Simultaneous hair testing for opiates, cocaine, and metabolites by GC-MS: a survey of applicants for driving licenses with a history of drug use

A sensitive GC-MS method for the simultaneous determination of opiates, coc aine, and metabolites in hair at a cut-off level of 0.1 ng/mg was adopted t o assess past exposure to these drugs in applicants for driving Licenses wi th a history of drug use. The sampling protocol consisted of collection of one hair (sample A, 5-cm length) and one urine sample. When hair and urine (EMIT(R) Syva, cut-off levels: 0.3 mg/l for opiates, 0.15 mg/l for cocaine, GC-MS confirmation of positives) were both positive or negative the protoc ol was concluded. In the other cases, the assessment of 'current exposure' to drugs was carried out, in order to avoid seriated random urinalysis, by collecting a second hair sample (sample B) 6 weeks later and analysing the proximal l-cm segment. Out of the 214 'A' hair samples analyzed, 14 (6.5%) tested positive for morphine and/or B-acetylmorphine (6AM), and 26 (12%) fo r cocaine and/or benzoylecgonine (BE), whereas none of the samples tested p ositive for both drugs. Levels between 0.1 and 1 ng/mg of the single analyt es were found in eight out of the 14 morphine-6AM positives (57%) and in 18 out of the 26 cocaine-BE positives (69%). The time course of positive case s showed a progressive decrease of morphine-6AM positives and a correspondi ng increase of cocaine-BE positives within the study period September 1995- February 1999. No cases with positive urine and negative hair were observed . Among the 40 positive cases, seven (four and three for opiates and cocain e, respectively) were found to be 'currently exposed to drug', four by urin alysis (three and one) and three by analysis of the hair sample B (1 and 2) . (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.