气相色谱内标法测定消毒剂中乙醇含量的不确定度评定

Evaluation of uncertainty of ethanol content in disinfectant by gas chromatography with internal standard curve method

目的对气相色谱内标标准曲线法检测消毒剂中乙醇含量的测量不确定度进行评定。方法乙醇消毒剂样品进行定值测定后,依据测量不确定度评定的相关指导文件,分析测量过程中可能的不确定度来源,计算测量结果的合成标准不确定度和扩展不确定度。结果气相色谱内标标准曲线法测得乙醇消毒剂含量为(70.7±1.9)%。结论对测量结果不确定度贡献较大的分量是标准工作溶液的制备、标准曲线拟合及样品浓度测定、重复性测定等过程引入的不确定度,而标准储备溶液制备、样品的称量、定容及二次定容等过程引入的不确定度分量则相对较小。

Objective To evaluate measurement uncertainty of ethanol content in disinfectant detected by GC with internal standard curve method. Methods Based on relevant guidance documents of uncertainty evaluation,possible sources of uncertainty in measurement process were analyzed,and combined standard uncertainty and expanded uncertainty of the results were calculated,after ethanol disinfectant samples were valued. Results The ethanol content in disinfectant detected by GC with internal standard curve method was（ 70. 7 ± 1. 9） %. Conclusion The uncertainty components which made greater contribution to the result were mainly from the preperation of the standard working solution,the combination of fitting the working curve,the determination of sample concentration and the measurement of repeatability. While others were relatively smaller,which came from the preperation of the standard stock solution,weighing and making first and secondary constant volume of samples.