气相色谱法测定水产品中氯氰菊酯残留量的不确定度评定

Evaluation of Uncertainty in Determination of Cypermethrin Residues in Aquatic Products by Gas Chromatography

对气相色谱法测定水产品中氯氰菊酯残留量的测量不确定度进行评定。根据测定方法建立数学模型,分析不确定度的来源,计算合成不确定度及扩展不确定度。结果表明,在95%置信区间,水产品中氯氰菊酯残留量为(4.77±0.44)μg/kg(k=2)。指出,标准溶液配制、标准曲线拟合和前处理过程是不确定度的主要来源。提出,在日常检验过程中,应通过使用精度更高的量器、选择合适的标准曲线浓度范围、规范标准溶液配制过程等措施,提高检测结果的准确度。

A method for evaluating the measurement uncertainty of the determination of cypermethrin residues in aquatic products by gas chromatography was established.A mathematical model was established according to the determination method and the sources of uncertainty were analyzed.The synthetic uncertainty and the extended uncertainty were calculated.Under the 95%confidence interval,the result of cypermethrin residues in aquatic products was(4.77±0.44)μg/kg(k=2).The results point out that standard curve fitting,standard solution preparation and pretreatment processes were the main sources of uncertainty.The results put forward that the accuracy of the results should be improved by using higher calibration levels measuring instruments,selecting a suitable concentration range of the standard curve and standardizing the operation process of the standard solution preparation.