeled oligosaccharides were selectively identified from the FL detection and then sensitively determined by ESI-TOF-MS. As the results, 15, eight and four kinds of N-linked oligosaccharides were detected from ovalbumin, ribonuclease B and fetuin, respectively. Because the present method is rapid (within 9 min), selective and sensitive (approximate 60 fmol, S/N = 5), the determination of N-linked oligosaccharides in various glycoproteins seems to be possible.

Comparison of large scale purification processes of naproxen enantiomers by chromatography using methanol-water and methanol-supercritical carbon dioxide mobile phases.

PubMed

Kamarei, Fahimeh; Vajda, Péter; Guiochon, Georges

2013-09-20

This paper compares two methods used for the preparative purification of a mixture of (S)-, and (R)-naproxen on a Whelk-O1 column, using either high performance liquid chromatography or supercritical fluid chromatography. The adsorption properties of both enantiomers were measured by frontal analysis, using methanol-water and methanol-supercritical carbon dioxide mixtures as the mobile phases. The measured adsorption data were modeled, providing the adsorption isotherms and their parameters, which were derived from the nonlinear fit of the isotherm models to the experimental data points. The model used was a Bi-Langmuir isotherm, similar to the model used in many enantiomeric separations. These isotherms were used to calculate the elution profiles of overloaded elution bands, assuming competitive Bi-Langmuir behavior of the two enantiomers. The analysis of these profiles provides the basis for a comparison between supercritical fluid chromatographic and high performance liquid chromatographic preparative scale separations. It permits an illustration of the advantages and disadvantages of these methods and a discussion of their potential performance. Copyright © 2013 Elsevier B.V. All rights reserved.

[Determination of arbutin in apple juice concentrate by ultra performance liquid chromatography with electrospray ionization tandem mass spectrometry].

PubMed

Kong, Xianghong; He, Qiang; Yue, Aishan; Wu, Shuangmin; Li, Jianhua

2010-06-01

An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/ MS) method was developed for the determination of arbutin in apple juice concentrate. Samples were diluted with water, then cleaned-up with a PS-DVB column. Quantitation was carried out using an external standard method. UPLC was performed on an Eclipse Plus C, column (100 mm x 2.1 mm, 1.8 microm) using a gradient solvent system (methanol-water). MS/MS was performed with multiple reaction monitoring (MRM) mode. The detection limit of arbutin was 0.02 mg/L. The method showed good linear relationship at the range of 0.04-2.0 mg/L. The recoveries ranged from 75.2% to 102.7% with relative standard deviations (RSDs) less than 8.9%. The method is simple, fast and sensitive. It's suitable for quantitative and qualitative analysis of arbutin in apple juice concentrate.

Nonesterified fatty acid determination for functional lipidomics: comprehensive ultrahigh performance liquid chromatography-tandem mass spectrometry quantitation, qualification, and parameter prediction.

PubMed

Hellmuth, Christian; Weber, Martina; Koletzko, Berthold; Peissner, Wolfgang

2012-02-07

Despite their central importance for lipid metabolism, straightforward quantitative methods for determination of nonesterified fatty acid (NEFA) species are still missing. The protocol presented here provides unbiased quantitation of plasma NEFA species by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Simple deproteination of plasma in organic solvent solution yields high accuracy, including both the unbound and initially protein-bound fractions, while avoiding interferences from hydrolysis of esterified fatty acids from other lipid classes. Sample preparation is fast and nonexpensive, hence well suited for automation and high-throughput applications. Separation of isotopologic NEFA is achieved using ultrahigh-performance liquid chromatography (UPLC) coupled to triple quadrupole LC-MS/MS detection. In combination with automated liquid handling, total assay time per sample is less than 15 min. The analytical spectrum extends beyond readily available NEFA standard compounds by a regression model predicting all the relevant analytical parameters (retention time, ion path settings, and response factor) of NEFA species based on chain length and number of double bonds. Detection of 50 NEFA species and accurate quantification of 36 NEFA species in human plasma is described, the highest numbers ever reported for a LC-MS application. Accuracy and precision are within widely accepted limits. The use of qualifier ions supports unequivocal analyte verification. © 2012 American Chemical Society

Thin-layer chromatography coupled with high performance liquid chromatography for determining tetrabromobisphenol A/S and their derivatives in soils.

PubMed

Liu, Aifeng; Shen, Zhaoshuang; Tian, Yong; Shi, Rongguang; Liu, Yi; Zhao, Zongshan; Xian, Mo

2017-12-01

As brominated flame retardants (BFRs), tetrabromobisphenol A/S (TBBPA/S) and their derivatives have raised wide concerns owing to their widely usage, distributions and adverse effects on human health, thus monitoring these BFRs was urgently needed. In this study, a rapid and cost-effective method based on thin-layer chromatography (TLC) sample pre-treatment coupled with high performance liquid chromatography-diode array detector (HPLC-DAD) (UV=214nm) was developed for determining TBBPA/S and their derivatives in soils, including TBBPA, TBBPA bis(allyl ether) (TBBPA-BAE), TBBPA bis(2,3-dibromopropyl ether) (TBBPA-BDBPE), TBBPS bis(allyl ether) (TBBPS-BAE) and TBBPS bis(2,3-dibromopropyl ether) (TBBPS-BDBPE). The method detection limits (MDLs) and the method quantification limits (MQLs) for these BFRs ranged from 0.023 to 0.087μgg -1 dw and 0.076-0.29μgg -1 dw, respectively. The recoveries were 41-108% and both RSD of repeatability and intermediate precision were less than 11%. The developed method presented good performance for analyzing natural soil samples collected from BFRs industrial park, suggesting its great application potential for monitoring environmental TBBPA/S and their derivatives. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization of peak capacity of microbore liquid chromatography columns using gradient kinetic plots.

PubMed

Hetzel, Terence; Blaesing, Christina; Jaeger, Martin; Teutenberg, Thorsten; Schmidt, Torsten C

2017-02-17

The performance of micro-liquid chromatography columns with an inner diameter of 0.3mm was investigated on a dedicated micro-LC system for gradient elution. Core-shell as well as fully porous particle packed columns were compared on the basis of peak capacity and gradient kinetic plot limits. The results for peak capacity showed the superior performance of columns packed with sub-2μm fully porous particles compared to 3.0μm fully porous and 2.7μm core-shell particles within a range of different gradient time to column void time ratios. For ultra-fast chromatography a maximum peak capacity of 16 can be obtained using a 30s gradient for the sub-2μm fully porous particle packed column. A maximum peak capacity of 121 can be achieved using a 5min gradient. In addition, the influence of an alternative detector cell on the basis of optical waveguide technology and contributing less to system variance was investigated showing an increased peak capacity for all applied gradient time/column void time ratios. Finally, the influence of pressure was evaluated indicating increased peak capacity for maximum performance whereas a limited benefit for ultra-fast chromatography with gradient times below 30s was observed. Copyright © 2017 Elsevier B.V. All rights reserved.

Liquid chromatography/mass spectrometry and liquid chromatography/nuclear magnetic resonance as complementary analytical techniques for unambiguous identification of polymethoxylated flavones in residues from molecular distillation of orange peel oils (Citrus sinensis).

PubMed

Weber, Berthold; Hartmann, Beate; Stöckigt, Detlef; Schreiber, Klaus; Roloff, Michael; Bertram, Heinz-Jürgen; Schmidt, Claus O

2006-01-25

Liquid chromatography/mass spectrometry and liquid chromatography/nuclear magnetic resonance techniques with ultraviolet/diode array detection were used as complementary analytical tools for the reliable identification of polymethoxylated flavones in residues from molecular distillation of cold-pressed peel oils of Citrus sinensis. After development of a liquid chromatographic separation procedure, the presence of several polymethoxy flavones such as sinensetin, nobiletin, tangeretin, quercetogetin, heptamethoxyflavone, and other derivatives was unambiguously confirmed. In addition, proceranone, an acetylated tetranortriterpenoid with limonoid structure, was identified for the first time in citrus.

Determination of triazine herbicides in juice samples by microwave-assisted ionic liquid/ionic liquid dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography.

PubMed

Su, Rui; Li, Dan; Wu, Lijie; Han, Jing; Lian, Wenhui; Wang, Keren; Yang, Hongmei

2017-07-01

A novel microextraction method, termed microwave-assisted ionic liquid/ionic liquid dispersive liquid-liquid microextraction, has been developed for the rapid enrichment and analysis of triazine herbicides in fruit juice samples by high-performance liquid chromatography. Instead of using hazardous organic solvents, two kinds of ionic liquids, a hydrophobic ionic liquid (1-hexyl-3-methylimidazolium hexafluorophosphate) and a hydrophilic ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate), were used as the extraction solvent and dispersion agent, respectively, in this method. The extraction procedure was induced by the formation of cloudy solution, which was composed of fine drops of 1-hexyl-3-methylimidazolium hexafluorophosphate dispersed entirely into sample solution with the help of 1-butyl-3-methylimidazolium tetrafluoroborate. In addition, an ion-pairing agent (NH 4 PF 6 ) was introduced to improve recoveries of the ionic liquid phase. Several experimental parameters that might affect the extraction efficiency were investigated. Under the optimum experimental conditions, the linearity for determining the analytes was in the range of 5.00-250.00 μg/L, with the correlation coefficients of 0.9982-0.9997. The practical application of this effective and green method is demonstrated by the successful analysis of triazine herbicides in four juice samples, with satisfactory recoveries (76.7-105.7%) and relative standard deviations (lower than 6.6%). In general, this method is fast, effective, and robust to determine triazine herbicides in juice samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Systematic Comparison of Reverse Phase and Hydrophilic Interaction Liquid Chromatography Platforms for the Analysis of N-linked Glycans

PubMed Central

Walker, S. Hunter; Carlisle, Brandon C.; Muddiman, David C.

2013-01-01

Due to the hydrophilic nature of glycans, reverse phase chromatography has not been widely used as a glycomic separation technique coupled to mass spectrometry. Other approaches such as hydrophilic interaction chromatography and porous graphitized carbon chromatography are often employed, though these strategies frequently suffer from decreased chromatographic resolution, long equilibration times, indefinite retention, and column bleed. Herein, it is shown that through an efficient hydrazone formation derivatization of N-linked glycans (∼4 hr of additional sample preparation time which is carried out in parallel), numerous experimental and practical advantages are gained when analyzing the glycans by online reverse phase chromatography. These benefits include an increased number of glycans detected, increased peak capacity of the separation, and the ability to analyze glycans on the identical liquid chromatography-mass spectrometry platform commonly used for proteomic analyses. The data presented show that separation of derivatized N-linked glycans by reverse phase chromatography significantly out-performs traditional separation of native or derivatized glycans by hydrophilic interaction chromatography. Furthermore, the movement to a more ubiquitous separation technique will afford numerous research groups the opportunity to analyze both proteomic and glycomic samples on the same platform with minimal time and physical change between experiments, increasing the efficiency of ‘multi-omic’ biological approaches. PMID:22954204

Comprehensive comparison of liquid chromatography selectivity as provided by two types of liquid chromatography detectors (high resolution mass spectrometry and tandem mass spectrometry): "where is the crossover point?".

PubMed

Kaufmann, A; Butcher, P; Maden, K; Walker, S; Widmer, M

2010-07-12

The selectivity of mass traces obtained by monitoring liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS) and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was compared. A number of blank extracts (fish, pork kidney, pork liver and honey) were separated by ultra performance liquid chromatography (UPLC). Detected were some 100 dummy transitions respectively dummy exact masses (traces). These dummy masses were the product of a random generator. The range of the permitted masses corresponded to those which are typical for analytes (e.g. veterinary drugs). The large number of monitored dummy traces ensured that endogenous compounds present in the matrix extract, produced a significant number of detectable chromatographic peaks. All obtained chromatographic peaks were integrated and standardized. Standardisation was done by dividing these absolute peak areas by the average response of a set of 7 different veterinary drugs. This permitted a direct comparison between the LC-HRMS and LC-MS/MS data. The data indicated that the selectivity of LC-HRMS exceeds LC-MS/MS, if high resolution mass spectrometry (HRMS) data is recorded with a resolution of 50,000 full width at half maximum (FWHM) and a corresponding mass window. This conclusion was further supported by experimental data (MS/MS based trace analysis), where a false positive finding was observed. An endogenous matrix compound present in honey matrix behaved like a banned nitroimidazole drug. This included identical retention time and two MRM traces, producing an MRM ratio between them, which perfectly matched the ratio observed in the external standard. HRMS measurement clearly resolved the interfering matrix compound and unmasked the false positive MS/MS finding. Copyright 2010 Elsevier B.V. All rights reserved.

Optimization and validation of liquid chromatography and headspace-gas chromatography based methods for the quantitative determination of capsaicinoids, salicylic acid, glycol monosalicylate, methyl salicylate, ethyl salicylate, camphor and l-menthol in a topical formulation.

PubMed

Pauwels, Jochen; D'Autry, Ward; Van den Bossche, Larissa; Dewever, Cédric; Forier, Michel; Vandenwaeyenberg, Stephanie; Wolfs, Kris; Hoogmartens, Jos; Van Schepdael, Ann; Adams, Erwin

2012-02-23

Capsaicinoids, salicylic acid, methyl and ethyl salicylate, glycol monosalicylate, camphor and l-menthol are widely used in topical formulations to relieve local pain. For each separate compound or simple mixtures, quantitative analysis methods are reported. However, for a mixture containing all above mentioned active compounds, no assay methods were found. Due to the differing physicochemical characteristics, two methods were developed and optimized simultaneously. The non-volatile capsaicinoids, salicylic acid and glycol monosalicylate were analyzed with liquid chromatography following liquid-liquid extraction, whereas the volatile compounds were analyzed with static headspace-gas chromatography. For the latter method, liquid paraffin was selected as compatible dilution solvent. The optimized methods were validated in terms of specificity, linearity, accuracy and precision in a range of 80% to 120% of the expected concentrations. For both methods, peaks were well separated without interference of other compounds. Linear relationships were demonstrated with R² values higher than 0.996 for all compounds. Accuracy was assessed by performing replicate recovery experiments with spiked blank samples. Mean recovery values were all between 98% and 102%. Precision was checked at three levels: system repeatability, method precision and intermediate precision. Both methods were found to be acceptably precise at all three levels. Finally, the method was successfully applied to the analysis of some real samples (cutaneous sticks). Copyright © 2011 Elsevier B.V. All rights reserved.

Ionic liquid foam floatation coupled with solid phase extraction for separation and determination of hormones by high-performance liquid chromatography.

PubMed

Zhang, Rui; Li, Na; Wang, Chuanliu; Bai, Yuping; Ren, Ruibing; Gao, Shiqian; Yu, Wenzhi; Zhao, Tianqi; Zhang, Hanqi

2011-10-17

The foaming property of ionic liquids (ILs) was found and the factors that can influence foamability of the ILs were investigated. Based on the property of the ILs, the foam floatation-solid phase extraction (FF-SPE) was developed. The IL-based FF-SPE was applied to the extraction and concentration of steroid hormones, including corticosterone, 17-β-estadiol, 17-α-estradiol, 19-nortestosterone, estrone, testosterone, 17-α-hydroxyprogesterone, medroxyprogesterone, chloromadinon 17-acetate, norethisterone acetate, medroxyprogesterone-17-acetate, progesterone, 17-β-estradiol 3-benzoate and testosteron 17-propionate in water samples and then the steroid hormones were determined by high-performance liquid chromatography. The extraction and concentration were performed synchronously in 10 min. Some experimental conditions were examined and optimized. The recoveries ranged from 50.6% to 95.2% for lake water sample and from 53.4% to 98.7% for rain water sample. The precision ranged from 2.43% to 7.43% for the lake water sample and 2.07-7.01% for rain water sample. Based on the foaming property of ILs, the application of foam floatation should be widened. Copyright © 2011 Elsevier B.V. All rights reserved.

Development of a perfusion reversed-phase high performance liquid chromatography method for the characterisation of maize products using multivariate analysis.

PubMed

Rodriguez-Nogales, J M; Garcia, M C; Marina, M L

2006-02-03

A perfusion reversed-phase high performance liquid chromatography (RP-HPLC) method has been designed to allow rapid (3.4 min) separations of maize proteins with high resolution. Several factors, such as extraction conditions, temperature, detection wavelength and type and concentration of ion-pairing agent were optimised. A fine optimisation of the gradient elution was also performed by applying experimental design. Commercial maize products for human consumption (flours, precocked flours, fried snacks and extruded snacks) were characterised for the first time by perfusion RP-HPLC and their chromatographic profiles allowed a differentiation among products relating the different technological process used for their preparation. Furthermore, applying discriminant analysis makes it possible to group the samples according with the technological process suffered by maize products, obtaining a good prediction in 92% of the samples.

Quality control of modified xiaoyao san through the determination of 22 active components by ultra-performance liquid chromatography.

PubMed

Qin, Feng; Huang, Jun; Qiu, Xinjian; Hu, Sihang; Huang, Xi

2011-01-01

A simple, sensitive, and reliable ultra-performance liquid chromatography (UPLC) method has been developed for simultaneous determination of 22 major constituents in modified xiaoyao san (MXS), a multiherbal formula. The chromatographic separation was performed on an ACQUITY UPLC BEH C18 column (150 x 2.1 mm, 1.7 microm, particle size), with an aqueous 0.5% acetic acid and acetonitrile mobile phase gradient. The method was validated for linearity (r2 >0.9937), intraday and interday precision (RSD <8.51%), recovery (91.18-107.73%), LOD (0.02-4.17 ng/mL), and LOQ (0.05-12.50 ng/mL). The established method was successfully applied to quantify the 22 marker compounds in MXS, which provided a useful basis of overall evaluation of the quality of MXS.

Validation of a method for simultaneous determination of nitroimidazoles, benzimidazoles and chloramphenicols in swine tissues by ultra-high performance liquid chromatography-tandem mass spectrometry.

PubMed

Xia, Xi; Wang, Yuanyuan; Wang, Xia; Li, Yun; Zhong, Feng; Li, Xiaowei; Huang, Yaoling; Ding, Shuangyang; Shen, Jianzhong

2013-05-31

This paper presents a sensitive and confirmatory multi-residue method for the analysis of 23 veterinary drugs and metabolites belonging to three classes (nitroimidazoles, benzimidazoles, and chloramphenicols) in porcine muscle, liver, and kidney. After extracted with ethyl acetate and basic ethyl acetate sequentially, the crude extracts were defatted with hexane and further purified using Oasis MCX solid-phase extraction cartridges. Rapid determination was carried out by ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometry. Data acquisition was performed under positive and negative mode simultaneously. Recoveries based on matrix-matched calibrations for meat, liver, and kidney ranged from 50.6 to 108.1%. The method quantification limits were in the range of 3-100ng/kg. Copyright © 2012 Elsevier B.V. All rights reserved.

Gas and liquid chromatography with inductively coupled plasma mass spectrometry detection for environmental speciation analysis — advances and limitations

NASA Astrophysics Data System (ADS)

Szpunar, Joanna; McSheehy, Shona; Połeć, Kasia; Vacchina, Véronique; Mounicou, Sandra; Rodriguez, Isaac; Łobiński, Ryszard

2000-07-01

Recent advances in the coupling of gas chromatography (GC) and high performance liquid chromatography (HPLC) with inductively coupled plasma mass spectrometry (ICP MS) and their role in trace element speciation analysis of environmental materials are presented. The discussion is illustrated with three research examples concerning the following topics: (i) development and coupling of multicapillary microcolumn GC with ICP MS for speciation of organotin in sediment and biological tissue samples; (ii) speciation of arsenic in marine algae by size-exclusion-anion-exchange HPLC-ICP MS; and (iii) speciation of cadmium in plant cell cultures by size-exclusion HPLC-ICP MS. Particular attention is paid to the problem of signal identification in ICP MS chromatograms; the potential of electrospray MS/MS for this purpose is highlighted.

Analysis of phospholipids in bio-oils and fats by hydrophilic interaction liquid chromatography-tandem mass spectrometry.

PubMed

Viidanoja, Jyrki

2015-09-15

A new, sensitive and selective liquid chromatography-electrospray ionization-tandem mass spectrometric (LC-ESI-MS/MS) method was developed for the analysis of Phospholipids (PLs) in bio-oils and fats. This analysis employs hydrophilic interaction liquid chromatography-scheduled multiple reaction monitoring (HILIC-sMRM) with a ZIC-cHILIC column. Eight PL class selective internal standards (homologs) were used for the semi-quantification of 14 PL classes for the first time. More than 400 scheduled MRMs were used for the measurement of PLs with a run time of 34min. The method's performance was evaluated for vegetable oil, animal fat and algae oil. The averaged within-run precision and between-run precision were ≤10% for all of the PL classes that had a direct homologue as an internal standard. The method accuracy was generally within 80-120% for the tested PL analytes in all three sample matrices. Copyright © 2015 Elsevier B.V. All rights reserved.

High-pressure liquid chromatography with direct injection of gas sample.

PubMed

Astanin, Anton I; Baram, Grigory I

2017-06-09

The conventional method of using liquid chromatography to determine the composition of a gaseous mixture entails dissolving vapors in a suitable solvent, then obtaining a chromatograph of the resulting solution. We studied the direct introduction of a gaseous sample into a C18 reversed-phase column, followed by separation of the components by HPLC with UV detection. Since the chromatography was performed at high pressure, vapors readily dissolved in the eluent and the substances separated in the column as effectively as in liquid samples. Samples were injected into the column in two ways: a) through the valve without a flow stop; b) after stopping the flow and relieving all pressure. We showed that an injectable gas volume could reach 70% of column dead volume. When an injected gaseous sample volume was less than 10% of the column dead volume, the resulting peaks were symmetrical and the column efficiency was high. Copyright © 2017 Elsevier B.V. All rights reserved.

Contemporary carbon content of bis (2-ethylhexyl) phthalate in butter.

PubMed

Tong, T; Ondov, J M; Buchholz, B A; VanDerveer, M C

2016-01-01

The fraction of naturally produced bis (2-ethylhexyl) phthalate (DEHP), a ubiquitous plasticizer known to contaminate packaged foods, was determined for each of five 1.10 kg samples of unsalted market butter by accelerator mass spectrometry (AMS). After extraction and concentration enrichment with liquid-liquid extraction, flash column chromatography, and preparative-scale high performance liquid chromatography, each sample provided ≈ 250 μg extracts of DEHP with carbon purity ranging from 92.5 ± 1.2% (n = 3, 1σ) to 97.1 ± 0.8% (n = 3, 1σ) as measured with gas chromatography mass spectrometry (GC-MS). After corrections for method blank DEHP, co-eluting compounds, and unidentified carbon, the mean fraction of naturally produced DEHP in butter was determined to be 0.16 ± 0.12 (n = 5, 1σ). To our knowledge, this is the first report of the contemporary fraction of DEHP isolated from market butter in the U.S. Copyright © 2015 Elsevier Ltd. All rights reserved.

Demonstration and Evaluation of Solid Phase Microextraction for the Assessment of Bioavailability and Contaminant Mobility. ESTCP Cost and Performance Report

DTIC Science & Technology

2012-08-01

subsequent chemical analysis (into acetonitrile for high-performance liquid chromatography [ HPLC ] analysis or hexane for gas chromatography [GC... analysis ) is rapid and complete. In this work, PAHs were analyzed by Waters 2795 HPLC with fluorescent detection (USEPA Method 8310) and PCBs were...detection limits by direct water injection versus SPME with PDMS and coefficient of variation and correlation coefficient for SPME. Analysis by HPLC

Degradation of 2,4,6-trinitrotoluene by P. aeruginosa and characterization of some metabolites.

PubMed

Mercimek, Hatice Aysun; Dincer, Sadik; Guzeldag, Gulcihan; Ozsavli, Aysenur; Matyar, Fatih; Arkut, Afet; Kayis, Fikret; Ozdenefe, Melis Sumengen

2015-03-01

Degradation of 2,4,6-trinitrotoluene (TNT), a nitroaromatic explosive found in the soil and ground water, was investigated using Pseudomonas aeruginosa in in vitro experiments . Biodegradable abilitiy of this bacteria was performed with 50 and 75 mg L (-1) TNT concentrations in a defined liquid medium for 96 h time period. Treatment of TNT in supernatant samples taken at 0, 6, 12, 24, 48, 72 and 96 h from agitated vessels was followed by reverse-phase high-performance liquid chromatography (HPLC). In cultures supplemented with 50 and 75 mgL (-1) TNT, after 96 h of incubation 46% and 59% reduction were detected respectively. Two metabolites as degradation intermediates with nitrite release into the medium, 2,4-dinitrotoluene (2,4-DNT) and 4-aminodinitrotoluene (4-ADNT), were elucidated by thin layer chromatography (TLC) and gas chromatography-mass spectrometry (GC-MS). These findings clearly indicate that Pseudomonas aeruginosa can be used in bioremediation of TNT contaminated sites.

Degradation of 2,4,6-trinitrotoluene by P. aeruginosa and characterization of some metabolites

PubMed Central

Mercimek, Hatice Aysun; Dincer, Sadik; Guzeldag, Gulcihan; Ozsavli, Aysenur; Matyar, Fatih; Arkut, Afet; Kayis, Fikret; Ozdenefe, Melis Sumengen

2015-01-01

Degradation of 2,4,6-trinitrotoluene (TNT), a nitroaromatic explosive found in the soil and ground water, was investigated using Pseudomonas aeruginosa in in vitro experiments . Biodegradable abilitiy of this bacteria was performed with 50 and 75 mg L −1 TNT concentrations in a defined liquid medium for 96 h time period. Treatment of TNT in supernatant samples taken at 0, 6, 12, 24, 48, 72 and 96 h from agitated vessels was followed by reverse-phase high-performance liquid chromatography (HPLC). In cultures supplemented with 50 and 75 mgL −1 TNT, after 96 h of incubation 46% and 59% reduction were detected respectively. Two metabolites as degradation intermediates with nitrite release into the medium, 2,4-dinitrotoluene (2,4-DNT) and 4-aminodinitrotoluene (4-ADNT), were elucidated by thin layer chromatography (TLC) and gas chromatography-mass spectrometry (GC-MS). These findings clearly indicate that Pseudomonas aeruginosa can be used in bioremediation of TNT contaminated sites. PMID:26221094

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.