Comparison of ethyl glucuronide and fatty acid ethyl ester concentrations in hair of alcoholics, social drinkers and teetotallers

Abstract

In previous investigations hair analysis for ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEE) proved to be suitable for the detection of excessive alcohol consumption. The aim of this study was to compare EtG and FAEE concentrations in hair of alcoholics, social drinkers and teetotallers. Hair samples from 10 alcoholics in withdrawal treatment, 11 fatalities with documented excessive alcohol consumption, four moderate social drinkers who consumed up to 20 g ethanol per day, and three strict teetotallers were analysed. After external degreasing with n-heptane, extraction with a dimethyl sulfoxide/ n-heptane mixture and headspace solid-phase microextraction of the extracts, four fatty acid ethyl esters (FAEEs) (ethyl myristate, ethyl palmitate, ethyl oleate and ethyl stearate) were analysed by gas chromatography–mass spectrometry (GC–MS) with deuterated internal standards. EtG was determined by GC–MS/NCI after ultrasonication of the samples with H 2O, cleanup by SPE with aminopropyl columns and PFP derivatisation. The following concentrations were measured for the four groups: teetotallers EtG < 0.002 ng/mg, FAEE 0.05–0.37 ng/mg, moderate social drinkers EtG < 0.002 ng/mg, FAEE 0.26–0.50 ng/mg, alcoholic patients EtG 0.030–0.415 ng/mg, FAEE 0.65–20.50 ng/mg and the fatalities with alcohol history EtG 0.072–3.380 ng/mg, FAEE 1.30–30.60 ng/mg. The results confirm that by using a cut-off value of the sum of FAEE > 1 ng/mg and/or a positive EtG result in hair, excessive alcohol consumption can be identified using hair analysis. However, no significant correlation between the EtG and FAEE concentrations in the positive cases could be shown. Segmental analysis of some of the specimens did not reveal the same distribution for EtG compared to FAEE in hair, and no chronological accordance compared to the self-reported alcohol consumption could be observed for both parameters. These different results of both methods are discussed in terms of differences between EtG and FAEE in mechanism of formation and incorporation into hair and elimination from hair.