无汞盐比色法测定脱皮鱿鱼丝SO_2的不确定度评定

Uncertainty evaluation for determining concentration of Sulfur Dioxide Residue in Peeled Shredded Squid by no mercury salt colorimetry

根据JJF 1059-1999《测量不确定度评定与表示》技术规范要求,建立了无汞盐比色法测定脱皮鱿鱼丝中SO2的测量不确定度的数学模型,分析了不确定度的主要来源,对该方法所得结果的已识别来源的不确定度影响进行评价。结果表明,影响测量结果的主要因素为二氧化硫标准物质、标准曲线拟合引入的不确定度;而样品的称重、样品的定容以及重复性实验引入的不确定度相对较小;用该法测得脱皮鱿鱼丝中SO2为13.35mg/kg,扩展不确定度为0.52mg/kg(95%,k=2);这可为实验室在该检测过程中进一步提高检测数据的可靠性和一致性作参考。

According to evaluation and expression of Uncertainly in Measurement（JJF1059-1999）.A mathematical model was established to assess the uncertainty for determining the concentration of Sulfur Dioxide Residue in Peeled Shredded Squid by no mercury salt colorimetry.Various sources of uncertainty were assessed.The influence of the identified uncertainty of the analytical result was evaluated. The results showed that the key factors of uncertainty were Sulfur dioxide standard substance and the fitting of calibration curve thirdly.Sample weighting, voluming and repeated experiment were subordinate factors of uncertainty.The concentration of lead was 13.35mg/kg and the expanded uncertainty was 0.52mg/kg （95%, k = 2）.It can be used as a reference for the laboratory in the detection process to further improve the reliability of the test data and consistency.