Determination of 14 benzodiazepines and hydroxy metabolites, zaleplon and zolpidem as tert-butyldimethylsilyl derivatives compared with other common silylating reagents in whole blood by gas chromatography-mass spectrometry.
The most common commercially available silylating reagents, N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA), N,O-bis-(trimethylsilyl)trifluoroacetamide+1% trimethylchlorosilane (BSTFA+1% TMCS) and N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide (MTBSTFA) were evaluated to achieve optimal derivatization conditions for analyzing various benzodiazepines based on gas chromatography-electron impact ionization-mass spectrometry (GC-EI-MS). Sensitivity, repeatability, retention times and stability of the derivatives, as well as specificity of mass fragmentation, were studied in detail. Also other parameters affecting the derivatization chemistry of benzodiazepines are discussed. tert-Butyldimethylsilyl (TBDMS) derivatives proved to be more stable, reproducible and sensitive than corresponding trimethylsilyl (TMS) derivatives for the GC-EI-MS analysis of benzodiazepines. Based on the TBDMS derivatives, a rapid, reliable, sensitive and quantitative GC-MS method was developed for the determination of 14 benzodiazepines and two hydroxy metabolites, as well as two non-benzodiazepine hypnotic agents, zolpidem and zaleplon, using 50 microl of whole blood. The method was completely validated in terms of accuracy, intra- and interday precision, limit of detection (LOD), limit of quantitation (LOQ), linearity, selectivity and extraction efficiency; these were all within the required limits, except for the accuracy of nitrazepam at a medium concentration level.
Gunnar
Teemu
T
National Public Health Institute, Drug Research Unit, Mannerheimintie 166, 00300 Helsinki, Finland. teemu.gunnar@ktl.fi
Ariniemi
Kari
K
Lillsunde
Pirjo
P
D000081:Acetamides / Q000097:blood*; D001569:Benzodiazepines / Q000097:blood* / Q000302:isolation & purification; D004355:Drug Stability; D005463:Fluoroacetates; D008401:Gas Chromatography-Mass Spectrometry; D017646:Organosilicon Compounds / Q000032:analysis* / Q000737:chemistry; D011725:Pyridines / Q000097:blood*; D011743:Pyrimidines / Q000097:blood*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014269:Trifluoroacetic Acid / Q000737:chemistry; D014297:Trimethylsilyl Compounds / Q000737:chemistry; D000077334:Zolpidem
D000081:Acetamides; D005463:Fluoroacetates; D017646:Organosilicon Compounds; D011725:Pyridines; D011743:Pyrimidines; D014297:Trimethylsilyl Compounds; C009660:t-butyldimethylsilyl compounds; D001569:Benzodiazepines; C086665:N-methyl-N-(trimethylsilyl)trifluoroacetamide; C047270:N,N-bis(trimethylsilyl)-2,2,2-trifluoroacetamide; C039293:trimethylchlorosilane; C059151:N-methyl-N-(tert-butyldimethylsilyl)trifluoroacetamide; D000077334:Zolpidem; D014269:Trifluoroacetic Acid; C085665:zaleplon