SOFT 2004 Meeting Abstracts - Society of Forensic Toxicologists

AS3
DETERMINATION OF ETHYL GLUCURONIDE IN URINE BY GAS CHROMATOGRAPHY­
TANDEM MASS SPECTROMETRY
M Wang*
Department of Biochemistry, Queensland Medical Laboratory, Brisbane, Queensland, Australia
Ethyl glucuronide (EtG) is a metabolite of ethanol, formed by enzymatic conjugation of ethanol with
glucuronic acid, and is regarded as a useful bio-marker of recent alcohol consumption. EtG can be detected
in blood, urine, tissues and hair for an extended time period due to its specific properties of non-volatility,
water-solubility and general stability in comparison to ethanol. A gas chromatography-tandem mass
spectrometry (GC-MSIMS) method was therefore developed for the routine determination of EtG in urine.
Initial extraction involves 3 ml of urine specimen being spiked with 45 ul of EtG-D5 (200 uglml) as
internal standard and was adjusted to pH 6.0. Following extraction using a Strata NH2 SPE column with
methanol and water, the extract was evaporated and derivatized with BSTFA (in 1% TMCS and pyridine)
at 80°C for 30 minutes. After evaporation, the residue was reconstituted in 100 III of acetonitrile. EtG was
assayed on a Varian Saturn 2000 ion trap GC·MS!MS. The standard curve was linear between 1000 and
10,000 Ilglml with curve correlation coefficients exceeding 0.99. The recovery of EtG from solid phase
extraction was approximately 99% at 1000 Ilg/L and 102 % at 8,000 Ilg/L. Measurement of EtG in urine
makes it possible to monitor ethanol consumption using a direct metabolite. This GC-MSIMS method
provides a rapid, simple and specific determination of ethyl glucuronide.
Key words: Ethyl glucuronide, Gas Chromatography -Tandem Mass Spectrometry, Solid Phase Extraction
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