• ethyl glucuronide;
  • direct phase II metabolite;
  • UDP-glucuronosyl transferases;
  • reverse phase;
  • precursor ion;
  • daughter ion


Many different biomarkers can be used to evaluate ethanol intake. Ethyl glucuronide (EtG) is a direct phase II and minor metabolite of ethanol formed through the UDP-glucuronosyl transferase-catalyzed conjugation of ethanol with glucuronic acid. Its investigation is of interest in both clinical and forensic contexts because of the wide window of detection. A sensitive LC-MS/MS procedure has been developed and fully validated according to the guidelines of forensic toxicology for the analysis of EtG in hair. Sample preparation and chromatographic separation were thoroughly optimized. The analysis was performed in the multiple reaction monitoring mode using the transitions m/z 221 [RIGHTWARDS ARROW] 203 (for the quantification) and 221 [RIGHTWARDS ARROW] 85 or 75 (for the qualification) for EtG, and m/z 226 [RIGHTWARDS ARROW] 208 (for quantification) and 226 [RIGHTWARDS ARROW] 75 or 85 (for qualification) for EtG-D5, used as the internal standard. Analyses were carried out using an Inertsil ODS-3 column (100 × 3 mm i.d., 3 µm particle size) and a mobile phase composed of formic acid and acetonitrile. Various SPE cartridges and solvents were tested in order to obtain the highest recoveries and cleanest extracts. The assay linearity of EtG was confirmed over the range from 20 to 2500 pg mg−1, with a coefficient of determination (R2) above 0.99. The lower limit of quantitation (LLOQ) was 20 pg mg−1 and the limit of detection was 10 pg mg−1. Intra- and inter-day assays were less than 15% except at the LLOQ (20%). The analytical method was applied to 72 post-mortem hair samples. EtG concentration in the hair ranged from 0 to 653 pg mg−1 hair. Copyright © 2012 John Wiley & Sons, Ltd.