高效液相色谱法测定面粉中乙二胺四乙酸二钠的不确定度评定

Uncertainty evaluation of determination of ethylenediaminetetraacetic acid disodium in flour by high performance liquid chromatography

目的评定高效液相色谱法测定面粉中乙二胺四乙酸二钠(ethylenediaminetetraacetic acid disodium,EDTA-2Na)含量的不确定度。方法采用高效液相色谱法测定面粉中乙二胺四乙酸二钠含量。通过建立数学模型,分析测量不确定度的来源,量化各个测量不确定度分量,合成不确定度。结果面粉中乙二胺四乙酸二钠含量测定的不确定度主要由乙二胺四乙酸二钠标准工作曲线拟合的不确定度所引起,通过分析各分量不确定度发现标准曲线拟合所导致的不确定度较高的主要原因是由于选取的标准溶液浓度范围过宽,样品测量值与标准溶液浓度平均值相差较远。经计算,乙二胺四乙酸二钠含量测定的合成不确定度为2.37%,扩展不确定度为4.74%,测量结果表示为(760.98±36.07)mg/kg,k=2。结论建立的不确定度评定方法适合高效液相色谱法测定面粉中乙二胺四乙酸二钠含量的不确定度分析。

Objective To evaluate the uncertainty of determination of ethylenediaminetetraacetic acid disodium（EDTA-2Na） in flour by high performance liquid chromatography（HPLC）. Methods HPLC was used to determine EDTA-2Na in flour. A calculation formula was established to identify the source of uncertainty. The uncertainty components and the synthetic uncertainties of each measurement were evaluated. Results Uncertainty of fitting standard operating curve of EDTA-2Na mainly caused the uncertainty of determination of the content of EDTA-2Na in flour. Through the analysis of the uncertainty of each component, the main reason of higher uncertainty caused by standard curve fitting was that the concentration range of the standard solution was too wide, and the measured value of the sample was far from the average concentration of the standard solution. The synthetic uncertainty in determination of EDTA-2Na was 2.37% and the expanded uncertainty was 4.74%. The EDTA-2Na content in flour was（760.98±36.07） mg/kg, k=2. Conclusion This study provides a reference for the uncertainty analysis on EDTA-2Na content in flour by HPLC.