Determination of oxamyl by HPLC QI Yongxiu, CAO Mingliang, JIA Baoxiu, WANG Xiaodan (School of Pharmacy, Taishan Medical College , Taian 271000, China) Abstract: Objective: To determine the contents of oxamyl by HPLC. Methods: The liquid chromatography was carried out by the use of Waters symmetry shieldTM RP18 column (150 mm×3.9 mm,5 μm) with the detection wavelength at 234 nm.The flowrate of mobile phase (methanolwater,85:15) was 0.8 ml.min-1, and the internal standard was methmyl oxime. Results: There was a good linear relationship within the range of 2~80 μg.ml-1 (r=0.9998, n=6). The average recovery was 98.82%~100.2%, and RSD in the day was 0.67%. Conclusion: The method is simple, rapid, selective and sensitive.