目的 通过测量不确定度的评定，分析食品接触材料中增塑剂测定过程的关键控制点。方法 采用气相色谱-质谱法测定食品接触材料塑料杯中增塑剂邻苯二甲酸二己酯(DEHP)在50%(体积分数)乙醇模拟溶液、60 ℃水浴温度和1 h迁移时间环境下的迁移量，评估和量化检测过程中的各不确定度因素。结果 在检测过程中，对测量不确定度贡献较大的因素为样品均匀性、检测仪器重复性和迁移时水浴温度的波动，三者的相对标准不确定度分别为9.55×10⁻²，5.67×10⁻²和4.58×10⁻²。结论 分析食品接触材料中增塑剂测定过程关键控制点样品的均匀性及检测仪器的重复性，以3组平行试验为宜，浸泡用电热恒温水浴锅的温度波动需控制在±1.0 ℃。通过严格把控各关键控制点，以确保增塑剂测定结果的准确度和精密度。

The work aims to analyze the critical control points in determination of plasticizer migration from food contact materials though evaluating the uncertainty of measurement. Under the condition of 50% (volume fraction) ethanol of simulated solution, 60 ℃ of the bath temperature and 1 h immersion time, the gas chromatography-mass spectrometry (GC-MS) was employed to determine the migration of the plasticizer dioctyl phthalate (DEHP) in the plastic cup, which belongs to contact materials. Moreover, the uncertainty factors in the detection process were evaluated and quantified. The major factors contributing to the measurement uncertainty in the detection process were the sample uniformity, the repeatability of the detection instrument and the fluctuation of bath temperature during migration. The relative standard uncertainty of the three factors were 9.55×10−2, 5.67×10−2 and 4.58×10−2, respectively. The uniformity of the sample and repeatability of the testing instrument should be carried out in three parallel tests, and temperature fluctuation allowance of the electric thermostatic water bath pot used for detection should be ±1.0 °C. Each critical control points, should be controlled strictly to guarantee the accurate and precise determination result of plasticizer.