UPLC-MS法测定肉制品中虾过敏原含量的不确定度评定

Evaluation of the uncertainty for the determination of shrimp allergen contents in meat products by UPLC-MS

对采用超高效液相色谱串联质谱(UPLC-MS)法测定肉制品中虾过敏原含量的不确定度进行评定。通过建立数学模型分析UPLC-MS法测定肉制品中虾过敏原含量的方法流程和不确定度的来源,逐一计算不确定度分量并计算合成不确定度,得出扩展不确定度。检测结果的不确定度来源分为样品称量、重复性试验、方法准确度、样品前处理过程和样品溶液测定过程,其中样品溶液测定过程引入的不确定度占比最高,而这部分不确定度的来源主要为标准曲线拟合和对照品称量过程。经计算,方法的合成相对标准不确定度为0.057 9,合成标准不确定度为1.21 mg/kg,取置信度为95%时的扩展因子k=2,计算得到用此方法测定肉制品中虾过敏原含量的相对扩展不确定度为0.116,扩展不确定度为2.42 mg/kg。评定结果中各不确定度分量的占比结果表明:实验过程中应采用调整对照品称样量、合理化标准曲线工作溶液浓度范围的方式以减少方法整体的不确定度。因此,建议在对实际样品进行含量测定时,其报告的检测结果应带有相同单位的测量不确定度值。

The uncertainty for the determination of shrimp allergen contents in meat products by ultra high performance liquid chromatography tandem mass spectrometry(UPLC-MS)was evaluated using a new mathematical model.Specifically,our equations could be applied to calculate each individual uncertainty component,as well as the synthetic uncertainty,and ultimately to generate the extended uncertainty.The uncertainty during the UPLC-MS measurement usually came from the following sources:sample weighing,repeatability test,method accuracy,sample pretreatment process,and sample solution determination process.Among these sources,the sample solution determination process counted the most for the uncertainty,especially from the standard curve fitting and reference sample weighing process.In our case,the relative synthetic standard uncertainty turned out to be 0.0579,with the actual synthetic standard uncertainty as 1.21 mg/kg.Based on the expansion factor k=2 for the confidence at 95%level,the relative expansion uncertainty and actual expansion uncertainty during the measurement of shrimp allergen contents in meat products could be accordingly obtained as 0.116,and 2.42 mg/kg,respectively.According to the contribution of each uncertainty component,the sample weight of the reference substance and the concentration range for the working solution of the standard curve proved to be two key factors for the reduction of overall uncertainty.It is highly recommended that the uncertainty value should be provided whenever the analytical results are reported for the content determination of actual samples.