Ethyl glucuronide and ethyl sulfate: a review of their roles in forensic toxicology analysis of alcohol postmortem

Abstract

Purpose: This review presents the current methods used for determining ethyl glucuronide (EtG) and ethyl sulfate (EtS) concentrations in postmortem specimens, including sample preparation, analysis and the role of EtG and EtS in the postmortem assessment of the extent of alcohol abuse.

Methods: Papers pertaining to postmortem investigation were collected from scientific databases and reviewed. The papers were published between January 2006 and October 2020.

Results: Most of the analyses involved postmortem blood and urine samples, with a few reports using other bodily specimens and tissues. The method validation was not conducted for all applications. These reports were mostly intended to present data rather than interpret them, and the lack of effort in relating these ethanol biomarkers with the cause of death and/or determination of the time of deaths due to ethanol intoxication might decrease the applicability of these makers after a promising start between 2006 and 2010. Nevertheless, by the beginning of 2020, papers investigating ethanol biomarkers were still increasing. A considerable number of methods used liquid chromatography coupled with mass spectrometry (LC-MS) techniques that require less sample preparation (e.g., protein precipitation extraction, dilution, filtration, and centrifugation). Although solid-phase extraction can be applied, only three applications were reported.

Conclusions: Matrix effects can be a substantial challenge in analytical methods based on LC-MS because they directly affect the ionization of analytes. However, these problems can be avoided due to the high cutoff values used to identify positive results for these ethanol biomarkers, which are often above 0.1-1 mg/L, and using internal standards. Research on using tissue specimens is recommended as most of the reported results on this type of specimen were promising.

Keywords: Blood alcohol concentration; Ethanol; Ethyl glucuronide; Ethyl sulfate; Putrefaction; Urine alcohol concentration.