Ethyl glucuronide concentrations in beard hair after a single alcohol dose: evidence for incorporation in hair root.

BACKGROUND: Despite the growing importance of ethyl glucuronide (EtG) in hair for detection of chronic excessive alcohol consumption, the mechanism of incorporation is not yet clear. Deposition from sweat is believed to be the main route. In order to get more information, EtG was determined in daily shaved beard hair after single higher alcohol doses. METHODS: Three volunteers drank within 5.5 h 153, 165 and 200 g ethanol followed by abstinence. Daily shaved beard hair was analysed for EtG using a validated liquid chromatography-tandem mass spectrometry method with a limit of quantification of 2 pg/mg. RESULTS: For all three volunteers, small concentrations of EtG were already detected 9 h after end of drinking. The concentrations increased to maxima of 182, 242 and 74 pg/mg on days 2 to 4 and then gradually decreased to limit of quantification on days 8 to 10. DISCUSSION: The time course of EtG is discussed based on literature data about anatomic dimensions of the hair root, physiology of hair growth, kinetics of EtG formation and elimination in blood, and in comparison to literature results about drugs in beard hair. It follows that for beard hair the predominant portion of EtG is incorporated in the upper part of the hair root between suprabulbar region and isthmus leading to a positive zone of about 3 mm (8-9 days) after a single drinking event. Deposition from sweat which is only possible into the residual hair stubble after shaving and in the infundibulum down to the sebaceous gland mouth was found to be of minor importance but could play a greater role in long hair. CONCLUSION: It is concluded that EtG in hair fulfils the prerequisites for time-resolved interpretation of segmental concentrations and that a single excessive drinking can be well detected in sufficiently short hair segments. However, in the routinely investigated 3-cm proximal scalp hair segment and using the cutoff of 7 pg/mg, a negative result can be expected with high probability because of dilution by negative hair.

11-nor-Delta9-tetrahydrocannabinol-9-carboxylic acid ethyl ester (THC-COOEt): unsuccessful search for a marker of combined cannabis and alcohol consumption.

11-Nor-Delta(9)-tetrahydrocannabinol-9-carboxylic acid ethyl ester (THC-COOEt) can be presumed to be a mixed metabolite formed during combined consumption of cannabinoids and alcohol. In order to examine this hypothesis, THC-COOEt and its deuterated analogue D(3)-THC-COOEt were synthesized as reference substance and internal standard from the corresponding carboxylic acids and diazoethane and methods were developed for the sensitive detection of THC-COOEt in plasma and hair based on gas chromatography-electron impact mass spectrometry after silylation with N-methyl-N-tert-butyldimethylsilyl-trifluoroacetamide and gas chromatography-negative chemical ionization mass spectrometry (GC-NCI-MS) as well as tandem mass spectrometry (GC-NCI-MS-MS) after derivatization with pentafluoropropionyl anhydride. The methods were applied for THC-COOEt determination to plasma samples from 22 drunk driving cases which contained both ethanol (0.30-2.16 mg/g) and THC-COOH (15-252 ng/mL) as well as to 12 hair samples from drug fatalities which were both positive for THC (0.09-2.04 ng/mg) and fatty acid ethyl esters as markers of chronic alcohol abuse (0.70-6.3 ng/mg). In none of these samples THC-COOEt could be found with limits of detection of 0.3 ng/mL in plasma and 2 pg/mg in hair in 11 samples using GC-NCI-MS and 0.2 pg/mg in one sample using GC-NCI-MS. Therefore, the use of this compound as a marker for combined cannabis and alcohol consumption could not be achieved.

Validation of a headspace solid-phase microextraction-GC-MS/MS for the determination of ethyl glucuronide in hair according to forensic guidelines.

The analysis of ethyl glucuronide (EtG) in hair is a powerful tool for chronic alcohol abuse control because of the typical wide detection window of the hair matrix and due to the possibility of segmentation, allowing evaluation of alcohol consumption in different periods. Additionally, EtG in hair is often the only diagnostic parameter of choice for alcohol abuse when other clinical parameters such as ALT, AST, gammaGT and CDT (asialotransferrin and disialotransferrin) are in the normal range and EtG in urine negative. In this paper, we describe the development, optimization and validation of a new method based on hair extraction with water, clean-up by solid phase extraction (SPE), derivatization with heptafluorobutyric anhydride and headspace solid-phase microextraction (HS-SPME) in combination with GC-MS/MS according to forensic guidelines. The assay linearity of EtG was confirmed over the range from 2.8 to 1000 pg/mg hair, with a coefficient of determination (r(2)) above 0.999. The LLOQ was 2.8 pg/mg and the LLOD was 0.6 pg/mg. An error profile calculated according to the "Guide to the Expression of Uncertainty in Measurement" (GUM) at 99% confidence intervals for the range 5-750 pg/mg hair did not exceed 10%. This range corresponds to more than 98% of the positive samples analysed.