肉制品中亚硝酸盐的测量不确定度评定

目的 对分光光度法测定肉制品中亚硝酸盐的含量进行测量不确定度评定。方法 根据分光光度法测定亚硝酸盐的检测步骤建立测量不确定度模型，分析影响测定结果的各个分量，最后计算得到合成不确定度。结果 表明标准曲线拟合、试液显色、样品重复测量以及标准曲线制备是测量不确定度的主要来源，在实验过程中需重点关注，提高实验结果的准确度。而样品称量、试样处理液总体积和测定用样液引入的不确定度很小，基本可以忽略。结论 肉制品中亚硝酸盐含量的扩展不确定度为(2.71±0.16) mg/kg(k=2)。

Uncertainty evaluation in measurement of nitrite in meat products

Objective The uncertainty of the determination of nitrite in meat products was evaluated by spectrophotometry. Methods A mathematical model was established according to the procedure of spectrophotometric determination of nitrite. The components that affect the measurement results were analyzed and expanded uncertainty was calculated. Results The results showed that the main sources of uncertainty are the standard curve fitting and color development of test solutions. The repeated measurement of samples and standard working solution preparation were also contributed to the uncertainty. These factors needed to be paid attention to during the determination to improve the accuracy of the results. The uncertainty caused by the sample weighing, the total volume of the sample treatment solution and the measurement sample solution can be ignored. Conclusion The expanded uncertainty of nitrite content in meat products is (2.71±0.16) mg/kg(k=2).