QuEChERS-液相色谱/串联质谱法测定青椒中噻虫嗪残留的不确定度分析

Evaluation of uncertainty in determination of thiamethoxam residues in green pepper by QuEChERS-liquid chromatography/tandem mass spectrometry

采用QuEChERS-液相色谱/串联质谱方法测定青椒中噻虫嗪的残留量,并对其测量的结果进行不确定度的评估。结合检测流程建立不确定度的数学模型,分析了影响不确定度评估的主要因素,并通过公式计算其合成不确定度和扩展不确定度。通过评估发现,不确定度主要的影响因素是标准溶液的配制、检测仪器的稳定性和试验前处理过程。当青椒中噻虫嗪的残留量测定结果为140μg/kg时,其扩展不确定度为8μg/kg,结果表示为(140±8)μg/kg,k=2。该方法可为科学评价QuEChERS-液相色谱/串联质谱测定农残的测量结果的准确性提供参考。

QuEChERS liquid chromatography tandem mass spectrometry method was used to determine thiamethoxam residues in green pepper,and the uncertainty of the results was evaluated.Combining with the whole process of the experiment,the mathematical model of uncertainty was established.The main sources of uncertainty affecting the measurement results were analyzed and discussed,and the combined uncertainty and the extended uncertainty were calculated according to the formula.The evaluation revealed that the uncertainty mainly comes from the preparation of the standard solution,the stability of analytical instruments and the pretreatment process.When the determination result of thiamethoxam residue in green pepper is 140μg/kg,the expanded uncertainty is 8μg/kg,and the result is represented as(0.140±0.008)mg/kg,k=2.The method can provide a reference for evaluating the accuracy of the Qu EChERS-liquid chromatography tandem mass spectrometry method in the determination of pesticide residues.