Determination of amphetamine, methamphetamine, MDA and MDMA in human hair by GC-EI-MS after derivatization with perfluorooctanoyl chloride

Abstract

The aim of this study was to develop a quantitative gas chromatography mass spectrometry (GC-MS) method to determine the classical amphetamines and their methylenedioxylated derivatives in human hair. The procedure involved liquid-liquid extraction of hydrolysed hair spiked with deuterated internal standards and direct derivatization with perfluorooctanoyl chloride. After evaporation of the organic phase and dissolution in butylacetate, the derivatized compounds were injected into a GC-MS. Method validation results showed a linear range from 0.25 to 25 ng/mg for the target compounds: amphetamine (AM), methamphetamine (MA), methylenedioxyamphetamine (MDA) and methylenedioxymethamphetamine (MDMA or ecstasy). An intra-day precision of 3-6% RSD and an inter-day precision of 3-17% RSD were observed. Trueness was between 96 % and 106% for the target compounds. The limit of detection ranged from 0.07 to 0.14 ng/mg and of quantification from 0.24 to 0.46 ng/mg, depending on compound. The method was applied on 40 authentic hair samples (segmented or pooled hair), of which 15 cases involved amphetamine and/or ecstasy. The hair concentrations ranged from LOD to 3.2 ng/mg of AM in 7 cases, to 0.4 ng/mg of MDA in 3 cases and to 5.9 ng/mg of MDMA in 13 cases. MA was only detected once at trace level. The method, including the derivatization procedure, is simple and robust with a sensitivity that is satisfactory for measurement of amphetamines and ecstasy in hair from abusers.