Analysis of fatty acid ethyl esters in hair as possible markers of chronically elevated alcohol consumption by headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS)

Fatty acid ethyl esters (FAEE) are products of the nonoxidative ethanol met abolism, which are known to be detectable in blood only about 24 h after th e last alcohol intake. After deposition in hair they should be suitable lon g-term markers of chronically elevated alcohol consumption. Therefore, a me thod for the analysis of ethyl myristate, ethyl palmitate, ethyl oleate and ethyl stearate from hair was developed based on the extraction of the hair sample by a dimethylsulphoxide (DMSO)/n-hexane mixture, separation and eva poration of the n-hexane phase and application of headspace solid-phase mic roextraction (HS-SPME) in combination with gas chromatography-mass spectrom etry (GC-MS) to the extract. For use as internal standards, the correspondi ng D-5-ethyl esters were prepared. The HS-SPME/GC-MS measurements were auto matically performed using a multi-purpose sampler. The detection limits of the FAEE were between 0.01 and 0.04 ng/mg and the reproducibility was betwe en 3.5 and 16%. By application of the method to hair samples of 21 fataliti es with known heavy alcohol abuse 0.045-2.4 ng/mg ethyl myristate, 0.35-13. 5 ng/mg ethyl palmitate, 0.25-7.7 ng/mg ethyl oleate and 0.05-3.85 ng/mg et hyl stearate were measured. For social drinkers (30-60 g ethanol per week), the concentrations were about one order of magnitude smaller. For 10 teeto talers negative results or traces of ethyl palmitate were found. It was sho wn by supplementary investigations in single cases that FAEE are also prese nt in sebum, that there is no strong difference in their concentrations bet ween pubic, chest and scalp hair, and that they are detectable in hair segm ents after a 2 months period of abstinence. From the results follows that t he measurement of FAEE concentrations in hair is a useful way for a retrosp ective detection of alcohol abuse. (C) 2001 Elsevier Science Ireland Ltd. A ll rights reserved.