微生物法测定鸡枞菌中叶酸含量不确定度评估

为保证测量结果的准确性,对商品试剂盒微生物法测定鸡枞菌中叶酸含量不确定度进行分析。依据CNASCL01-G003-2019要求,并按照JJF 1059.1-2012和GB/Z 22553-2010对实验结果有影响的各个分量进行评估,即对样品测定重复性、样品称量、样品检测过程三个方面引入的不确定度进行分析,并确定了各不确定度分量,得出扩展不确定度。各分量不确定度从大到小分别为样品测定重复性0.0272、移液枪自身容差0.0226、标准品纯度0.002887、温度变化0.0006、容量瓶定容0.0006、样品称量0.00001633;相对合成标准不确定度为0.0356,扩展不确定度为7.7857,测量结果为(109.35±7.7857)μg/100 g。影响微生物法测定鸡枞菌中叶酸含量的最主要不确定度分量为样品测定重复性、移液枪自身容差、标准品纯度引入的不确定度。

Uncertainty Evaluation in Determination of Folic Acid in Termitornyces Eurhizus(Berk.)R.Heim by Microbiological Method

To guarantee the accuracy of the measurement results,this study analyzed the uncertainty in determination of folic acid in Termitornyces eurhizus(Berk.)R.Heim by microbial testing kit.The sources of uncertainty for this method were explored according to CNAS-CL01-G003-2019,GB/Z22553-2010,and JJF 1059.1-2012.That is to analyze the uncertainty introduced from sample determination repeatability,sample weighing and sample testing process,to ascertain standard uncertainty components and expanded uncertainty.The uncertainty components in ascending order included method repeatability at 0.0272,tolerance of pipetting gun at 0.0226,purity of standard product at 0.002887,temperature change at 0.0006,volumetric bottle constant capacity at 0.0006,and sample weighing at 0.00001633;the relative combined standard uncertainty was 0.0356,the expanded uncertainty 7.7857,and the measurement results(109.35±7.7857)μg/100g.The key uncertainty components that influenced the results of determination of folic acid in Termitornyces eurhizus(Berk.)R.Heim were method repeatability,pipette gun tolerance and uncertainty introduced by standard purity.