SCREENING FOR FORENSICALLY RELEVANT BENZODIAZEPINES IN HUMAN HAIR BY GAS-CHROMATOGRAPHY NEGATIVE-ION CHEMICAL-IONIZATION MASS-SPECTROMETRY

A procedure is presented for the detection in human hair of forensical ly relevant benzodiazepines, i.e. nordiazepam, oxazepam, bromazepam, d iazepam, lorazepam, flunitrazepam, alprazolam and triazolam. The metho d involves decontamination of hair with methylene chloride, pulverizat ion in a ball mill, incubation of 50 mg powdered hair in Soerensen buf fer (pH 7.6) in the presence of prazepam-d(5) used as internal standar d, liquid-liquid extraction with diethyl ether-chloroform (80:20, v/v) and gas chromatography-mass spectrometry using negative chemical ioni zation after derivatization with N,O-bis(trimethylsilyl)trifluoroaceta mide plus 1% trimethylchlorosilane. The limits of detection for all be nzodiazepines ranged from 1 to 20 pg/mg using a 50-mg hair sample. Coe fficients of variation and extraction recoveries, ranging from 7.4 to 25.4% and 47.6 to 90%, respectively, were found suitable for a screeni ng procedure. One hundred and fifteen samples were submitted to this s creening procedure, and specimens tested positive for nordiazepam (0.2 0-18.87 ng/mg, n=42) and its major metabolite oxazepam (0.10-0.50 ng/m g, n=14), flunitrazepam (19-148 pg/mg, n=31), lorazepam (31-49 pg/mg, n=4) and alprazolam (0.3-1.24 ng/mg, n=2). Bromazepam, diazepam and tr iazolam were not detected. (C) 1997 Elsevier Science B.V.