Liquid-phase microextraction as a sample preparation technique prior to capillary gas chromatographic-determination of benzodiazepines in biological matrices

Liquid-phase microextraction (LPME) and gas chromatography were applied to determine diazepam and the main metabolite N-desmethyldiazepam in human urine and plasma. The analytes were extracted from 3.0–3.5 ml sample volumes directly into 25 μl of extraction solvent. The microextraction device consis...

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Bibliographic Details
Published in:Journal of chromatography. B, Biomedical sciences and applications Biomedical sciences and applications, 2000-11, Vol.749 (1), p.85-92
Main Authors: Ugland, Hege Grefslie, Krogh, Mette, Rasmussen, Knut E
Format: Article
Language:English
Subjects:
Analysis
Benzodiazepines
Biological and medical sciences
Chromatography, Gas - methods
Diazepam - analysis
Diazepam - blood
Diazepam - urine
General pharmacology
Humans
Medical sciences
Nordazepam - analysis
Nordazepam - blood
Nordazepam - urine
Pharmacology. Drug treatments
Reproducibility of Results
Sensitivity and Specificity
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Summary:Liquid-phase microextraction (LPME) and gas chromatography were applied to determine diazepam and the main metabolite N-desmethyldiazepam in human urine and plasma. The analytes were extracted from 3.0–3.5 ml sample volumes directly into 25 μl of extraction solvent. The microextraction device consisted of a porous hollow fiber of polypropylene attached to two guiding needles inserted through a septum and a 4 ml vial. The hollow fiber filled with extraction solvent was immersed in sample solution. The extraction device was continuously vibrated at 600 rpm for 50 min. An aliquot (1 μl) of the extraction solvent with preconcentrated analytes was injected directly into the capillary gas chromatograph. Thirty samples were extracted simultaneously on the vibrator, providing a high sample capacity. The limits of detection were from 0.020 to 0.115 nmol/ml for diazepam and N-desmethyldiazepam in plasma and urine using a nitrogen–phosphorus detector (NPD).
ISSN:0378-4347
1387-2273
DOI:10.1016/S0378-4347(00)00382-0