|SOFT - TIAFT 1998||Scientific Session 5||Thursday October 8, 1998|
|NAIL ANALYSIS FOR DRUGS OF ABUSE|
|Nikolaos P. Lemos, Robert A. Anderson and J. Roy Robertson*|
Department of Forensic Medicine & Science, University of Glasgow, Glasgow G12 8QQ, Scotland, UK
|Fingernail clippings were evaluated as analytical specimens for the detection and quantification of drugs of abuse. Fingernail clippings ( 2.5-25 mg) were obtained from consenting adults attending a drug clinic, together with information concerning the drugs they had used over the previous six months.
Methods for the surface decontamination and extraction of the specimens were evaluated. The nail clippings were decontaminated by sonication in 0.1% sodium, dodecyl sulfate (SDS) followed by sonication in distilled water and methanol. Whereas the SDS and water washes were discarded, the methanolic washes were analysed for the presence of analytes. The nail clippings were then hydrolysed in 1 M NaOH and the hydrolysates were extracted with organic solvents prior to instrumental analysis. Extracts were analysed by RIA, GC-MS or GC equipped with ECD.
Positive RIA results were obtained with specimens from 6 known drug users. The average cannabinoid concentration in fingernail clippings determined by RIA was 1.03 ng/mg. Using GC-MS, the mean D9-tetrahydrocannabinol concentration in fingernail clippings from a further 14 known cannabis users was 1.44 ng/mg. Finally nail clippings from another 6 known drug users were analysed for diazepam and its mean concentration was found to be 25.71 ng/mg. The limits of detection for the RIA method for cannabinoids and the GC-MS method for D9- tetrahydrocannabinol were determined to be better than 0.1 ng/mg. The limit of detection of the GC-ECD method for diazepam was lower than 0.001 ng/mg. The extraction recoveries for our methods were better than 81%.