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Three-phase hollow-fiber liquid-phase microextraction combined with HPLC-UV for the determination of isothiazolinone biocides in adhesives used for food packaging materials

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JOURNAL OF SEPARATION SCIENCE 2014年第3期37卷 272-280页

作者： Rosero-Moreano, Milton Canellas, Elena Nerin, Cristina Univ Zaragoza Inst Invest Ingn Aragon I3A Dept Quim Anal Zaragoza 50018 Spain Univ Caldas Dept Quim Manizales Caldas Colombia SAMTACK Adhes Ind Barcelona Spain

The present study deals with the development of a liquid microextraction procedure for enhancing the sensitivity of the determination of 2-methyl-4-isothiazolin-3-one and 5-chloro-2methyl-4-isothiazolin-3-one in adhesives. The procedure involves a three-phase hollow-fiber liquid-phase microextraction using a semipermeable polypropylene membrane, which contained 1-octanol as the organic phase in the pores of the membrane. The donor and acceptor phases are aqueous acidic and alkaline media, respectively, and the final liquid phase (acceptor) is analyzed by HPLC coupled with diode array detection. The most appropriate conditions were extraction time 20 min, stirring speed 1400 rpm, extraction temperature 50 degrees C. The quantification limits of the method were 0.123 and 0.490 mu g/g for 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one, respectively. Three different adhesive samples were successfully analyzed. The procedure was compared to direct analysis using ultra high pressure liquid chromatography coupled with TOF-MS, where the identification of the compounds and the quantification values were confirmed.

关键词： Adhesives diode array detection Food packaging Hollow-fiber microextraction Isothiazolones

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

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TALANTA 2014年第0期121卷 194-198页

作者： Rodriguez-Gonzalez, N. Gonzalez-Castro, M. J. Beceiro-Gonzalez, E. Muniategui-Lorenzo, S. Prada-Rodriguez, D. Univ A Coruna Dept Analyt Chem E-15071 La Coruna Spain

A method using dual process columns of Matrix Solid Phase Dispersion (MSPD) and Solid Phase Extraction (SPE) has been developed for extracting and cleaning-up of nine triazine herbicides (ametryn, atrazine, cyanazine, prometryn, propazine, simazine, simetryn, terbuthylazine and terbutryn) in seaweed samples. Under optimized conditions, samples were blended with 2 g of octasilyl-derivatized silica (C-8) and transferred into an SPE cartridge containing ENVI (TM)-Carb II/PSA (0.5/0.5 g) as a clean up co-sorbent Then the dispersed sample was washed with 10 mL of n-hexane and triazines were eluted with 20 mL ethyl acetate and 5 mL acetonitrile. Finally the extract was concentrated to dryness, re-constituted with 1 mL methanol:water (1:1) and injected into the HPLC-DAD system. The linearity of the calibration curves was excellent in matrix matched standards, and yielded the coefficients of determination >= 0.995 for all the target analytes. The recoveries ranged from 75% to 100% with relative standard deviations lower than 7%. The achieved LOQs (< 10 mu g kg(-1)) for all triazines under study permits to ensure proper determination at the maximum allowed residue levels set in the European Union Legislation. Samples of three seaweeds were subjected to the procedure proving the suitability of MSPD method for the analysis of triazines in different seaweeds samples. (C) 2014 Elsevier B.V. All rights reserved.

关键词： Triazine herbicides Seaweeds Matrix Solid Phase Dispersion Solid Phase Extraction High Performance Liquid Chromatography diode array detection

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Validated stability-indicating HPLC-DAD method for determination of the phosphodiesterase (PDE-4) inhibitor roflumilast

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Bulletin of Faculty of Pharmacy, Cairo University 2014年第1期52卷 79-89页

作者： Tarek S. Belal Hytham M. Ahmed Mohamed S. Mahrous Hoda G. Daabees Mostafa M. Baker Pharmaceutical Analytical Chemistry Department Faculty of Pharmacy University of Alexandria Elmessalah 21521 Alexandria Egypt Pharmaceutical Analysis Department Faculty of Pharmacy Damanhour University Damanhour Egypt Pharmaceutical Chemistry Department Faculty of Pharmacy University of Alexandria Elmessalah 21521 Alexandria Egypt Pharmaceutical Chemistry Department Faculty of Pharmacy Damanhour University Damanhour Egypt Methodology Department Pharco Pharmaceuticals Company Alexandria Egypt

A comprehensive stability indicating HPLC with diode array detection method was developed for determination of the recently approved phosphodiesterase type 4 (PDE-4) inhibitor roflumilast (RFL). Effective chromatographic separation was achieved using Durashell C18 column (4.6 × 250 mm, 5 μm particle size) with isocratic elution of the mobile phase composed of 0.0065 M ammonium acetate pH 6.3, methanol and acetonitrile in the ratio of 30:35:35 (by volume). The mobile phase was pumped at a flow rate of 1.3 mL/min, and quantification of RFL was based on measuring its peak areas at 251 nm. RFL eluted at retention time 6.2 min. Analytical performance of the proposed HPLC procedure was thoroughly validated with respect to system suitability, linearity, range, precision, accuracy, specificity, robustness, detection and quantification limits. The linearity range was 2.5–200 μg/mL with correlation coefficient >0.9998. The drug was subjected to stress conditions of neutral, acidic and alkaline hydrolysis, oxidation, photolysis and thermal degradation. The proposed method proved to be stability-indicating by resolution of the drug from its forced degradation products. Moreover, specificity of the method was verified by resolution of drug from more than 20 pharmaceutical compounds of various medicinal categories. The validated HPLC method was successfully applied to the analysis of the cited drug in its tablet dosage form. The proposed method made use of DAD as a tool for peak identity and purity confirmation.

关键词： HPLC diode array detection Roflumilast Stability-indicating assay Forced degradation

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Development of a Rapid LC-DAD/FLD Method for the Simultaneous Determination of Auxins and Abscisic Acid in Plant Extracts

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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2013年第46期61卷 10940-10947页

作者： Bosco, Renato Caser, Matteo Vanara, Francesca Scariot, Valentina Univ Torino Dept Agr Forest & Food Sci I-10095 Grugliasco To Italy

Plant hormones play a crucial role in controlling plant growth and development. These groups of naturally occurring substances trigger physiological processes at very low concentrations, which mandate sensitive techniques for their quantitation. This paper describes a method to quantify endogenous (+/-)-2-cis-4-trans-abscisic acid, indole-3-acetic acid, indole-3-propionic acid, and indole-3-butyric acid. The method combines high-performance liquid chromatography (HPLC) with diode array and fluorescence detection in a single run. Hybrid tea rose 'Monferrato' matrices (leaves, petals, roots, seeds, androecium, gynoecium, and pollen) were used as references. Rose samples were separated and suspended in extracting methanol, after which (+/-)-2-cis-4-trans-abscisic acid and auxins were extracted by solvent extraction. Sample solutions were added first to cation solid phase extraction (SPE) cartridges and the eluates to anion SPE cartridges. The acidic hormones were bound to the last column and eluted with 5% phosphoric acid in methanol. Experimental results showed that this approach can be successfully applied to real samples and that sample preparation and total time for routine analysis can be greatly reduced.

关键词： abscisic acid auxins indole-3-acetic acid indole-3-butyric acid indole-3-propionic acid HPLC fluorescence detection diode array detection SPE Rosa

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Validated Stability-Indicating HPLC-DAD Determination of the Antihypertensive Binary Mixture of Carvedilol and Hydrochlorothiazide in Tablet Dosage Forms

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CHROMATOGRAPHIA 2013年第23-24期76卷 1707-1720页

作者： Belal, Tarek S. Shaalan, Rasha A. El Yazbi, Fawzy A. Elonsy, Sohila M. Univ Alexandria Dept Pharmaceut Analyt Chem Fac Pharm Alexandria 21521 Egypt Damanhour Univ Dept Pharmaceut Analyt Chem Fac Pharm Damanhour Egypt

A simple and selective HPLC with diode array detection stability-indicating method was developed for the simultaneous determination of the antihypertensive drugs carvedilol (CRV) and hydrochlorothiazide (HCT) in their combined formulations. Effective chromatographic separation was achieved using Zorbax SB-C8 column (4.6 x 250 mm, 5 mu m) with gradient elution of the mobile phase composed of 0.025 M phosphoric acid and acetonitrile at a flow rate of 1 mL min(-1). The multiple wavelength detector was set at 242 nm for measurement of CRV and 271 nm for HCT. Quantification was based on measuring the peak areas. The cited drugs were resolved with retention times 4.9 and 6.7 min for HCT and CRV, respectively. Analytical performance of the proposed HPLC procedure was thoroughly validated with respect to system suitability, linearity, ranges, precision, accuracy, specificity, robustness, detection and quantification limits. The linearity ranges were 5-300 and 5-200 mu g mL(-1) for CRV and HCT, respectively, with correlation coefficients > 0.9996. Both drugs were subjected to stress conditions of acidic and alkaline hydrolysis, oxidation, photolysis and thermal degradation. The proposed method proved to be stability-indicating by resolution of the drugs from their forced degradation products. Moreover, specificity of the method was verified by resolution of both drugs from more than 20 pharmaceutical compounds of various medicinal categories. The validated HPLC method was applied to the analysis of the cited antihypertensive drugs in their combined tablet dosage forms. The proposed method made use of DAD as a tool for peak identity and purity confirmation.

关键词： Column liquid chromatography diode array detection Carvedilol Hydrochlorothiazide Stability-indicating assay Forced degradation Tablets dosage form

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Direct quantitative determination of amlodipine enantiomers in urine samples for pharmacokinetic study using on-line coupled isotachophoresis-capillary zone electrophoresis separation method with diode array detection

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JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES 2008年第1期875卷 266-272页

作者： Mikus, Peter Marakova, Katarina Marak, Jozef Nemec, Igor Valaskova, Iva Havranek, Emil Comenius Univ Fac Pharm Dept Pharmaceut Anal & Nucl Pharm SK-83232 Bratislava Slovakia Comenius Univ Fac Nat Sci Dept Analyt Chem SK-84215 Bratislava Slovakia

The present work illustrates possibilities of column-coupling capillary electrophoresis (CE-CE) combined with chiral selector (2-hydroxypropyl-beta-cyclodextrin. HP-beta-CD) and fiber-based diode array detection (DAD) for the direct quantitative enantioselective determination of trace drug (amlodipine, AML) in biological multicomponent ionic matrices (human urine). Capillary isotachophoresis (ITP) served as an ideal injection technique in CE-CE. Moreover. the ITP provided an effective on-line sample pretreatment prior to the capillary zone electrophoresis (CZE) separation. Enhanced separation selectivity due to the combination of different separation mechanisms (ITP vs. CZE-HP-beta-CD) enabled to obtain pure zones of the analytes, suitable for their detection and quantitation. The DAD, unlike single wavelength UV detection enabled to characterize the purity (i.e. spectral homogeneity) of the analytes zones. A processing of the raw DAD spectra (the background correction and smoothing procedure) was essential when a trace analyte signal was evaluated. Obtained results indicated pure (i.e. spectrally homogeneous) zones of interest confirming effective ITP-CZE separation process. The proposed ITP-CZE-DAD method was characterized by favorable performance parameters (sensitivity, linearity, precision, recovery, accuracy, robustness, selectivity) and successfully applied to an enantioselective pharmacokinetic study of AML. (c) 2008 Elsevier B.V. All rights reserved.

关键词： Isotachophoresis Capillary zone electrophoresis Column-coupling electrophoresis diode array detection Chiral drug Amlodipine enantiomers Cyclodextrin Human urine

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Possibilities of column coupling electrophoresis provided with a fiber-based diode array detection in enantio selective analysis of drugs in pharmaceutical and clinical samples

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JOURNAL OF CHROMATOGRAPHY A 2008年第1期1179卷 9-16页

作者： Mikus, Peter Marakova, Katarina Marak, Jozef Kaniansky, Dusan Valagkova, Iva Havranek, Emil Comenius Univ Fac Pharm Dept Pharmaceut Anal & Nucl Pharm SK-83232 Bratislava Slovakia Comenius Univ Fac Nat Sci Dept Analyt Chem SK-84215 Bratislava Slovakia

The present work illustrated possibilities of column coupling electrophoresis combined with ionizable chiral selector and diode array detection (DAD) for the enantioselective analysis of trace drugs (pheniramine and its analogs) in pharmaceutical and clinical samples. lsotachophoresis (ITP), on-line coupled with capillary zone electrophoresis (CZE), served as an ideal injection technique (high sample load capacity, narrow and sharp drugs zones) of on-line pretreated samples (preseparation, purification and preconcentration of drugs) for the CZE stage. Enhanced (enantio)separation selectivity of CZE with ionizable chiral selector (carboxyethyl-beta-cyclodextrin recognized between drugs enantiomers on one hand as well as between drugs and sample matrix constituents on the other hand) enabled to obtain pure zones of the drugs enantiomers, suitable for their detection and quantitation. DAD in comparison with single wavelength UV detection enhanced value of analytical information verifying purity of drugs enantiomers zones (indicating interferents with different spectra to those of drugs). Obtained results indicated pure zones of interest confirming effective ITP-CZE (enantio)separation process. Distinguishing the trace analytes signals superposed on the baseline noise was provided with sufficient reliability (for this purpose the background correction and smoothing procedure had to be applied to the raw DAD spectra). The proposed ITP-CZE-DAD methods were characterized by favorable performance parameters (sensitivity, linearity, precision, recovery, accuracy, robustness, selectivity) and successfully applied for (i) enantiomeric purity testing of dexbrompheniramine in commercial pharmaceutical tablets and (ii) enantioselective metabolic study of pheniramine in human urine. (c) 2007 Elsevier B.V. All rights reserved.

关键词： isotachophoresis capillary zone electrophoresis column-coupling diode array detection drug charged cyclodextrin enantiomer purity pharmaceuticals clinical analysis multicomponent mixture

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Determination of nine active components in Radix Hedysari and Radix Astragali using capillary HPLC with diode array detection and MS detection

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JOURNAL OF SEPARATION SCIENCE 2008年第2期31卷 255-261页

作者： Zhao, Jing Yu, Qing-Tao Li, Ping Zhou, Peng Zhang, Yuan-Jie Wang, Wei China Pharmaceut Univ Key Lab Modern Chinese Med Minist Educ Nanjing 210009 Peoples R China

A capillary HPLC (cHPLC) coupled with diode array detection (DAD) and MS method was developed for the simultaneously qualitative and quantitative determination of nine components, namely vanillic acid, calycosin-7-O-beta-D-glucoside, (6 alpha R,11 alpha R)-9,10-dimethoxypterocarpan-3-O-beta-D-glucoside, ononin, calycosin, (3R)-2'-hydroxy-3',4'-dimethoxyisoflavan-7-O-beta-D-glucoside, isoliquiritigenin, formononetin, (3R)-8,2'-dihydroxy-7,4'-dimethoxyisoflavan, in Radix Hedysari (Hongqi) and Radix Astragali (Huangqi). Simultaneous separation of these nine compounds was achieved on a Zorbax C18 microcolumn (5 mu m, 150 x 0.3 mm). The mobile phase consisted of (A) 0.3% aqueous formic acid and (B) ACN with a gradient elution. The identification of nine compounds in both Hongqi and Huangqi was confirmed by TOF-MS. All calibration curves showed good linearity (R-2 >0.998) within test ranges. This method showed good repeatability for the quantification of these nine components in Hongqi and Huangqi with intra- and inter-day variations of less than 1.89 and 3.13%, respectively. The validated method was successfully applied to quantify nine investigated components in eighteen samples of Hongqi and Huangqi. Hierarchical cluster analysis of 18 samples was performed using the peak area of nine analytes on cHPLC chromatograms. The result showed that Hongqi and Huangqi are significantly different, though the two species of Astragalus are very similar.

关键词： capillary HPLC diode array detection MS Radix Astragali Radix Hedysari

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Potentialities of ITP-CZIE method with diode array detection for enantiomeric purity control of dexbrompheniramine in pharmaceuticals

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JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS 2008年第5期46卷 870-876页

作者： Marak, Jozef Mikus, Peter Marakova, Katarina Kanianskya, Dusan Valaskova, Iva Havranek, Emil Comenius Univ Fac Nat Sci Dept Analyt Chem SK-84215 Bratislava Slovakia Comenius Univ Fac Pharm Dept Pharmaceut Anal & Nucl Pharm SK-83232 Bratislava Slovakia

The present work illustrates potentialities of on-line combined isotachophoresis-capillary zone electrophoresis (ITP-CZE) separation techniques coupled with on-capillary diode array detector (DAD) for enantiomeric purity testing of drugs in pharmaceuticals. The general advantages of the proposed method are its (i) high selectivity, (ii) low concentration limit of detection (LOD) obtainable, (iii) enhanced sample loadability, and (iv) enhanced reliability. For separation of brompheniramine (BP) enantiomers, serving as model analytes, carboxyethyl-beta-cyclodextrin (CE-beta-CD) was appropriate chiral selector providing complete enantioresolution. Given by a high sample load capacity (30 mu l sample injection volume) and preconcentration of the analytes in ITP stage, concentration LOD of levobrompheniramine (LBP), serving as model impurity, was 2.5 ng/ml (8 x 10(-9) mol/l). Such separation and detection conditions enabled to easily determine LBP in samples containing a 103 excess of dexbrompheniramine (DBP). DAD detection in comparison with single wavelength detection can enhance value of analytical information when analytes and interferents have different spectra (distinguishing impurities in analyte zone, confirmation of migration positions of migrants). In this context purity of BP zones was confirmed with higher reliability in pharmaceutical sample. Moreover, distinguishing the trace analyte signal superposed on the baseline noise was provided with sufficient reliability (for this purpose the background correction and smoothing procedure had to be applied to the raw DAD spectra). Successful validation and application of the proposed ITP-CZE-DAD method suggest its routine use for the enantiomeric purity testing of pharmaceuticals. (C) 2007 Elsevier B.V. All rights reserved.

关键词： column-coupling electrophoresis diode array detection dexbrompheniramine enantiomeric purity cyclodextrin

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Determination of some carbamate pesticides in watermelon and tomato samples by dispersive liquid-liquid microextraction combined with high performance liquid chromatography

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INTERNATIONAL JOURNAL OF ENVIRONMENTAL ANALYTICAL CHEMISTRY 2012年第5期92卷 571-581页

作者： Liu, Zhimei Liu, Weihua Rao, Huan Feng, Tao Li, Chao Wang, Chun Wang, Zhi Agr Univ Hebei Coll Sci Key Lab Bioinorgan Chem Baoding 071001 Peoples R China Agr Univ Hebei Coll Food Sci & Technol Baoding 071001 Peoples R China

A novel method for the determination of five carbamate pesticides (metolcarb, carbofuran, carbaryl, isoprocard and diethofencard) in watermelon and tomato samples was developed by dispersive liquid-liquid microextraction (DLLME) coupled with high performance liquid chromatography-diode array detection (HPLC-DAD). Some experimental parameters that influence the extraction efficiency were studied and optimised to obtain the best extraction results. Under the optimum conditions for the method, the calibration curve was linear in the concentration range from 10 to 1000 ng g(-1) for all the five carbamate pesticides, with the correlation coefficients (r) varying from 0.9982 to 0.9992. Good enrichment factors were achieved ranging between 80 and 177, depending on the compound. The limits of detection (LODs) (S/N = 3) were ranged from 0.5 to 1.5 ng g(-1). The method has been successfully applied to the analysis of the pesticide residues in watermelon and tomato samples. The recoveries of the method fell in the range between 76.2% to 94.5% with RSDs less than 9.6%, indicating the feasibility of the DLLME method for the determination of the five carbamate pesticides in watermelon and tomato samples.

关键词： carbamate pesticides high performance liquid chromatography diode array detection dispersive liquid-liquid microextraction watermelon tomato

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