Background For almost 30 years, phosphatidylethanol (PEth) has been known as a direct marker of alcohol consumption. This marker stands for consumption in high amounts and for a longer time period, but it has been also detected after 1 high single intake of ethanol (EtOH). The aim of this study was to obtain further information about the formation and elimination of PEth 16:0/18:1 by simulating extensive drinking. Methods After 3 weeks of alcohol abstinence, 11 test persons drank an amount of EtOH leading to an estimated blood ethanol concentration of 1 g/kg on each of 5 successive days. After the drinking episode, they stayed abstinent for 16 days with regular blood sampling. PEth 16:0/18:1 analysis was performed using liquid chromatography‐tandem mass spectrometry (high‐performance liquid chromatography 1100 system and QTrap 2000 triple quadrupole linear ion trap mass spectrometer. Values of blood alcohol were obtained using a standardized method with headspace gas chromatography flame ionization detector. Results Maximum measured concentrations of EtOH were 0.99 to 1.83 g/kg (mean 1.32 g/kg). These values were reached 1 to 3 hours after the start of drinking (mean 1.9 hours). For comparison, 10 of 11 volunteers had detectable PEth 16:0/18:1 values 1 hour after the start of drinking, ranging from 45 to 138 ng/ml PEth 16:0/18:1. Over the following days, concentrations of PEth 16:0/18:1 increased continuously and reached the maximum concentrations of 74 to 237 ng/ml between days 3 and 6. Conclusions This drinking experiment led to measurable PEth concentrations. However, PEth 16:0/18:1 concentrations stayed rather low compared with those of alcohol abusers from previous studies.

␤-D-ethylglucuronide (EtG) is a stable Phase II metabolite of ethanol which can be detected in urine samples several days after elimination of ethanol. It is a useful diagnostic parameter for monitoring abstinence of alcoholics in alcohol withdrawal treatment. For this purpose, determination in urine is mainly performed by LC-MS, LC-MS/MS, or by GC-MS. For the mass spectrometric identification and detection of controlled substances in more sensitive fields such as forensic toxicology, workplace drug testing, doping analysis, and veterinary organic residue control, official guidelines have been released requiring a chromatographic separation and a minimum of two mass spectrometric transitions of the analyte. However alcohol consumption remain suboptimal with regard to sensitivity and specificity. Furthermore, these biomarkers can be influenced by age, gender, and a variety of substances and non-alcohol-associated diseases, and do not fully cover the time axis for alcohol intake. Conjugation of ethanol with activated glucuronic acid in the presence of membrane-bound mitochondrial UDP glucuronyl transferase represents a minor detoxification pathway for ethanol: About 0.02-0.06% (mean) of the dose of ethanol administered is recovered as ␤-D-ethylglucuronide (EtG) in urine in humans [1] and-dose dependent-0.5-1.5% in rabbits [2]. EtG is a non-volatile, water-soluble, stable, direct metabolite of ethanol that can be detected in various body fluids, tissues and hair. EtG (C 8 H 14 O 7 ) has a molecular weight of 222 g/mol, and the melting point (decomposition temperature) is about 150°C. Shortly after the initial consumption of even small amounts of ethanol, EtG is formed. It has been detected in urine up to 80 h after the complete elimination of alcohol from the body and was not detectable in teetotalers with a 0.1 mg/L cut-off [3,4]. EtG is unique in covering this important time span of one to three days after alcohol uptake. In urine, it can be detected longer than ethanol. Therefore, EtG meets the need for a sensitive and specific marker to elucidate alcohol use not detected by

Recent studies show that ethyl glucuronide (EtG) can be decomposed by bacteria; whilst so far no degradation of ethyl sulphate (EtS) has been observed. In the present study, in vitro experiments with bacterial colonies were performed. Bacteria (Escherichia coli, Klebsiella pneumoniae, Clostridium sordellii) were isolated from autopsy material (liver, heart blood, urine, ascites, pericardial fluid, pleural fluid) tested for beta-glucuronidase activity, and three bacterial strains were added to nutrient-deficient medium containing EtG and/or EtS and incubated at 36 +/- 1 degrees C. Samples were taken after various intervals up to 11 days, and EtG and EtS were determined by electrospray ionisation tandem mass spectrometry (LC-ESI-MS/MS). EtG was degraded by E. coli and C. sordellii--complete degradation occurred in the range of 3-4 days--and these bacteria exhibited beta-glucuronidase activity. EtS was not affected within 11 days of incubation.

No abstract

These data suggest that physicians in monitoring programs have a higher rate of unrecognized alcohol use than previously reported. Incorporation of EtG testing into alcohol abstinence monitoring can strengthen these programs.