目的:建立工作场所空气中米非司酮的超高效液相色谱测定方法。方法:于2018年1至7月，采用玻璃纤维滤膜采集工作场所空气中米非司酮，乙腈/水溶液洗脱，超高效液相色谱-紫外法测定。结果:米非司酮测定方法的检出限为0.005 μg/ml，定量下限为0.015 μg/ml，最低检出浓度为0.14 μg/mn 3（以75 L空气样品）。米非司酮浓度在0.015~40.24 μg/ml线性关系良好，n r=0.999 9。方法的准确度和洗脱效率以回收率计，范围为92.7%~100.0%；平均采样效率为99.6%~100.0%；方法的批内精密度为0.92%~5.41%，批间精密度为0.89%~6.25%；样品在4 ℃条件下可稳定保存3 d。n 结论:米非司酮的超高效液相色谱测定方法操作简便，各项指标达到GBZ/T 210.4-2008《职业卫生标准制定指南　第4部分：工作场所空气中化学物质测定方法》的要求，适用于工作场所空气中米非司酮的检测。“,”Objective:To establish an ultra-high performance liquid chromatography method for the determination of mifepristone in the air of workplaces.Methods:From January to July 2018, glass fiber filter membrane was used to collect mifepristone in the workplace air, eluted with acetonitrile/water solution, and determined by ultra-high performance liquid chromatography-UV method.Results:The detection limit of mifepristone determination method was 0.005 μg/ml, the lower limit of quantification was 0.015 μg/ml, and the lowest detection concentration was 0.14 μg/m n 3 (calculated by collecting 75 L air samples) . The concentration of mifepristone has a good linear relationship between 0.015-40.24 μg/ml, n r=0.9999. The accuracy and elution efficiency of the method were calculated based on the recovery rate, ranging from 92.7% to 100.0%. The average sampling efficiency was 99.6%-100.0%. The intra-assay precision of the method was 0.92% to 5.41%, and the inter-assay precision was 0.89% to 6.25%. The sample could be stored stably for 3 days at 4°C.n Conclusion:The ultra-high performance liquid chromatography method for determination of mifepristone is easy to operate, and its indicators meet the requirements of GBZ/T 201.4-2008 “Guidelines for the Establishment of Occupational Hygiene Standards Part 4: Methods for Determination of Chemical Substances in Workplace Air”, which is suitable for the detection of mifepristone in the air of the workplace.