Bin-Eisa, Fahad Nasser
Diagnostic use of hair analysis for the detection of misuse of amfetamines and cannabinoids.
PhD thesis, University of Glasgow.
Full text available as:
The purpose of this study was to develop a single method to analyse drugs in hair and to apply this to case samples received from The Security Forces Hospital, Saudi Arabia.
First of all, mass fragments and retention times for amfetamines and cannabinoids were identified by GC-MS using derivatization agents, PFPA/ethyl acetate (2:1 v/v) and PFPA / PFPOH (1:0.75 v/v) for amphetamines and cannabinoids, respectively. The results showed good peak shape, good chromatographic resolution and good sensitivity for amfetamine (AF), methamphetamine (MA), 3,4-Methylenedioxyamfetamine (MDA), 3,4-Methylenedioxymethamfetamine (MDMA), 3,4-Methylenedioxyethylamfetamine (MDEA), Δ9-tetrahydrocannabinol (Δ9-THC) and 11-nor-9-carbody- Δ9-tetrahydrocannabinol (Δ9-THC-COOH) compounds.
The comparison of the efficiency of four different pre-treatment methods (enzymatic, alkaline, acid and methanol) to extract AF, MA, MDA, MDMA, MDEA, Δ9THC and Δ9-THC-COOH from hair samples obtained from known amfetamines and cannabinoid abusers was investigated.
The preliminary results demonstrated difficulty with the cannabinoids recovery and the lower concentration of standards were not detected using any of the pre-treatment methods.
As a result of the poor cannabinoids recovery, only the amfetamines were investigated. For the comparison study, only one hair sample positive for amphetamine was available so the pre-treatment comparison study was based on the recovery of AF using the four pre-treatment methods.
The positive hair sample was separated into portions and pre-treatment methods, alkaline (1M NaOH), β-Glucuronidase (helix pomatia), methanol (MeOH) and acid (0.1M HCI) were used on these and compared. The best recovery for amphetamine was obtained using the β-glucuronidase pre-treatment method and this extract was also found to be cleaner than the alkaline and methanol pre-treatments. Β-glucuronidase pre-treatment was selected as the method of choice for the extraction of amphetamine content in hair. The method was validated to include linearity, recovery, intra- and inter-day precision, limit of quantitation (LOQ) and limit of detection (LOD) for all five amphetamine compounds. The method was shown to be reliable and robust for these substances.
The stability of AF in hair was investigated to assess the validity of analysing hair samples for the presence of AF in victims of drowning. Ten amphetamine positive hair samples were submerged in fresh and sea water for different periods of time. The drug concentrations in the samples were monitored over a period of 8 weeks. Hair samples were analysed using the validated method. The results showed a significant decrease of amphetamine in hair with the time submerged in sea water. Fresh water had a much less significant effect over the study period.
The validated method was successfully applied to 16 case samples obtained for living volunteers with a known history of fenethylline (AF precursor) abuse and 6 post-mortem case samples where amfetamines had been detected in the post-mortem blood.
Actions (login required)