Determination of ethyl glucuronide in human urine by solid phase extraction-gas chromatography-mass spectrometry

A solid phase extraction (SPE) and gas chromatography (GC) with mass spectrometry (MS) method for determination of ethyl glucuronide (EtG) in human urine was established. One mL urine sample was deproteinated by 100 mu L 3 mol/L hydrochloric acid and cleaned up through a solid phase extraction column. The target analytes were eluted from an NH2-column with 4% ammonia solution and then treated with bis(trimethylsilyl) trifluoroacetamide (BSTFA) + trimethylchlorosilane (TMCS) (99: 1) for derivatization. The derivatized samples were analyzed by GC-MS. Data were acquired in the selected ion monitoring (SIM) mode and the quantitation of EtG was done through internal standard method. Good linearity was obtained at the mass concentration range of 0.1 -3.2 mg/L with a correlation coefficient (r) of 0.9921. The limit of detection (LOD) was 28.4 mu g/L. The range of recoveries was 92. 5% -108. 7%, and the relative standard deviations (RSDs) of intra-day and inter-day were all less than 5%. This method is sensitive, specific, accurate and can be applied to the determination of EtG for medicolegal identification and clinical laboratory.