裂殖壶菌培养物中二十二碳六烯酸含量的测量不确定度评定

摘要

The measurement uncertainty for determination of docosahexenoic acid(DHA)in Schizochytrium sp. culture with gas chromatography by using internal standard method was evaluated.The measurement model of each component in the process of measurement was established according to the experimental principle and method.The sample weight,concentration of internal standard solution,the added volume of internal standard solution,correction factor,the spike recovery and repetitive test were main sources of uncertainty,and the im-pact of these sources were analyzed and identified and the uncertainty component for the measurement uncer-tainty was estimated. The relative standard uncertainty of measurement result of every source was obtained through quantitative analysis. The determination result of DHA content in Schizochytrium sp. culture was 697.3 mg/100 g,the combined standard measurement uncertainty and expanded measurement uncertainty were 9.8 mg/100 g and 19.6 mg/100 g respectively.The evaluation indicated that the effect of sample weight was mini-mal and repetitive test made the most contribution to the combined relative standard measurement uncertainty. And the later was 193 times as to be the former.This evaluation provided a theoretical basis for the quality con-trol of DHA content determination in Schizochytrium sp.culture by GC internal standard method.%采用气相色谱内标法检测裂殖壶菌培养物中二十二碳六烯酸的含量,评定其测量不确定度.根据试验原理和方法建立数学模型,对样品称量、十三烷酸内标配制、标样添加、校正因子、回收率、重复测定等分量因素来源的不确定度进行分析量化后,统计得到合成标准不确定度.样本中二十二碳六烯酸含量检测值697.3 mg/100 g,合成标准不确定度9.8 mg/100 g,扩展不确定度19.6 mg/100 g.结果表明,称量环节的分量不确定度最小,重复测定环节最大,两者相差193倍,为测定裂殖壶菌培养物中二十二碳六烯酸含量的质量控制提供参考.