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Development of a Matrix Solid Phase Dispersion methodology for the determination of triazine herbicides in mussels

FOOD CHEMISTRY 2015年 173卷 391-396页

作者： Rodriguez-Gonzalez, N. Gonzalez-Castro, M. J. Beceiro-Gonzalez, E. Muniategui-Lorenzo, S. Univ A Coruna Fac Ciencias Grupo Quim Analit Aplicada Inst Univ Medio AmbienteDept Quim Analit La Coruna 15071 Spain

A method based on Matrix Solid Phase Dispersion (MSPD) for determination of nine triazines in mussels has been optimised in terms of the sorbents used for extracting and cleaning-up. Two dispersing agents: C-18 and florisil, and eight cleanup co-sorbents: florisil, silica, silica/alumina, Envi (TM) Carb, Envi-Carb-II/PSA, SAX/PSA, Envi-Carb-II /SAX/PSA and C-18 were assayed. Analytes were eluted using 20 mL of ethyl acetate and 5 mL of acetonitrile and finally the extract was concentrated to dryness, re-constituted with 1 mL methanol and determined by HPLC-DAD. The best results were obtained with C-18 as dispersing agent and Envi-Carb-II/SAX/PSA as clean-up co-column. Recoveries ranged between 79% and 99% and repeatability and reproducibility were below than 16% for all compounds. The linearity of the calibration curves yielded the R-2 >= 0.9993. The LOQ values ranged from 0.10 to 0.18 mg kg(-1) dried sample. Finally the method was applied to the analysis of mussel samples from Galicia (NW Spain). (C) 2014 Elsevier Ltd. All rights reserved.

关键词： Triazines Mussel Matrix Solid Phase Dispersion High performance liquid chromatography diode array detection

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Simple UHPLC-DAD Method for the Direct Determination of Donepezil in Cerebrospinal Fluid

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JOURNAL OF LIQUID CHROMATOGRAPHY & RELATED TECHNOLOGIES 2015年第10期38卷 1068-1072页

作者： Kovatsi, Leda Tsolaki, Magda Gkatzima, Olymbia Petrocheilou, Maria Samanidou, Victoria Aristotle Univ Thessaloniki Sch Med Lab Forens Med & Toxicol Thessaloniki Greece Aristotle Univ Thessaloniki GH G Papanicolaou Dept Neurol 3 Thessaloniki Greece Aristotle Univ Thessaloniki Dept Chem Analyt Chem Lab Thessaloniki Greece

Donepezil is an acetylcholinesterase inhibitor administered to patients who suffer from Alzheimer's Disease (AD). We have currently developed and validated a UHPLC-DAD method for the determination of donepezil in cerebrospinal fluid. The retention time of the drug was 2.4min and the total time of analysis was 6min. Validation was performed in terms of linearity, selectivity, accuracy, precision, and stability. Following validation, the method was applied to clinical cerebrospinal fluid samples. The currently developed method is a reliable tool for monitoring CSF donepezil levels in patients under treatment with this drug.

关键词： diode array detection Cerebrospinal fluid UHPLC donepezil

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Dynamics of abscisic acid and indole-3-acetic acid during the early-middle stage of seed development in Rosa hybrida

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PLANT GROWTH REGULATION 2015年第1期75卷 265-270页

作者： Bosco, Renato Caser, Matteo Ghione, Gian Guido Mansuino, Andrea Giovannini, Annalisa Scariot, Valentina Univ Torino Dept Agr Forest & Food Sci I-10095 Grugliasco TO Italy NIRP Int Az Agr Ghione L & Figli I-18039 Ventimiglia IM Italy Consiglio Ric & Sperimentaz Agr Unita Ric Floricoltura & Specie Ornamentali I-18038 San Remo IM Italy

Concentrations of endogenous abscisic acid (ABA) and indole-3-acetic acid (IAA) in Rosa hybrida seed coat and embryos were determined at 28, 35, 42, and 49 days after pollination (DAP), a period encompassing the early-middle stages of seed development. No studies on rose have ever documented simultaneous change in ABA and IAA during these developmental phases in both seed coat and embryo. Plant growth regulators were extracted and then quantified by using high performance liquid chromatography based on solid phase extraction purification. In both the seed coat and embryo, ABA content decreased from 28 DAP (4.39 and 1.36 pmol mg(-1), respectively) and onward. Endogenous IAA in seed coat followed the same trend. In contrast, IAA in embryo began to increase at 28 DAP (2.06 pmol mg(-1)), peaked at 42 DAP (5.06 pmol mg(-1)), and then declined dramatically at 49 DAP (1.17 pmol mg(-1)). In embryo, the IAA/ABA ratio was always[1.0 and showed a tendency to increase from 28 DAP to the maximum significant rate at 42 DAP (9.20). The ABA decrease associated with increased IAA levels in embryo could be a result of crosstalk between these two phytohormones. Such a change in the IAA/ABA ratio may signal the end of endodormancy caused by ABA at the pre-cotyledonary stage and the start of increased embryo cell division during the cotyledonary stage, which also results in increased hip weight.

关键词： diode array detection Fluorescence detection High-performance liquid chromatography Hybrid tea rose Plant growth regulators Seed dormancy Seed germination

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Analysis of Non-Aromatic Organic Acids in Beer by CE and Direct detection Mode with diode array detection

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CHROMATOGRAPHIA 2009年第11-12期70卷 1737-1742页

作者： Erny, Guillaume L. Rodrigues, Joao E. A. Gil, Ana M. Barros, Antonio S. Esteves, Valdemar I. Univ Aveiro Dept Chem CESAM P-3810193 Aveiro Portugal Univ Aveiro Dept Chem CICECO P-3810193 Aveiro Portugal Univ Aveiro Dept Chem QOPNAA P-3810193 Aveiro Portugal

A method for the analysis of the main non-aromatic organic acids in beer using capillary electrophoresis is presented. In this work, malic, citric, succinic, pyruvic, acetic and lactic acids are separated using a sodium hydrogen phosphate background electrolyte with direct detection mode with a diode array detector. The separation exhibits lower sensitivity than equivalent methods with indirect detection mode, however, the risk of co-migration with unknown compounds in beer matrixes is significantly reduced. This is due to (i) a higher efficiency (250,000-400,000 theoretical plates), (ii) a higher selectivity than any equivalent method using an indirect detection mode, and (iii) the possibility to monitor other wavelengths in parallel (260 nm for example) to check for possible co-migration with phenolic or benzoic acids. This was critical when working with beer samples as an unknown compound absorbing at 200 and 260 nm was detected in the neighbourhood of malic, citric and succinic acids. Such co-migration will not have been detected using single wavelength detection below 200 nm or indirect detection mode.

关键词： Capillary electrophoresis diode array detection Organic acids in beer Polybrene

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Simultaneous Determination of Melamine and 5-Hydroxymethylfurfural in Milk by Capillary Electrophoresis with diode array detection

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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2009年第19期57卷 8742-8747页

作者： Chen, Zhijun Yan, Xiaomei Xiamen Univ Coll Chem & Chem Engn Key Lab Chem Biol Fujian Prov Key Lab Analyt SciDept Chem Biol Xiamen 361005 Peoples R China

This article describes the development of a simple analytical approach for the simultaneous determination of melamine and 5-hydroxymethylfurfural (HMF) in milk samples using capillary electrophoresis (CE) with diode array detection (DAD) for the first time. Ultraviolet absorption at wavelengths of 214 and 280 nm was applied for the detection of melamine and HMF, respectively. Milk samples were extracted with 1% trichloroacetic acid using a high-speed blender and ultrasonication. After centrifugation and filtration, the extract was analyzed by CE-DAD directly. Micellar electrokinetic capillary chromatography was employed as the separation mode by. adding sodium dodecyl sulfate (SDS) to the electrolyte. Under optimal. separation conditions, melamine, HMF, and interferents were well resolved. The linear dynamic ranges were 0.05-100 mu g/mL for melamine (R-2 = 0.9996) and 0.1-100 mu g/mL for HMF (R-2 = 0.9997). The assay detection limits were 0.047 mu g/mL and 0.067 mu g/mL for melamine and HMF, respectively. Satisfactory results were obtained for the assay recovery rate and repeatability. The proposed method was successfully applied for the analysis of melamine and HMF in real milk samples, and the results of melamine were comparable to those obtained using HPLC-UV reference method.

关键词： Melamine 5-hydroxymethylfurfural milk capillary electrophoresis diode array detection

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Comparison of Active Ingredient Content of Nanwuweizi and Beiwuweizi Collected in Different Seasons Detected by HPLC-DAD

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国际转化医学杂志（英文版） 2015年第4期3卷 258-262页

作者： YAO Feng CHEN Da-shuai Pharmacy of TCM Nanyang Second General Hospital Nanyang Henan 473012 China First Ward of Pediatric Department Nanyang Second General Hospital Nanyang Henan 473012 China

Objective:To compare the active ingredient content of Nanwuweizi (Kadsura longepedunculata) and Beiwuweizi (Fructus Schisandrae Chinensis) collected in different seasons.
Methods:Microwave-assisted extraction was applied to extract the active ingredients in Nanwuweizi and Beiwuweizi, with methanol as the solvent. High performance liquid chromatography-diode array detection (HPLC-DAD) method was used to analyze the content of each ingredient, with chromatographic conditions as follows: Brava BDS C18 column (250 mm×4.6 mm, 5 μm); column temperature: 30℃; mobile phase: water (A) - acetonitrile (B); gradient elution: 0.8 mL/min; and detection wavelength: 225 nm.
Results:All ingredients waiting for detection reached their peaks within 75 min, with excellent degree of separation and higher number of theoretical plates. Standard curves were drawn, and the mean value of phase relationship of each ingredient was >0.999. The content of active ingredients in lignans of Nanwuweizi and Beiwuweizi showed tendency of increase ifrst and then decreased. In addition, all ingredients in Beiwuweizi reached their peaks in September while those in Nanwuweizi in August.
Conclusion:This method can be used to detect the content of multiple ingredients in Wuweizi (Schisandra chinensis) simultaneously because it is simple in operation, precise in results and excellent in repeatability.

关键词： Nanwuweizi Beiwuweizi Lignan HPLC diode array detection Content determination

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Determination of orphenadrine plasma levels using HPLC with diode array detection and a novel solid-phase extraction procedure in psychiatric patients

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JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS 2009年第3期50卷 501-506页

作者： Saracino, M. A. Petio, C. Vitali, M. Franchini, L. Raggi, M. A. Univ Bologna Fac Pharm Dept Pharmaceut Sci Lab Pharmacotoxicol Anal I-40126 Bologna Italy Maggiore Hosp Dept Mental Hlth I-40133 Bologna Italy Residenza Socio Riabilitat Magnolia I-40100 Bologna Italy

Orphenadrine is an antimuscarinic agent mainly used for the treatment of parkinsonism and to alleviate the neuroleptic syndrome induced by antipsychotic drugs. A new, rapid analytical method, based on liquid chromatography with diode array detection (DAD), has been developed and applied to the determination of orphenadrine in plasma of schizophrenic patients for therapeutic drug monitoring and toxicological purposes. The chromatographic separation was performed on a pentafluorophenyl reversed phase column with a mobile phase composed of acetonitrile-phosphate buffer mixture. DAD detection was carried Out at 220 nm. A careful and rapid solid-phase extraction procedure on cyanopropyl cartridges was chosen for plasma sample purification and pre-concentration obtaining good extraction yield values for the analyte (>96.0%). The assays showed a linear response for orphenadrine (30-1000 ng mL(-1)). The method is also precise and selective. Thus, the method developed seems to be suitable for routine analysis of orphenadrine in psychiatric patients. Moreover, it was applied to plasma samples from a psychotic patient who had tried to poison himself with 1000 mg of orphenadrine and was undergoing polypharmacy. (C) 2009 Published by Elsevier B.V.

关键词： Orphenadrine Liquid chromatography diode array detection Solid-phase extraction Therapeutic drug monitoring Overdose

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A stability-indicating HPLC assay with diode array detection for the determination of a benzylpenicillin prodrug in aqueous solutions

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JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS 2009年第5期50卷 841-846页

作者： Jain, Rohit Wu, Zimei Tucker, Ian G. Bomac Labs Ltd Auckland New Zealand Univ Otago Sch Pharm Dunedin New Zealand

The aim of this study was to develop a stability-indicating HPLC assay for the determination of penethamate (PNT), an ester prodrug of benzylpenicillin (BP), in aqueous solutions. The method was validated by subjecting PNT to forced decomposition under stress conditions of acid, alkali, water hydrolysis and oxidation. A quenching solution was developed to limit degradation to negligible levels before and during the analysis. Both PNT and BP were simultaneously determined and separated in presence of degradation products on a C-18 column using a mobile phase consisting of methanol-acetonitrile-acetate buffer. Different degradation products were formed in the stress conditions. The peak purity indexes of PNT and BP obtained by diode array detection were >0.999, confirming the absence of other co-eluting substances. The assay was linear for both analytes in the concentration range 1-100 mu g mL(-1). The LOD and LOQ of PNT were 0.03 and 0.09 mu g mL(-1) respectively. Degradation of PNT followed pseudo-first-order kinetics with t(1/2) of 43.6 min at pH 2.01 and 4.2 min at pH 9.31. In addition, the absence of BP in the acidic solutions of PNT emphasises the futility of monitoring BP to assess the stability of PINT. In conclusion, the assay is rapid and stability-indicating with adequate precision and accuracy, and in conjunction with the quenching solution, can be used for stability studies of PNT with simultaneous quantitation of BP. The degradation studies provide useful information for formulation development of PNT. (C) 2009 Elsevier B.V. All rights reserved.

关键词： Penethamate Prodrug Stability-indicating reversed phase HPLC assay Hydrolysis Oxidation diode array detection

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Determination of five pesticides in juice, fruit and vegetable samples by means of liquid chromatography combined with multivariate curve resolution

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ANALYTICA CHIMICA ACTA 2014年 814卷 23-30页

作者： Boeris, Valeria Arancibia, Juan A. Olivieri, Alejandro C. Univ Nacl Rosario Fac Ciencias Bioquim & Farmaceut Dept Quim Analit RA-2000 Rosario Argentina Inst Quim Rosario IQUIR CONICET Rosario Argentina

The aim of this work was to quantify five commonly used pesticides (propoxur, carbaryl, carbendazim, thiabendazole and fuberidazole) in real samples as: tomato, orange juice, grapefruit juice, lemon and tangerine. The method used for the determination of these analytes in the complex matrices was high performance liquid chromatography with diode array detection. In order to work under isocratic conditions and to complete each run in less than 10 min, the analysis was carried out applying multivariate curve resolution coupled to alternating least-squares (MCR-ALS). The flexibility of this applied multivariate model allowed the prediction of the concentrations of the five analytes in complex samples including strongly coeluting analytes, elution time shifts, band shape changes and presence of uncalibrated interferents. The obtained limits of detection (in mu g L-1) using the proposed methodology were 2.3 (carbendazim), 0.90 (thiabendazole), 12 (propoxur), 0.46 (fuberidazole) and 0.32 (carbaryl). (C) 2014 Elsevier B.V. All rights reserved.

关键词： High-performance liquid chromatography diode array detection Multivariate curve resolution Pesticides Vegetable samples

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Direct determination of free bilirubin in serum at sub-nanomolar levels

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ANALYTICA CHIMICA ACTA 2014年第0期809卷 174-182页

作者： Martelanc, Mitja Ziberna, Lovro Passamonti, Sabina Franko, Mladen Univ Nova Gorica Environm Res Lab SI-5001 Nova Gorica Slovenia Univ Trieste Dept Life Sci I-34127 Trieste Italy

Direct analysis of free bilirubin in human and animal blood serum samples is reported for the first time. A state-of-the-art system comprised of newly developed high-performance liquid chromatography (HPLC) on reverse-phase (RP) C18 support coupled with thermal lens spectrometric detection (TLS), based on excitation at lambda = 457.9 nm by an argon laser was used for this purpose. This HPLC-TLS method enabled a baseline separation of all three structural isomers of bilirubin (XIII-alpha, IX-alpha and III-alpha) and the respective degradation products in isocratic mode in fewer than 7 min. The method excels in ultra-high sensitivity with limit of detection (LOD) and limit of quantitation (LOQ) of 90 pM and 250 pM, respectively. Moreover, this method also affords high precision and accuracy, with correlation coefficients R-2 > 0.997 over a broad linear range (0.250-150 nM) and R-2 = 0.9998 in a concentration range of clinical interest (0.500-25 nM). The method's boosted sensitivity enabled to streamline sample preparation to just one serum ultrafiltration step, which made qualitative evaluation of sample preparation possible for the first time. The performance of the HPLC-TLS method was assessed to have 20-fold enhanced sensitivity when compared to a comparable method incorporating HPLC coupled with diode array detector (DAD), which is also a novel method by itself, and could be applied for free bilirubin determination in patients with elevated bilirubin levels. (C) 2013 Elsevier B. V. All rights reserved.

关键词： Unbound and unconjugated bilirubin Human and animal blood serum High-performance liquid chromatography diode array detection Thermal lens spectrometry

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