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Fast gas chromatography–negative‐ion chemical ionization mass spectrometry with microscale volume sample preparation for the determination of benzodiazepines and α‐hydroxy metabolites, zaleplon and zopiclone in whole blood
Author(s) -
Gunnar Teemu,
Ariniemi Kari,
Lillsunde Pirjo
Publication year - 2006
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.1030
Subject(s) - chemistry , chromatography , sample preparation , mass spectrometry , chemical ionization , gas chromatography , extraction (chemistry) , analyte , analytical chemistry (journal) , bromazepam , gas chromatography–mass spectrometry , oxazepam , ionization , ion , benzodiazepine , biochemistry , receptor , organic chemistry
Fast gas chromatography/negative‐ion chemical ionization mass spectrometric (GC/NICI‐MS) assay combined with rapid and nonlaborious sample preparation is presented for the simultaneous determination of benzodiazepines and α‐hydroxy metabolites, zaleplon and zopiclone in whole blood. The compounds were extracted from 100 µl of whole blood by simultaneous multitube, microscale liquid‐liquid extraction (LLE) and derivatized by N ‐methyl‐ N ‐( tert ‐butyldimethylsilyl)trifluoroacetamide (MTBSTFA), without the need for the time‐consuming concentration stage. In the analytical separation, various parameters of fast GC/NICI‐MS were applied, e.g. the use of hydrogen as a GC carrier gas, a high carrier gas velocity, a small film thickness of the analytical column, fast MS data acquisition, fast temperature ramping, and high initial and final temperatures of GC column. Sensitive identification, screening and quantitation of 18 compounds of interest were achieved in chromatographic separation in only 4.40 min. Accurate and reproducible results were obtained by using five different and carefully selected deuterated analogues on the basis of the chemical properties of the target analytes. Nevertheless, for α‐OH‐midazolam, and for bromazepam and flunitrazepam at low concentrations, the results can be considered only semiquantitative on the basis of the validation data. The extraction efficiencies ranged from 74.3 to 105.7% and the limits of quantitation (LOQ) from 1 to 100 ng ml −1 . Rapid sample preparation and fast chromatographic separation allowed cost‐efficient, reliable and high sample‐throughput analyses with a low amount of manual work. The method was fully validated and accredited according to EN ISO/IEC 17025 standards and is applicable for sensitive, reliable and quantitative determination of benzodiazepines, zaleplon and zopiclone, e.g. in clinical and forensic toxicology. Copyright © 2006 John Wiley & Sons, Ltd.