顶空气相色谱法测定血中乙醇含量不确定度分析

摘要

Objective To establish a method for evaluation of uncertainty in determination of ethanol in blood by headspace gas chromatography coupled with flame ionization detector (HS-GC-FID). Methods The concentration of ethanol in blood sample was analyzed by HS-GC-FID. According to the relevant documents for uncertainty evaluation, sources of uncertainty were analyzed, followed by calculation of component factors, combined standard uncertainty (Uc) and expanded uncertainty (Ur). Results The standard uncertainties caused by random effects, balance, purity of the standard, flask, pipet and used standard curves were respective as 7.892×10-3(U1), 1.053×10-4(U2), 1.290×10-3(U3), 1.290×10-4(U4), 2.887×10-3(U5) and 7.069×10-3(U6). On the basis of the data of U1~U6, the combined standard uncertainty (Uc=0.0111) and expanded uncertainty (Ur=0.0222) were obtained. Conclusions The uncertainty in the measurement of ethanol in blood derives mainly from parallel measuring error and importation of standard curves.%目的：对使用顶空气相色谱法测定血液中乙醇含量的方法进行不确定度分析。方法使用顶空气相色谱法测定血液中乙醇的浓度，依据不确定度评定的相关文件，分析该方法不确定度的来源，量化各不确定度分量，评定合成标准不确定度和计算扩展不确定度。结果根据使用顶空气相色谱法测定血液中乙醇含量方法的不确定度包括测试过程随机效应引起的标准不确定度U1（7.892×10-3），天平带来的标准不确定度U2（1.053×10-4），标准品纯度带来的标准不确定度U3（1.290×10-3），容量瓶带来的标准不确定度U4（1.290×10-4），移液枪管带来的标准不确定度U5（2.887×10-3），标准曲线带来的不确定度U6（7.069×10-3），可以得到合成标准不确定度Uc=0.0111，扩展不确定度Ur=0.0222。结论使用顶空气相色谱法测定血液中乙醇含量结果的不确定度主要来源于样品的平行测定误差和标准曲线引入的不确定度。