CAPILLARY ELECTROPHORESIS FOR THE INVESTIGATION OF ILLICIT DRUGS IN HAIR - DETERMINATION OF COCAINE AND MORPHINE

Toxicological analysis of hair is becoming a popular method for invest igating past, chronic use of illicit drugs. Several analytical methods using immunometry, chromatography and mass spectrometry have been rep orted. In this work, capillary electrophoresis was first used for the determination of illicit drugs, such as cocaine and morphine, in the h air of heroin and cocaine users. After rapid washing, hair samples wer e incubated overnight in 0.25 M HCl at 45-degrees-C and the mixtures w ere extracted with ready-to-use Toxi-tubes A. The organic phase was ev aporated and the residue dissolved in a suitable amount of electrophor esis buffer. Free zone capillary electrophoretic determinations of mor phine, the main heroin metabolite, and cocaine were accomplished in 0. 05 M borate buffer (pH 9.2) at a potential of 15 000 V, with UV detect ion at 214 and 238 nm, respectively. The use of the less selective wav elength of 200 nm allowed the simultaneous detection of both compounds . Efficient separations (up to 350 000 theoretical plates) and accurat e and precise determinations (intra-day R.S.D.s in the range 3-5%) of cocaine and morphine in hair extracts were easily achieved. The analyt ical sensitivity was sufficient to determinate as little as 0.15 ng/mg of cocaine and morphine in hair using 100-mg samples. Interferences f rom more than 90 therapeutic drugs and drugs of abuse were excluded.