电化学法测定玉米油酸价的不确定度评定

摘要

According to JJF 1059-1999 ＇Evaluation and Expression of Measurement Uncertainty＇,analyzed the source of uncertainty for electrochemical detection,calculated relative expanded standard uncertainty of corn oil acid value.The uncertainty was caused by many factors,such as electronic weighing scales μ1,glass container μ2,SNR μ3,repeatability of measurement result for standard solution μ4,sample measurement μ5,standard curve μ6 and recovery rate μ7.The results showed that the acid value obtained by electrochemical detection was 0.52mg KOH/g oil and relative value was 0.068mg/g,relative expanded standard uncertainty was 26.2%.%根据JJF1059-1999《测量不确定度评定与表达》方法,分析电化学测定植物油酸价的不确定度来源：电子天平称量引入的不确定度μ1,玻璃量器引入的不确定度μ2,信噪比引入的不确定度μ3,标准工作液重复测定产生的不确定度μ4,样品平行测定产生的不确定度μ5,标准曲线线性拟合产生的不确定度μ6,方法回收率产生的不确定度μ7。计算电化学法检测植物油中游离脂肪酸（以油酸计）酸价的相对扩展标准不确定度,结果表明,电化学法检测玉米油酸价为0.52mgKOH/g油样,相对标准不确定度为0.068mg/g,相对扩展不确定度为26.2%。