Preliminary investigations on ethyl glucuronide and ethyl sulfate cutoffs for detecting alcohol consumption on the basis of an ingestion experiment and on data from withdrawal treatment.

Ethyl glucuronide (EtG) and ethyl sulfate (EtS) are commonly used alcohol markers for previous alcohol consumption. Nevertheless, the optimum EtG cutoff for urinary abstinence tests is still being discussed, and no cutoff has been recommended for EtS yet. The aim of this study was to verify cutoffs by investigating EtG and EtS concentrations (c(EtG) and c(EtS)) in the urine of healthy persons after drinking small, but realistic amounts of alcohol (one or two glasses of beer or white wine), and to look for the window of detection in strongly alcohol-intoxicated patients who were beginning withdrawal treatment. Very high EtG and EtS concentrations were measured in the first urine samples of patients under withdrawal treatment. However, 24 h later, concentrations decreased considerably, and c (EtG) < 0.5 mg/l and c (EtS) < 0.1 mg/l were determined in 26.7 % (4/13) and 13.3 % (2/13) of the samples, respectively. Concentrations above 0.1 mg/l (EtG) and 0.05 mg/l (EtS) were measured for 23.5 and 20.5 h after consuming 0.1 l of white wine or 0.33 l of beer, and 24 h after the experiment, 75 % (9/12) of the urine samples were tested negative for EtG and EtS using the following cutoffs: EtG 0.5 mg/l and EtS 0.1 mg/l. In half of the samples, concentrations below 0.1 mg/l (EtG) and 0.05 mg/l (EtS) were detected. Urinary cutoffs for EtG of 0.5 mg/l or higher are not suitable for testing abstinence. Even 0.1 mg/l is not effective to detect the intake of small amounts of alcohol in the context of abstinence tests. For EtS, 0.05 mg/l were found to be a potential cutoff to exclude the repeated intake of alcohol. Yet, further research is required to verify this cutoff. For a limited time period, EtG and EtS concentrations within the range of these cutoffs are also detectable after unintentional consumption of alcohol. Participants of abstinence programs have to be informed about the alcohol content of certain foods and beverages whose consumption is in conflict with strict abstinence.

A fully validated high-performance liquid chromatography-tandem mass spectrometry method for the determination of ethyl glucuronide in hair for the proof of strict alcohol abstinence.

Hair analysis has become a powerful tool for the detection of chronic and past drug consumption. For several years, it has been possible to determine even the intake of ethanol in hair samples by detecting the ethanol metabolites ethyl glucuronide or fatty acid ethyl esters. Recently, new requirements were published for the use of EtG as an abstinence test (c(EtG) < 7 pg/mg) as well as for heavy-drinking detection (c(EtG) > 30 pg/mg). In order to perform abstinence tests, a sensitive LC-MS/MS procedure has been developed and fully validated according to the guidelines of forensic toxicology. The nine-point calibration curve showed linearity over the range of concentrations from 2-1,000 pg/mg. Detection and quantification limits were 1 and 4 pg/mg respectively. The intra- and inter-day precision and accuracy were always better than 20%. The validated procedure has successfully been applied to perform abstinence tests and to analyze hair samples from persons in withdrawal treatment. Concentrations between

A SPME-GC/MS procedure for the determination of fatty acid ethyl esters in hair for confirmation of abstinence test results.

Fatty acid ethyl esters (FAEE), direct metabolites of ethanol, are suitable alcohol markers that can be detected in different tissues. The determination of FAEE in hair can help to evaluate social and excessive alcohol consumption. Due to the presence of FAEE in the hair of teetotalers, proving alcohol abstinence seems to be impossible. To verify these results, an solid phase micro extraction-gas chromatography/mass spectrometry procedure for the determination of the four FAEE: ethyl myristate, ethyl palmitate, ethyl oleate and ethyl stearate in hair was validated with special focus on low concentration levels. Besides very high sensitivity (limits of detection between 0.005 and 0.009 ng/mg), good results for linearity, precision and accuracy, recovery and stability were achieved. In addition, 73 hair samples with measured ethyl glucuronide (EtG) concentrations between 4 and 10 pg/mg were analyzed for FAEE. By using the following cut-offs: EtG: 7 pg/mg, FAEE: 0.2 ng/mg a satisfying matching rate of 72.6% was found. This shows that FAEE can be determined to verify borderline EtG concentrations even in the context of abstinence tests. However, the diversified influencing factors on analyte concentrations in hair, which may explain the large deviations between EtG and FAEE results observed in some cases, have to be mentioned when interpret ambiguous results.