Ethyl glucuronide (EtG) is a minor non-oxidative metabolite of ethanol that is formed from the conjugation of ethanol with glucuronic acid in the liver. Approximately 0.02% of ethanol is converted to EtG and is excreted into urine, breath, blood, hair, and oral fluid. Depending upon the level of alcohol consumption, EtG can be detected in oral fluid for up to a few days following alcohol consumption, while ethanol can only be detected for a few hours. EtG is a preferred biomarker employed by many clinical and forensic toxicology laboratories as an indicator of ethanol consumption, especially in cases pertaining to alcohol dependence, detoxification programs, and even transplant treatment centers.<br/>The current study explores and compares the pre-concentration of EtG from oral fluid onto solid phase microextraction liquid chromatography (SPME LC) tips and thin-film SPME (TF-SPME) mesh, with quantitative analysis of the pre-concentrated samples using either a liquid chromatography – triple quadrupole mass spectrometer (LC-MS/MS) or a direct analysis in real time – time of flight mass spectrometer (DART-TOFMS). Internal standard calibration was employed using matrix-matched oral fluid calibrators and a deuterated analog of EtG. Commercially available oral fluid collection kits were used for collection of EtG-fortified simulated saliva. Results of method optimization experiments designed to maximize SPME recovery and quantitative analysis of EtG will be reported. Figures of merit including limit of detection, limit of quantification, and accuracy and precision of quantification of EtG in oral fluid samples will be presented.

Analysis of ethyl glucuronide in oral fluid using LC-MS/MS and DART-TOFMS with SPME pre-concentration

256th National Meeting (2018)

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