氢化物发生-原子荧光光谱法测定食品添加剂磷酸中铅的测量不确定度评定

Evaluation of the Measurement Uncertainty for the Determination of Lead in Food-Additive Phosphoric Acid by Hydride Generation-Atomic Florescence Spectrometry

按照测量不确定度评定的通用规则,建立了数学模型,对氢化物发生-原子荧光光谱法测定食品添加剂磷酸中铅的测量不确定度进行了评定,分析了方法中的不确定度分量及其来源,计算了各分量的不确定度,最后计算出了检测结果的合成标准不确定度和扩展不确定度。检测结果和不确定度评定结果为(0.190±0.006)mg/kg,k=2。结果表明标准溶液配制是氢化物发生-原子荧光光谱法测定食品添加剂磷酸中铅含量不确定度的主要影响因素。

According to JJF1059-1999 ＂Evaluation and Expression of Uncertainty in Measurement＂,a mathematic model for the determination of lead in food-additive phosphoric acid by hydride generation-atomic florescence spectrometry was established. The calculation formula was deduced. Some data were collected in the procedure of analyzing the sample and the uncertainties of various variables were calculated. The combined uncertainty and expanded uncertainty were finally obtained by synthesizing the uncertainties of various component variables. Results of determination and evaluation of the measurement uncertainty is （0. 190±0. 006）mg/kg,k= 2. The evaluation indicated that the major source of uncertainty was the uncertainty of preparation of standard solutions.