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Analysis of aminopyridines and diaminopyridines by capillary electrophoresis

CHROMATOGRAPHIA 2001年第9-10期53卷 559-562页

作者： Sabbah, S Abu-Khurmah, M Oelschläger, H Scriba, GKE Univ Jena Dept Pharmaceut Chem Sch Pharm D-07743 Jena Germany

A capillary electrophoresis method was developed for the separation of aminopyridines and diaminopyridines. The influence of the buffer pH and type of buffer was studied. Optimum separation conditions were 100 mM sodium acetate buffer, pH 5.15, and an applied voltage of 20 kV using a capillary of 50 cm effective length. In addition to use of the migration times the compounds could be identified by their UV spectra when using a DAD detector The assay was applied to the analysis of 3,4-diaminnopyridine.

关键词： capillary electrophoresis diode array detection aminopyridine diaminopyridine

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Characterisation of polar organic compounds in fog water

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ATMOSPHERIC ENVIRONMENT 2001年第12期35卷 2193-2200页

作者： Kiss, G Varga, B Gelencsér, A Krivácsy, Z Molnár, A Alsberg, T Persson, L Hansson, HC Facchini, MC Univ Veszprem Hungarian Acad Sci Air Chem Grp H-8201 Veszprem Hungary Univ Veszprem Dept Earth & Environm Sci H-8201 Veszprem Hungary Stockholm Univ Inst Appl Environm Res SE-106916 Stockholm Sweden CNR Ist Sci Atmosfera & Oceano I-40129 Bologna Italy

In this paper the results of a systematic liquid chromatographic investigation are described to characterise water-soluble organic compounds in fog. A diode array detector is used to record the UV spectrum of the components during separation and a mass spectrometer is applied to obtain information on the ion masses of the constituents. The combination of UV acid mass spectra reveal that the organic carbon content of fog water is distributed among a great number of acidic compounds which have polar functional groups and polyconjugated systems absorbing up to 500 nm. Due to the complexity of the organic fraction in fog water an unresolved hump of ions was recorded by the mass spectrometer From m/z = 100-600 the most intense peaks being detected around m/z = 200-250. Tannin and fulvic acid were also examined under the same conditions. In terms of complexity and ion distribution the mass spectrum of the organic fraction was similar to that of a fulvic acid reference material rather than to that of tannin. (C) 2001 Elsevier Science Ltd, All rights reserved.

关键词： water-soluble organic compounds fog liquid chromatography mass spectrometry diode array detection

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Simultaneous determination of benzodiazepines in whole blood or serum by HPLC/DAD with a semi-micro column

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JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS 2000年第2-3期23卷 447-458页

作者： El Mahjoub, A Staub, C Inst Univ Med Legale CH-1211 Geneva 4 Switzerland

A simple and sensitive high performance liquid chromatographic (HPLC) method using a semi-micro column, C-8 reversed-phase column (3 mm i.d.) and a low flow rate 0.3 ml/min was developed and validated for the determination of five frequently prescribed benzodiazepines: clonazepam, diazepam. flunitrazepam, midazolam and oxazepam. Quantification was performed at 220 nm with methylclonazepam as internal standard. The method involved a simple extraction fi om alkalinized blood (1 mi) into 1-chlorobutane and provided excellent sensitivity, recovery, accuracy and reproducibility for benzodiazepines in therapeutic or toxic concentrations. (C) 2000 Elsevier Science B.V. All rights reserved.

关键词： benzodiazepines blood diode array detection high performance liquid chromatography serum semi-micro HPLC column

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Determination of pongamol and karanjin in karanja oil by reverse phase HPLC

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ANALYTICAL LETTERS 2000年第2期33卷 337-346页

作者： Gore, VK Satyamoorthy, P Hindustan Lever Res Ctr Mumbai 400099 India

Pongamol and karanjin, naturally present in karanja (Pongamia glabra) oil possess potential UV A and UV B sunscreen activities, respectively. A reverse phase high performance liquid chromatography (RP-HPLC) method has been developed for direct estimation of these constituents of karanja oil. This method of analysis requires no sample preparation of active ingredients. The analysis uses methanol, water and acetic acid in the ratio of 85: 13.5: 1.5 as mobile phase at a flow rate of 0.5 ml/ min on a Kromasil 100 C18 column, ex Tracer (250mm X46mm, particle size 5 microns) and dual wavelength detection at 350 and 300 nm. 2-ethylhexyl-p-methoxy cinnamate (Parsol MCX) was used as the internal standard. The identical UV spectrum of the chromatographic region (upslope, apex and downslope) confirmed that the analysis was free from substrate interference. The detection limits for pongamol and karanjin were found to be 0.1 mu g / ml.

关键词： pongamol karanjin karanja oil RP-HPLC sunscreen activity diode array detection

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Multiresidue HPLC methods for phenyl urea herbicides in water

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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2000年第9期48卷 4109-4115页

作者： Ruberu, SR Draper, WM Perera, SK Calif Dept Hlth Serv Sanitat & Radiat Lab Berkeley CA 94704 USA

High-performance liquid chromatography (HPLC) methods for the determination of phenyl urea herbicides in water are described. The target compounds include chlortoluron, diuron, fluometuron, isoproturon, linuron, metobromuron, metoxuron, monuron, neburon, and siduron. Water was subjected to solid phase extraction (SPE) using either automated SPE with 47 mm C-18 Empore disks or on-line precolumn concentration. Herbicides were separated on a C18 reversed phase column with an acetonitile-water gradient and were detected with either a diode array detector (DAD) or a postcolumn photolysis and derivatization (PPD) detector system. Photolysis converted the phenyl ureas to monoalkylamines that were derivatized to fluorescent isoindoles by reaction with o-phthalaldehyde and a-mercaptoethanol. The DAD monitoring at 245 nm was linear over three decades with instrument detection limits of similar to 0.01 mg/L. SPE efficiency was between 48 and 70% in laboratory reagent water, but use of the internal standard quantitation method improved accuracy. High total dissolved solids and total organic carbon values in surface water improved recoveries relative to laboratory reagent water for all of the phenyl ureas. In Colorado River water spiked at 1 or 50 mu g/L, mean recoveries ranged from 74 to 104%. Method detection limits (MDLs) ranged from 4 to 40 ng/L (parts per trillion) with the DAD instrument. PPD detection was highly specific but resulted in a slight loss in chromatographic efficiency and average MDLs similar to 5 times higher using a single set of detection conditions. The study indicates that methods based on SPE followed by HPLC with diode array or PPD detection have practical utility for trace analysis of phenyl ureas in drinking water or surface waters.

关键词： phenyl urea herbicides analysis water solid phase extraction (SPE) diode array detection postcolumn photolysis and derivatization detection

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Comparison of in-line connected diode array and electrochemical detectors in the high-performance liquid chromatographic analysis of coenzymes Q₉ and Q₁₀ in food materials

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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2000年第4期48卷 1229-1233页

作者： Mattila, P Lehtonen, M Kumpulainen, J Agr Res Ctr Finland L-Talo Jokioinen 31600 Finland

In-line connected electrochemical (EC) and diode array (DAD) detectors were compared in the reversed-phase high-performance liquid chromatographic (RP-HPLC) analysis of coenzymes Q(9) and Q(10) in some food materials (beef steak, beef heart, Baltic herring fillet, and rye flour). Coenzymes Q(9) and Q(10) were extracted from the samples using a 5:1 n-hexane-ethanol mixture. Coefficient of variation (CV%) of quadruplicate or quintuplicate determined samples for coenzymes Q(9) and Q(10) was < 10 by both EC detector and DAD. Responses of the detection systems were linear in the range evaluated, 10-200 ng/injection, and had correlation coefficients exceeding 0.999. Recoveries of added coenzymes Q(9) and Q(10) varied 73-105% for DAD and 74-103% for EC detector, respectively. detection limits for coenzymes Q(9) and Q(10) using the DAD system were 4 and 6 ng/injection, respectively, and 0.2 and 0.3 ng/injection by EC detection. Results derived from the two detection systems were generally similar. However, although EC detector was 20-fold more sensitive, the selectivity was, in some cases, poorer than that of DAD.

关键词： coenzyme Q(9) coenzyme Q(10) ubiquinone HPLC electrochemical detection diode array detection food analysis

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Use of simulated liquid chromatography diode array detection data for the definition of a guide curve in peak purity assessment by spectral comparison

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JOURNAL OF CHROMATOGRAPHY A 1997年第1期786卷 1-11页

作者： Gilliard, JA Ritter, C LAB SIMON B-1301 WAVREBELGIUM UNIV CATHOLIQUE LOUVAIN INST STATB-1348 LOUVAINBELGIUM

Computing dissimilarity profiles between spectra within a chromatographic peak and comparing them to a base profile for a pure peak can be a sensitive method for detecting coelution. The power of this method is limited by noise and non-idealities. For high maximum absorbances, non-idealities prevail over noise. In current practice, either the maximum absorbances are limited, or the base profile is computed from injections of pure standards. The first approach leads to a loss in detection power, the second requires substantial extra work, since the standards have to be obtained and they have to be measured separately for each peak of interest in the chromatogram. Here, we show that an approximation to the base profile can be computed from realistic simulations of homogeneous data accounting for potential non-idealities. This is demonstrated using several graphical displays. As a result, higher maximum absorbances leading to better impurity detection can be used without extra experimentation. (C) 1997 Elsevier Science B.V.

关键词： peak purity computer simulation diode array detection detection, LC alprazolam triazilam hydrochlorothiazide

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Determination of organophosphorus pesticides and metabolites in crops by solid-phase extraction followed by liquid chromatography diode array detection

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CHROMATOGRAPHIA 1997年第5-6期46卷 256-264页

作者： Lagana, A DAscenzo, G Fago, G Marino, A Department of Chemistry “La Sapienza” Rome Italy

A multiresidue method for the analysis of 28 common organophosphorus pesticides and 3 of their main metabolites (paraoxon-ethyl, paraoxon-methyl and malaoxon) in a variety of crop samples has been developed. An aliquot of the chopped sample is homogenized with an organic solvent. The efficiency of extraction methods using methanol, acetone and acetonitrile was evaluated. The acetonitrile gives higher recoveries and minimizes co-extractives from the samples matrix. The resulting aqueous acetonitrile extract is filtered and cleaned by solid phase extraction (SPE). For SPE three different types of adsorption materials (Carbograph 1, LiChrolut-EN and Amberchrom CG-161m) were compared. The cleaned-up extract is injected into the LC system. Three different analytical columns were tested in conjunction with two mobile phase compositions of different polarity. The use of LC-DAD techniques allowed the identification of both organophosphorus pesticides and metabolites by means of standard and spectral comparison, respectively. The accuracy of the quantitative determination measured in terms of average percentage recovery of 31 compounds in crop samples was 61-96 % with a relative standard deviation of 5-10 %.

关键词： column liquid chromatography diode array detection solid phase extraction phosphorus pesticide residue analysis crop samples

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Acidic and neutral drugs screen in blood with quantitation using microbore high-performance liquid chromatography diode array detection and capillary gas chromatography flame ionization detection

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FORENSIC SCIENCE INTERNATIONAL 1997年第3期90卷 205-214页

作者： Lo, DST Chao, TC Ng-Ong, SE Yao, YJ Koh, TH Inst Sci & Forens Med Singapore 169078 Singapore

Blood previously acidified with aqueous saturated ammonium chloride solution was extracted with ethyl acetate. The dried extract was subjected to acetonitrile-hexane partition. The acetonitrile portion was analysed for the presence of acidic and neutral drugs by HPLC-DAD (200 mmX2.1 mm I.D. microbore ODS-Hypersil column) and GC-FID (25 m narrow-boreX0.25 mm I.D. HP-5 column with 0.33 mu m film thickness). The protocol was found to be suitable for both clinical toxicology (including emergency toxicology) and postmortem toxicology. At least 66 drugs of interest were unequivocally identified by RRTs (HPLC) and UV spectra (DAD) match while another 12 were unequivocally identified by double RRTs match (HPLC and GC). Quantitation was facilitated by incorporating calibration blood standards in each assay batch. The five drugs most commonly encountered in clinical blood specimens (1150 cases) were: paracetamol (47.4% of the cases);chlormezanone (6.6%), theophylline (1.74%), naproxen (1.65%) and mefenamic acid (1.56%). The following drugs were detected in toxicologically significant quantities in postmortem blood specimens (245 cases): phenobarbitone (1.22% of the cases), naproxen (0.82%), chlormezanone (0.82%), theophylline (0.82%), carbamazepine (0.41%) and paracetamol (0.41%). (C) 1997 Elsevier Science Ireland Ltd.

关键词： high performance liquid chromatography diode array detection acidic drugs neutral drugs blood

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Identification of organic colourants in cosmetics by HPLC diode array detection

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CHROMATOGRAPHIA 1997年第1期45卷 215-228页

作者： Rastogi, SC Barwick, VJ Carter, SV LAB GOVT CHEMIST TEDDINGTON TW11 0LY MIDDX ENGLAND

A method for the analysis of organic cosmetic colourants was developed. The colourants extracted from the cosmetic products were analysed by HPLC followed by diode-array detection across the wavelength range 275 nm-760 nm. The chromatographic separation was performed on a column with a polymeric packing using gradient elution with a mobile phase composed of citrate buffer, the ion-pairing reagent tetrabutylammonium hydroxide, acetonitrile and tetrahydrofuran. The colourants were identified on the basis of their retention times as well as their UV-visible spectra. A spectral library consisting of retention times and UV-visible spectra of 130 organic cosmetic colourants has been built for the purpose of identifying of colouring matter in cosmetic products. Solid-phase extraction methods using;C-18 silica and aminobonded silica have been developed for the extraction of colourants from various types of cosmetic products. The method for the identification of colourants in nail varnishes and lipsticks has been optimized for routine analysis.

关键词： column liquid chromatography solid phase extraction diode array detection UV-visible spectral library cosmetics colourants

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