气相色谱法测定蔬菜和水果中有机磷及拟除虫菊酯类农药残留不确定度分析

本文旨对气相色谱法测定蔬菜和水果中有机磷及拟除虫菊酯类农药残留量的不确定度进行评定.以NY/T761-2008标准方法为研究对象,选择毒死蜱和甲氰菊酯分别代表方法的第一部分和第二部分,从样品前处理过程、仪器测定、标准溶液配制等7个方面对方法的测量不确定度进行了评估.毒死蜱和甲氰菊酯农药残留的相对扩展不确定度分别为0.9...

Evaluation of the Uncertainty in Determining Organophosphorus and Pyrethroid Pesticides Residue in Vegetables and Fruits by Gas Chromatography

The uncertainty of measuring organophosphorus and pyrethroid pesticides residue in vegetables and fruits by gas chromatography was evaluated in this study. Taking NY/T 761—2008 standard method as the research object, chlorpyrifos and fenpropathrin were selected to represent the first and second parts of the method respectively and the uncertainty of the method was evaluated from seven aspects including the sample pretreatment process, instrument measurement and standard solution preparation etc. The relative expanded uncertainty of chlorpyrifos and fenpropathrin pesticide residue is 0.9% and 1.0% (k=2) respectively, among which the uncertainty component introduced by gas chromatograph peak area, standard solution preparation and standard recovery rate are the main source. In order to reduce the uncertainty of test results, it is necessary to improve the stability of equipment, simplify the preparation process of standard solution and improve the operation ability in practice. Simultaneously, the results of uncertainty should be applied to judge whether the detection data is to be in the critical value of limit.