分光光度法测定火腿肠中亚硝酸盐含量的不确定度评定

目的根据JJF1059.1-2012《测定不确定度的评定与表示》和GB 5009.33-2016《食品安全国家标准食品中亚硝酸盐与硝酸盐的测定》测定火腿肠中亚硝酸盐含量并进行不确定度评定。方法利用分光光度法测定火腿肠中亚硝酸盐含量,并建立相应的数学模型对测定过程中的称量、定容、分取、稀释、测定等引入的不确定度来源及其分量进行系统的分析。结果火腿肠中亚硝酸盐含量为4.31mg/kg,置信概率为95%时,最终得到测量的扩展不确定度为0.138 mg/kg (k=2)。结论火腿肠亚硝酸盐测定过程中最主要的不确定度来源为最小二乘法拟合的曲线,可通过减小标准品称量、定容等操作误差对曲线绘制的影响,进而有效降低最终检测结果的扩展不确定度。

Uncertainty evaluation of determination of nitrite in ham sausage by spectrophotometry

Objective To determine the nitrite content in ham sausage and evaluate the uncertainty according to JJF 1059.1-2012 Evaluation and representation of measurement uncertainty and GB 5009.33-2016 National food safety standards-Determination of nitrite and nitrate in food. Methods The nitrite content in ham sausage was determined by spectrophotometry, and the corresponding mathematical model was established to systematically analyze the source of uncertainty and its components, including weighing, constant volume, fractionation, dilution and so on. Results When the nitrite content in the ham was 4.31 mg/kg and the confidence probability was95%, the expanded uncertainty was 0.138 mg/kg (k=2). Conclusion The standard curve is the main source of the component uncertainties, which can be effectively reduced by reducing the influence of the weighing and constant volume of the standard, Furthermore, the extended uncertainty of the final test result can be effectively reduced, furthermore, the extended uncertainty of the final test result can be effectively reduced.