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Simultaneous determination of flunitrazepam and its metabolites in plasma and urine by HPLC/DAD after solid phase extraction

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JOURNAL OF PHARMACEUTICAL AND BIOMEDICAL ANALYSIS 1997年第4期16卷 707-715页

作者： He, WD Parissis, N State Univ Ghent Dept Organ Chem Toxicol Lab B-9000 Ghent Belgium

A high performance liquid chromatography (HPLC) assay was developed for the determination of flunitrazepam (FNZ) and its metabolites in urine and plasma. The analytes and the internal standard (triazolam, TRZ) were extracted by Sep-Pak C18 SPE-cartridge and separated utilizing a 5 mu m ChromSpher C8 glass column with a gradient mobile phase containing methanol and 0.125% (v/v) of isopropylamine in water. diode array detection (DAD) was carried out at a monitoring wavelength of 240 nm and a reference wavelength of 550 nm. Standard curves were linear from their quantitation limits until 200 ng ml(-1) urine or 250 ng ml(-1) plasma for 7-amino-desmethyl-flunitrazepam (ADF), 7-amino-flunitrazepam (AF), 7-acetamino-flunitrazepam (ACF) and until 400 ng ml(-1) urine or 500 ng ml(-1) plasma for FNZ, 1-desmethyl-flunitrazepam (DF), and 3-hydroxyl-flunitrazepam (HF). The intraday and interday coefficients of variation ranged from 2.04 to 9.07% and from 2.64 to 14.10%, respectively in urine and from 5.13 to 8.60% and from 7.27 to 10.46%, respectively in plasma. The developed method is used in forensic toxicology and is also applicable to pharmacokinetic studies in man. (C) 1997 Elsevier Science B.V.

关键词： flunitrazepam metabolite high performance liquid chromatography diode array detection solid phase extraction urine plasma

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Fully automated on-line supported liquid membrane liquid chromatographic determination of aniline derivates in environmental waters

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CHROMATOGRAPHIA 1997年第9-10期46卷 483-488页

作者： Norberg, J Zander, A Jonsson, JA LUND UNIV DEPT ANALYT CHEMS-22100 LUNDSWEDEN

The potential of an on-line combination of supported liquid membrane extraction and liquid chromatography for the determination of aniline derivatives in environmental water samples has been investigated. Seven aniline derivatives (aniline, 4-chloroaniline, 2-chlororaniline, 4-chloro-2-methylanline, 3-chloro-2-methylaniline, 2-chloro-4-methylaniline and 3,5-dichloroaniline), covering a wide range in polarity and in dissociation constants, were chosen as model compounds. Calibrations were linear in the 0.1-1 mu g L-1 range, with good correlation coefficients (r > .997). detection limits were in the range 0.005-0.015 mu g L-1. The total analysis time of the system is 44 min, determined by the liquid chromatographic separation and equilibration times.

关键词： column liquid chromatography supported liquid membrane diode array detection aniline derivatives

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HPLC determination of pesticides in green bean samples after SPE clean-up

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CHROMATOGRAPHIA 1996年第5-6期43卷 265-270页

作者： Parrilla, P Vidal, JLM UNIV ALMERIA FAC EXPT SCIDEPT ANALYT CHEMALMERIA 04120SPAIN

A reversed-phase high performance liquid chromatographic (HPLC) method with an acetonitrile-methanol-water mobile phase gradient and photodiode-array detection (DAD) is described for simultaneous determination of 21 pesticides, frequently used in agriculture, of different types, namely organophosphorus, organochlorine, N-methylcarbamates, triazines and phenylureas in vegetable samples. The pesticides were extracted with acetone and then partitioned from the vegetable sample with dichloromethane. Sample cleanup was accomplished by solid-phase extraction (SPE) using both C-18 and florisil SPE columns. Average recoveries from green beans ranged from 70.0 to 110.1 %. detection limits of less than 0.1 mg kg(-1) were obtained.

关键词： column liquid chromatography diode array detection solid-phase extraction (SPE) pesticide analysis multiresidue methods green bean samples

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Analysis of clobazam and its active metabolite norclobazam in plasma and serum using HPLC/DAD

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SCANDINAVIAN JOURNAL OF CLINICAL & LABORATORY INVESTIGATION 1996年第7期56卷 609-614页

作者： Akerman, KK UNIV KUOPIO DEPT CLIN CHEMSF-70210 KUOPIOFINLAND

This report describes a simple reversed-phase high-performance liquid chromatographic (HPLC) method with automated solid-phase extraction (SPE) for analysing clobazam and norclobazam concentrations in human serum or plasma. For the HPLC analysis the samples and standards are prepared with an ASPEC automatic sample preparer using 100-mg Bond-Elut C-18 solid-phase extraction columns. The HPLC method is an isocratic method with a mobile phase of acetonitrile :methanol: 10 mmol l(-1) dipotassium hydrogen phosphate, pH 3.7 (30:2:100), at a flow rate of 1.5 ml min(-1). The benzodiazepines are detected with a diode array detector (DAD) at 240 nm and the peak purity analyses are performed at 210-365 nm. The recovery is over 97% for both analytes, and it is independent of the drug concentration. The intra-assay CVs vary between 0.7 and 2.2% and inter-assay CVs between 3.8 and 4.6% at therapeutic drug concentrations. The detection limit is 15 nmol l(-1). The assay is linear from 30 to 20 000 nmol l(-1) (clobazam) and from 170 to 105 000 nmol l(-1) (norclobazam). This method leads to a very good separation of norclobazam from carbamazepine and phenytoin. None of the anti-epileptic or antidepressant drugs tested interfere with the assay.

关键词： diode array detection clobazam high-performance liquid chromatography (HPLC) norclobazam solid-phase extraction (SPE) therapeutic drug monitoring (TDM)

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SIMULTANEOUS DETERMINATION AND CONFIRMATION OF SODIUM N-METHYLDITHIOCARBAMATE [METHAM SODIUM(R)] AND METHYL ISOTHIOCYANATE IN WATER BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH diode-array detection

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INTERNATIONAL JOURNAL OF ENVIRONMENTAL ANALYTICAL CHEMISTRY 1993年第3期53卷 165-171页

作者： DHOOT, JS DELROSARIO, AR TAMPLIN, BR California State Department of Health Services Division of Laboratories Sanitation and Radiation Laboratory 2151 Berkeley Way Room 465 Berkeley CA 94704 USA

A high performance liquid chromatographic (HPLC) procedure was developed for determination and confirmation of sodium N-methyldithiocarbamate and methyl isothiocyanate (MITC) present in water. Both analytes are separated on a strong anion exchange column (25 cm x 4.6 mm x 5 mum) with a mobile phase of (45+55, V/V) methanol/buffered water (pH 6.9) containing 10mM hexadecyltrimethyl ammonium bromide (CTAB) and are measured by UV using 242 and 284 nm wavelengths. diode array spectra were acquired for confirmation. Analyte recoveries were 108% and 114%, respectively when both compounds were present in raw surface water. Linear calibration plots from 5 mug/L to 250 mg/L for MITC and 5 mg/L to 250 mg/L for Metham Sodium(R) with correlation coefficients of >0.99, were obtained. Precision data and analyte UV/VIS spectra for confirmation are shown for both compounds. The detection limit is 2 mug/L for MITC and 2 mg/L for Metham Sodium(R).

关键词： SODIUM N-METHYLDITHIOCARBAMATE METHYL ISOTHIOCYANATE diode array detection HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

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LIBRARY SEARCH FOR HPLC diode-array detection BASED ON SPECTRAL INTERPOLATION

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CHROMATOGRAPHIA 1993年第1-2期37卷 31-36页

作者： DATHE, B OTTO, M 1. Department of Chemistry Institute of Analytical Chemistry Bergakademie Freiberg Leipziger Stra?e 29 9200 Freiberg/Sachsen Germany

A new method for spectral library search based on the dependences of absorbance on the modifier contents in binary mobile phases was developed. The normalisation of spectra by absolute and relative maximum and with respect to the area was tested. The correlation coefficient and the Euclidian distance were used to compare the spectra. The new method of library search allows interpolation of spectra at every composition of eluent in the model range. The range is bracketted by the upper and lower content of modifier in the eluent. In this range five reference spectra were recorded. For validation 34 spectra of pharmaceutical substances in water/methanol and water/acetonitrile mixtures were recorded. In the best case 97 % of spectra were identified correctly. The main problems encountered are that very similar substances e.g. dexa- and betamethasone, have similar spectra as well as similar spectral dependences on the composition of the mobile phase.

关键词： COLUMN LIQUID CHROMATOGRAPHY diode array detection UV LIBRARY SEARCH PHARMACEUTICAL COMPOUNDS

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Analysis of selected mycotoxins by capillary electrophoresis

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CHROMATOGRAPHIA 1995年第11-12期41卷 631-637页

作者： Bohs, B Seidel, V Lindner, W Institut für Pharmazeutische Chemie Karl-Franzens-Universität Graz Graz Austria Hafslund Nycomed Pharma AG. Linz Austria

The separation of the mycotoxins ochratoxin A, ochratoxin B, zearalenone and moniliformin by standard capillary zone electrophoresis (CZE) and cyclodextrins modified CE is described. In addition, reversed electroosmotic flow (EOF) conditions via quarternary ammonium running buffer additives have been briefly examined. Parameters influencing selectivity and mobility as well as spectroscopic properties of the analytes have also been investigated. Separations performed at pH values from 5 to 11 show a marked pH dependency of the mobilities accompanied by pronounced shifts of the UV/VIS and/or fluorescence spectra of the compounds. In general, the on-line recording of spectra by diode-array detection (DAD), proved to be highly versatile for peak tracking simultaneously with the structure elucidation and thus for the optimization of sample introduction, peak resolution and detection conditions.

关键词： capillary electrophoresis mycotoxins selective analysis development diode array detection cycle dextrin-modified CE

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A COMPUTER-CONTROLLED CONTINUOUS DILUTION DILATOMETER FOR THE DETERMINATION OF SOLUTE MOLAR VOLUMES AND DIRECT MEASUREMENT OF REACTION VOLUMES IN SOLUTION

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JOURNAL OF SOLUTION CHEMISTRY 1995年第8期24卷 795-811页

作者： JOHNSTONE, S SACHINIDIS, JI SHALDERS, RD TREGLOAN, PA School of Chemistry The University of Melbourne Parkville Australia

The design and operation of a computer controlled continuous dilution dilatometer utilizing a diode array detection system is presented. To test the accuracy and reproducibility of the technique, apparent molar volumes of dilute aqueous solutions of potassium ferricyanide and potassium ferrocyanide have been measured. To provide supporting data for high pressure studies of reaction volumes and molar volume change in solutions of high ionic strength, study of these electrolytes was extended by dilution into 0.1M and 1.0M potassium nitrate solutions rather than extrapolation to zero ionic strength as is normal. In addition, the system has been used to determine reaction volumes of some acid-base reactions by direct measurement, using the equipment as an automatic titration dilatometer.

关键词： MOLAR VOLUME REACTION VOLUME DILATOMETRY diode array detection K3FE(CN)(6) K4FE(CN)(6) HN3

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PARALLEL KALMAN FILTERS FOR PEAK PURITY ANALYSIS - EXTENSIONS TO NONIDEAL DETECTOR RESPONSE

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ANALYTICA CHIMICA ACTA 1995年第2-3期307卷 459-470页

作者： WENTZELL, PD HUGHES, SG VANSLYKE, SJ Trace Analysis Research Centre Department of Chemistry Dalhousie University Halifax NS B3H 4J3 Canada

A mathematical method for detecting spectral impurities in liquid chromatographic peaks measured with a diode array detector (LC-DAD) is described. The new method compensates for certain measurement non-idealities, minimizing the likelihood of a false indication of an impurity. The algorithm, evolving projection analysis, is based on a previously reported method in which points in an n-dimensional absorbance space (n = number of wavelengths) are projected onto two-dimensional subspaces and modeled using the Kalman filter. Model deviations can be indicative of the presence of spectral impurities, or may result from measurement artifacts such as heteroscedastic noise or non-linear detector response. The modified algorithm incorporates model variants that mask the effects of heteroscedastic noise and non-linearities so that impurities can be detected even in the presence of these artifacts. A noise model is developed for the DAD and simulations are used to evaluate the modified algorithm. Simulations are validated through the use of experimental data. It is demonstrated that, except in cases where the effects of non-linearities become severe, the modified model successfully compensates for these measurement non-idealities.

关键词： diode array detection KALMAN FILTER LIQUID CHROMATOGRAPHY NONIDEAL DETECTOR RESPONSE PEAK PURITY UV-VISIBLE SPECTROPHOTOMETRY

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DECONVOLUTION AND QUANTITATION OF UNRESOLVED MIXTURES IN LIQUID-CHROMATOGRAPHIC - diode-array detection USING EVOLVING FACTOR-ANALYSIS

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CHROMATOGRAPHIA 1992年第5-6期33卷 244-254页

作者： TAULER, R DURAND, G BARCELO, D CSIC CIDDEPT ENVIRONM CHEMC JORDI GIORNA 18-26E-08034 BARCELONASPAIN UNIV BARCELONA DEPT ANALYT CHEME-08028 BARCELONASPAIN

A recently developed self-modeling curve resolution method based in different factor analysis techniques has been applied for the first time to the study of liquid-chromatography-diode array data under situation where the separation of two components is not achieved. Two applications are reported: the resolution and quantitation of a coeluted mixture of carbamate pesticides pirimicarb and 1-naphthol, and the estimation of the concentration profiles of the double peak obtained in the elution of the triazine metabolite chlorodiamino-s-triazine. Different methods of quantitation are compared, including Evolving Factor Analysis and Rank annihilation. Quantitation from the area of the elution profiles once the component spectra have been transformed for their area contribution to the signal, gives a relative composition for pirimicarb and naphthol pesticides which agrees with the known sample composition. In the case of the unknown triazine mixture, an approximate quantitation of the two peaks obtained for this metabolite is obtained by assuming equal signal contribution or equal maximum absorbance of the individual spectra of the two detected components.

关键词： COLUMN LIQUID CHROMATOGRAPHY diode array detection PRINCIPAL COMPONENT ANALYSIS EVOLVING FACTOR ANALYSIS PESTICIDE MIXTURES

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