RESUMEN
Thirty hair samples were collected from the male opioid abusers in which the presence of morphine in their urine samples was confirmed by Thin Layer Chromatography [TLC] analyses. The hair samples were washed, cut into small pieces and extracted in a mixture of methanol-triflouroacetic acid [9:1]. The methanolic phase was evaporated to dryness under nitrogen stream and derivitized by addition of N-methyl-N-trimethylsilyl triflouroacetamide [MSTFA] and 1% trimethyl iodosilane [TMIS] with sonication. One micro liter of each derivitized sample was injected into a Gas Chromatograph-Mass Spectrometer [GC/MS] system consisting of a capillary column and finnigan MS with selective ion monitoring [SIM] mode. The selected mass for ions codeine and morphine were 370 and 429, respectively. The limit of detection [LOD] was set at 0.03ng/mg of the hair. By using the above procedure, morphine was detectable in all of the examined samples and this method is capable to detec low levels of morphine in hair for a long period of time following the last intake of the drug