气相色谱法测定大米中毒虫畏的不确定度评估

Uncertainty Evaluating for Determination of Chlorfenvinphos in Rice by GC

建立气相色谱法测定大米中毒虫畏含量的不确定度评定方法。分析测定过程中的不确定度来源,对不确定度的组成进行了评定和量化。根据数学模型计算了样品中毒虫畏的含量,得到合成标准不确定度和扩展不确定度。气相色谱法测定大米中毒虫畏的含量为0.0391 mg/kg,扩展不确定度为0.0034 mg/kg(k=2)。结果表明,不确定度的主要来源是样品溶液中毒虫畏浓度的测定和样品加标回收试验,其次是重复测量和样品定容体积,样品称量引起的不确定度可以忽略。

The method is established to evaluate the uncertainty of gas chromatography(GC)in the determination of chlorfenvinphos in rice.The sources of uncertainty in the process of measurement were analyzed,and the components of uncertainty were evaluated and quantified.The synthetic standard uncertainty and extended uncertainty were calculated according to the mathematical model.The contents of chlorfenvinphos in the sample were 0.0391 mg/kg by GC.The expanded uncertainties were 0.0034 mg/kg(k=2).The determination of chlorfenvinphos concentration in the sample solution and the standard recovery of the sample were the main sources of uncertainty,followed by the repeated determination and the sample volume,and the uncertainty caused by the sample weight can be ignored.