气相色谱法测定蔬菜中16种有机磷农药残留量的测量不确定度评定

目的:评定气相色谱法测定蔬菜中有机磷农药残留量的测量不确定度,为客观分析蔬菜中多组分农药残留检测结果的可靠性提供参考。方法:以NY/T 761-2008第一部分方法二的标准方法为研究对象,分析有机磷农药残留量测定的全过程,从标准溶液、样品制备、重复性、标准曲线拟合和回收率等五个方面对检测方法的测量不确定度进行了评定,确认不确定度的来源和大小,合成标准不确定度,计算扩展不确定度并报出结果。结果:蔬菜中16种有机磷农药的含量范围为0.100~0.339 mg/kg,扩展不确定度范围在0.016~0.052 mg/kg之间(P=95%,k=2)。结论:气相色谱法测定蔬菜中有机磷农药残留量的测量不确定度主要来源为标准曲线拟合,其次为回收率,可通过选择合适的标准溶液浓度制作标准曲线、优化前处理方法、质控样品等措施减少不确定度,保证检测结果的准确、可靠。

Evaluation of Measurement Uncertainty in the Determination of 16 Kinds of Organophosphorus Pesticide Residues in Vegetables by Gas Chromatography

Objective:To evaluate the measurement uncertainty of organophosphorus pesticide residues in vegetables by gas chromatography and provide a reference for objective analysis of the reliability of multi-component pesticide residue detection results in vegetables.Methods:The whole process of determination of organophosphorus pesticide residues was analyzed based on the standard method of the second method in the first part of NY/T 761-2008.The uncertainty of the detection method was evaluated from five aspects:standard solution,sample preparation,repeatability,standard curve fitting and recovery rate.The source and value of uncertainty were confirmed. The synthetic standard uncertainty was synthesized. The extended uncertainty was calculated and the results were reported.Results:The content of 16 organophosphorus pesticides in vegetables were 0.100 mg/kg to 0.339 mg/kg,and the extended uncertainty was 0.016 mg/kg to 0.052 mg/kg(P=95%,k=2).Conclusion:The measurement uncertainty of organophosphorus pesticide residues in vegetables by gas chromatography was mainly derived from standard curve fitting,followed by recovery rate.By choosing appropriate concentration of standard solution to make standard curve,optimizing pretreatment method and quality control sample,the uncertainty can be reduced,and the accuracy and reliability of test results can be guaranteed.