Alcohol has been widely used in many cultures for centuries. Short-term health risks of alcohol use include intoxication related to the volume of alcohol ingested and the drinking pattern, injuries and violence. Long-term use of alcohol can also lead to serious health risks and alcohol dependence. Moreover, harmful alcohol use and alcohol use disorder may induce social and economic problems.
Recently, some biological state markers have become available to monitor alcohol exposure with high sensitivity and specificity in clinical as well as in forensic practice, occupational medicine, traffic safety and safety at workplace. They are capable of monitoring individuals in treatment for alcohol dependence up to social drinkers in risky situations, including ethyl glucuronide (EtG) and sulfate (EtS) as well as phosphatidylethanol (PEth).
Ethanol is conjugated by UDP-glucuronosyltransferases and sulfotransferases to a low extent by phase II metabolism into EtG and EtS. PEth comprises about 48 phospholipid specimens so far which are formed extrahepatically through phospholipase D, mainly in membranes of the erythrocytes. The PEth homolog 16:0/18:1 is currently the species most commonly determined, and is often simply referred to as PEth.
While PEth is preferably measured in blood, EtG and EtS can be determined from blood and urine, and EtG also from hair specimens. EtG and EtS in urine are short-term markers (< 24="" H="" UP="" TO="" 130="" H,="" DEPENDING="" ON="" DOSE)="" WHEREAS="" PETH="" IN="" BLOOD="" CAN="" BE="" DETECTED="" FOR="" UP="" TO="" 12="" DAYS="" ALREADY="" AFTER="" ONE-TIME="" ALCOHOL="" INGESTION.="">
Even though the pre-analysis especially of PEth is complex, the use of dried matrix spots (DMS) facilitates its determination in routine analysis. Beside PEth, both EtS and EtG have also been determined from DMS. The advantages of DMS relate to ethical, practical, scientific and cost considerations.
EtG and EtS are extracted from DMS using methanol or methanol/acetonitrile mostly followed by liquid chromatography/tandem mass spectrometry (LC-MS/MS). The most used extraction technique for PEth from DMS is protein precipitation with methanol. Separation is based on LC; however, the initially used detection method by light- scattering detection was abandoned in favor of MS/MS.
Beside the most crucial points of DMS-analyses concerning validation, the influence of the hematocrit value, the application mode of the internal standards and the regio-purity of reference materials for PEth analyses, some study results will be presented. The stability of major and minor PEth species determined from DMS will be addressed, as well as the results of studies, investigating the minimum amount of ethanol being necessary to form as much PEth as to exceed the hitherto proposed threshold of 20 ng PEth 16:0/18:1/ml blood separating teetotalism from moderate drinking.
