Abstract: Objective To develop a method for determining ethyl glucuronide（EtG） in blood and urine by liquid chromatograph coupled with tandem mass spectrometer（LC-MS/MS）. Methods After blood and urine de-proteined by acetonitrile, the supernate obtained from a centrifuge was analyzed by LC-MS/MS. Results Determination limit of EtG in both blood and urine was 0.05 μg/mL, with a linear range of 0.10-5.00 μg/mL（r>0.999）. Accuracy in both matrixes was 95%-109%. Inter-and intra-day RSD were less than 12%. The method showed an excellent performance when it was used to analyze authentic blood and urine samples for EtG. Conclusion The method is capable for blood and urine EtG analysis.

Key words: forensic toxicology, blood, urine, LC-MS/MS, ethyl glucuronide