粮食中磷化物残留测定的不确定度评定

Uncertainty Evaluation of Measurement on Phosphide Residue in Grain

根据JJF 1059.1-2012《测量不确定度评定与表示》技术规范要求,建立了粮食中磷化物残留测定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:一是样品中的磷化物含量,二是试验重复性操作过程,而其他方面的影响很小。其中磷化物含量的不确定度影响又主要来自标准曲线的拟合。因此在实际制备标准曲线时,必须严格规范操作。用该法粮食中磷化物含量是0.040mg/kg,扩展不确定度为1.5×10-3mg/kg。

According to demand of technical standard JJF 1059.1-2012 ‘Evrdurltion and Expression of Uncertainty in Mensurement＇ , mathematical model of measurement uncertainty on phosphide residue in grain was established. Main sources of uncertainty were analyzed and uncertainty effect results of identified source obtained by this method was evaluated. Resnhs showed that phosphide content in samples and experimental repetitive operation process as well affect most, whereas effects of others were small. Uucertainty effect of phosphide content mainly came from the fitting of standard curve. Therefore, standards should be operated strictly in cunstrueting actual standard curve. Phosphide content and expand uncertainty in grain measured by this method were 0.040 mg/kg and 15×10^-3mg/k, respectively.