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Analysis of methylglyoxal in water and biological matrices by capillary zone electrophoresis with diode array detection

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ELECTROPHORESIS 2005年第9期26卷 1760-1767页

作者： do Rosário, PMA Cordeiro, CAA Freire, AP Nogueira, JMF Univ Lisbon Dept Chem & Biochem P-1699 Lisbon Portugal Univ Lisbon Ctr Chem & Biochem P-1699 Lisbon Portugal Univ Lisbon Ctr Mol Sci & Mat P-1699 Lisbon Portugal

We describe a new method for the determination of methylglyoxal in water and biological matrices, using o-phenylenediamine as derivatizing agent and solid-phase extraction followed by capillary zone electrophoresis with diode array detection. 25 mm sodium phosphate running buffers at pH 2.2, 30 kV, and 25degrees C allowed the best instrumental conditions for the optimum separation of methylglyoxal in a suitable analytical time (<10 min), using an uncoated fused-silica capillary of 75 mum inner diameter and an effective length of 45.1 cm with an extended light path and the wavelength set to 200 nm. Under optimized instrumental conditions, good reproducibility of the migration time (<1.1%), precision (<5%), an excellent linear dynamic range from 0.1 to 3.6 mg/L (r(2) = 0.9997), and low limits of detection (7.2 mu g/L) were obtained for methylglyoxal measurements, using the internal standard methodology. Assays on laboratory-spiked tap and ground water samples allowed a remarkable accuracy, presenting yields of 95.0 +/- 4.3 and 94.0 +/- 1.1%, respectively, and good performance to determine methylglyoxal in beer and yeast cells suspensions matrices was also obtained at trace level. The present methodology is a cost-effective alternative for routine quality control analysis, showing to be reliable, sensitive, and with a low sample volume requirement to monitor methylglyoxal in water and biological matrices.

关键词： beer capillary zone electrophoresis diode array detection methylglyoxal Saccharomyces cerevisiae water analysis

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Simultaneous Determination of Antibiotics in Anti-Acne Cosmetics by Rapid LC with DAD

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CHROMATOGRAPHIA 2009年第11-12期69卷 1221-1226页

作者： Jin, Wei Yang, Yong-Jian Wang, Wei-Yu Ye, Jian-Nong E China Normal Univ Dept Chem Shanghai 200062 Peoples R China Shanghai Inst Food & Drug Control Shanghai 201203 Peoples R China

A suitable method that allows, for the first time, the simultaneous determination of nine antibiotics which may help the therapy of acne vulgaris by rapid liquid chromatography with diode array detection in 7 min is presented in this work. An SB RP18 (50 x 4.6 mm;1.8 mu m particle size) column was used with the mobile phase consisting of a mixture of 0.1 mol L-1 potassium clihydrogen phosphate (pH 2.5) and acetonitrile at the gradient elution program. The correlation coefficients were all above 0.9999 in the linear range between 4-100 mu g mL(-1), the average spiked recoveries (n = 6) were 92.2-103.2% with RSD ranging from 0.04 to 4.5% depending on the target analytes. The method detection limits were in the range of 0.02-0.2 mu g mL(-1) in anti-acne cosmetics. The analysis of real cosmetic preparations demonstrated the fitness for the whole analytical procedure. The proposed method appeared therefore as a sound alternative for official testing method, which could overcome the general problems of time consuming, lack of the specificity and precision difficulty.

关键词： Column liquid chromatography diode array detection Anti-acne cosmetics Antibiotics

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Automatic in-tube SPME and fast liquid chromatography:: A cost-effective method for the estimation of dibuthyl and di-2-ethylhexyl phthalates in environmental water samples

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ANALYTICA CHIMICA ACTA 2008年第2期610卷 268-273页

作者： Chafer-Pericas, C. Campins-Falco, P. Prieto-Blanco, M. C. Univ Valencia Fac Quim Dept Quim Analit E-46100 Valencia Spain Univ A Coruna Dept Analyt Chem E-15071 La Coruna Spain

A 80-cm length commercially available capillary coated with 95% polydimethylsiloxane and 5% polydiphenylsiloxane (TBR-5) was employed to carry out on-line extraction and preconcentration of dibuthyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP) in the chromatographic system. The coated capillary was placed between the sample injection loop and the injection needle of an autosampler. Variables affecting the automatic in-tube solid-phase microextraction (SPME) were optimized. A Genesis C-18 (5 cm x 4.6 min i.d., 4 mu m particle size) was employed as analytical column. The achieved limits of detection by use of diode array detection were I and 2.S mu g L-1, respectively. The proposed conditions have been applied to determine those compounds at low ppb levels (<= 250 mu g L-1) in aqueous samples. No matrix effect was found, and recoveries between 85 and 115% were obtained. The precision of the method was good, and the achieved intra- and inter-day variation coefficients were between 5 and 20%. The analysis time per sample was 20 min and any off-line pretreatment of the samples was needed. The taken sample volume was 100 mu L. Data on the application of the described method to the analysis of different water samples are presented. (c) 2008 Elsevier B.V. All rights reserved.

关键词： in-tube solid-phase microextraction dibuthyl phthalate di-2-ethylhexyl phthalate liquid chromatography diode array detection automatic method

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Simultaneous determination of water- and fat-soluble vitamins in pharmaceutical preparations by high-performance liquid chromatography coupled with diode array detection

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ANALYTICA CHIMICA ACTA 2004年第1-2期520卷 57-67页

作者： Klejdus, B Petrlová, J Potesil, D Adam, V Mikelová, R Vacek, J Kizek, R Kubán, V Mendel Univ Brno Dept Chem & Biochem CZ-61300 Brno Czech Republic

Water- and fat-soluble vitamins were separated on a MetaChem Polaris C18-A (150 mm x 4.6 mm, 3 mum particle size) in a single run using combined isocratic and linear gradient elution with a mobile phase consisting of 0.010% trifluoroacetic acid of pH 3.9 (solvent A) and methanol (solvent B) at the flow rate 0.7 ml min(-1). A linear gradient profile (A:B) started at 95:5 and was constant in the first 4 min, then linearly decreased up to 2:98 during the next 6 min, then it was constant in the next 20 min and finally linearly increased up to 95:5 ratio of water phase in the last 5 min of the separation. The most suitable detection wavelength for simultaneous vitamin determination was 280 nm. The method was applied for the solid sample of pharmaceutical preparation (B-Komplex), fortified powdered drinks (multi-vitamin) and food samples. The results were in good agreement with the declared values. (C) 2004 Elsevier B.V. All rights reserved.

关键词： simultaneous determination vitamins water and fat-soluble vitamins high-performance liquid chromatography pharmaceutical preparations drugs diode array detection mass spectrometry

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Determination of dissociation constants of pharmacologically active xanthones by capillary zone electrophoresis with diode array detection

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JOURNAL OF CHROMATOGRAPHY A 2004年第2期1061卷 217-223页

作者： Wu, XM Gong, SX Bo, T Liao, YP Liu, HW Peking Univ Inst Analyt Chem Coll Chem & Mol Engn Key Lab Bioorgan Chem & Mol EngnMinist Educ Beijing 100871 Peoples R China

In this article, the dissociation constants (pK(a)) of 10 pharmacologically active xanthones isolated from herbal medicine Securidaca inappendiculata were determined by capillary zone electrophoresis with diode array detection. The pK(a) values determined by the method based on the electrophoretic mobilities (calculated from migration times) have been proved by the method based on UV absorbance calculated from the online spectra corresponding peaks. No conspicuous difference was observed between the two methods with acceptable reproducibility. Two pK(a) values (pK(a1) and pK(a2)) were found for four xanthones while generally the 10 compounds possess the pK(a) values ranging from 6.4 to 9.2. (C) 2004 Elsevier B.V. All rights reserved.

关键词： dissociation constant xanthone capillary zone electrophoresis diode array detection herbal medicine

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Simultaneous determination of five phenolic compounds in dried flowers by LC using DAD combined electrochemical detection

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CHROMATOGRAPHIA 2007年第11-12期65卷 707-712页

作者： Zheng, Jian-bin Liu, Xiao-xing Zhou, Yuan-zhen Suo, Zhi-rong NW Univ Xian Inst Analyt Sci Shaanxi Prov Key Lab Electroanalyt Chem Xian 710069 Peoples R China

A simple, sensitive and accurate method for the simultaneous separation and determination of apigenin and four phenolic acids including chlorogenic acid, caffeic acid, p-coumaric acid and ferulic acid in four dried flowers by high performance liquid chromatography with electrochemical detection (ECD) and diode array detection (DAD) has been established. The detection limits of caffeic acid, p-coumaric acid and ferulic acid obtained with ECD were 3, 1 and 4 ng mL(-1), and LOD of apigenin and chlorogenic acid obtained with DAD were 1 X 10(-2) and 6 x 10(-2) mu g mL(-1). The detection and quantification limits of three phenolic compounds obtained with ECD were two to ninefold greater than those obtained with DAD. As electrochemically inactive compounds, apigenin and chlorogenic acid were detected by DAD. All calibration curves showed good linearity (r >= 0.9992) within the test ranges. The recoveries ranged from 95.3 to 101.4% (RSD <= 2.9%). This approach could provide scientific evidence for comprehensive evaluation about the effect of the medicine and ensure nutrient status of dried flowers.

关键词： column liquid chromatography electrochemical detection diode array detection flavonoid phenolic acid dried flowers

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Analysis of terbumeton and its major metabolites by SPE and DAD-HPLC in soil bulk water

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CHROMATOGRAPHIA 2007年第3-4期65卷 155-161页

作者： Conrad, A. Couderchet, M. Biagianti-Risbourg, S. Univ Reims Lab Ecotoxicol Unite Rech Vignes & Vins Champagne F-51687 Reims 02 France Univ Reims Lab Plantes Pesticides & Dev Durable Unite Rech Vignes & Vins Champagne F-51687 Reims France

A rapid and inexpensive method for simultaneous quantification of terbumeton (TER), and its major potential metabolites (TED;terbumeton-desethyl, TOH;terbumeton-2-hydroxy and TID;terbumeton-deisopropyl) in soil bulk water (SBW) samples is proposed. The analytical method involves extraction-concentration from SBW samples using a graphitized carbon black (GCB) cartridge followed by their separation-detection by reversed-phase high-performance liquid chromatography analysis using a C-18 column and a diode array detector. A mobile phase of acetonitrile-0.005 mol L-1 phosphate buffer (pH 7.0) (35:65, v/v) at a flow rate of 0.8 mL min(-1) in isocratic elution mode has been used. After optimization of the extraction and separation conditions, this method can be used for the simultaneous determination of investigated compounds in the range of the international limits of 0.1 mu g L-1. For TER the detection limit was 0.009 mu g L-1 and it was 0.100, 0.550, and 0.480 mu g L-1 for TED, TOH, and TID, respectively. The recoveries of TER, TED, TOH, and TID from SBW samples, measured at three levels of concentration range, were found to be between 48.0 and 102.0%. The intra-day precision measured by relative standard deviation (RSD) was always lower than 9.0%.

关键词： column liquid chromatography solid-phase extraction diode array detection soil bulk water s-triazine herbicides

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Quality evaluation of Radix Stemonae through simultaneous quantification of bioactive alkaloids by high-performance liquid chromatography coupled with diode array and evaporative light scattering detectors

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BIOMEDICAL CHROMATOGRAPHY 2007年第10期21卷 1088-1094页

作者： Li, Song-Lin Jiang, Ren-Wang Hon, Po-Ming Cheng, Ling Xu, Hong-Xi Greger, Harald But, Paul Pui-Hay Shaw, Pang-Chui Chinese Univ Hong Kong Inst Chinese Med Dept Biochem Hong Kong Peoples R China Hong Kong Jockey Club Inst Chinese Med Hong Kong Peoples R China Univ Vienna Inst Bot Comparative & Ecolog Phytochem Sect A-1010 Vienna Austria

A high-performance liquid chromatography coupled with diode array detection and evaporative light scattering detection (HPLC-DAD-ELSD) method was developed to simultaneously quantify six major bioactive alkaloids belonging to different structure types in Radix Stemonae, Bai-Bu in Chinese, a traditionally used antitussive and insecticidal medicinal material in China and other countries of Southeast Asia. diode array detector (DAD) with the wavelengths at 307 and 260 nm was used to monitor the conjugated system of protostemonine (2) and maistemonine (4), respectively, whereas evaporative light scattering detector (ELSD) was employed to detect croomine (1), stemoninine (3), neotuberostemonine (5) and tuberostemonine (6), the other four analytes with no or poor chromophores. The assay was validated to be sensitive, precise and accurate, with a detection limit of 3.64-0.04 mu g/mL depending on the individual analytes. The overall intra- and inter-day variations were less than 9.3%, and the overall recoveries higher than 91.2%, respectively. The correlation coefficients of the calibration curves were better than 0.996 for all analytes. The newly established method was successfully utilized to determine six major components in the genuine sources of Radix Stemonae: Stemona japonica, S. sessilifolia and S. tuberosa. Significant variations of contents of these components were demonstrated in samples of these three species. This simple, rapid, low-cost and reliable method is suitable for the routine quality control of herbal medicines containing bioactive components with different structure types such as Radix Stemonae. Copyright (c) 2007 John Wiley & Sons, Ltd.

关键词： high-performance liquid chromatography diode array detection evaporative light scattering detection Stemona alkaloids S. tuberosa S. japonica S. sessilifolia

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Development and validation of an RP-HPLC method for determination of valganciclovir in human serum and tablets

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CHROMATOGRAPHIA 2007年第1-sup期66卷 S97-S101页

作者： Dogan-Topal, B. Uslu, B. Ozkan, S. A. Ankara Univ Fac Pharm Dept Analyt Chem TR-06100 Ankara Turkey

This paper describes the validation of an isocratic high-performance liquid chromatographic method for the assay of valganciclovir in raw materials, tablets and human serum samples. Valganciclovir and fluvastatin (internal standard) were well separated using a reversed phase column and a mobile phase consisting of a mixture of acetonitrile:metkanol:KH2PO4 (0.02 M) (40:20:40;v/v/v) (at pH 5.0). The mobile phase was pumped at 1.0 mL min(-1) flow rate and valganciclovir was detected by diode-array detection at 255 nm. The retention times for valganciclovir and fluvastatin were 3.41 and 5.60 min, respectively. A linear response (r > 0.999) was observed in the range of 10-30,000 ng mL(-1) in mobile phase and serum. The limit of detection and limit of quantification were found as 2.95 and 9.82 ng mL(-1) in mobile phase and 1.73 and 5.77 ng mL(-1) in human serum samples, respectively. Validation parameters as precision, accuracy, selectivity, reproducibility and system suitability tests were also determined. The method can be used for valganciclovir assay of tablets and human serum samples as the method separates valganciclovir from tablet excipients and endogenous substances.

关键词： column liquid chromatography reversed phase diode array detection valganciclovir in human serum and tablets

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Evaluation of the multivariate selectivity of multi-way liquid chromatography methods

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JOURNAL OF CHEMOMETRICS 2007年第7-9期21卷 335-345页

作者： Cantwell, Marc T. Porter, Sarah E. G. Rutan, Sarah Ca Virginia Commonwealth Univ Dept Chem Richmond VA 23284 USA

Multivariate figures of merit are used to characterize the sensitivity, selectivity, and precision of multi-dimensional liquid chromatography (LC) methods. Specifically in this work, we used a multivariate selectivity parameter to characterize the performance of orthogonal LC and two-dimensional liquid chromatography (2D-LC) methods with and without diode array detection (DAD), and to aid in the optimization of these new separation approaches. We found that the average selectivity of 47 drug compounds was increased by as much as 58% upon the addition of a second, orthogonal separation. We also found that the selectivity for some individual drug compounds improved by more than a factor of two when DAD detection was used compared to single wavelength detection. In the comprehensive 2D-LC simulations, using a multi-channel detector increased the average selectivity of 500 components by 7.3% for a 21 s cycle time. The multivariate selectivity parameter was shown to be useful for determining the information gained when additional dimensions of data are collected on multi-dimensional instrumentation. Copyright (c) 2007 John Wiley & Sons, Ltd.

关键词： two-dimensional liquid chromatography diode array detection orthogonal liquid chromatography PARAFAC

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