电感耦合等离子体质谱碰撞模式内标法测定大米中总砷含量的不确定度评定

Evaluation of Uncertainty for the Determination of Total Arsenic in Rice by ICP-MS with Collision Mode and Internal Standard Method

根据JJF 1059.1-2012和JJF 1135-2005等相关不确定度评估指南中的规定,分析研究了电感耦合等离子体质谱采用碰撞模式结合内标法测定大米中总砷含量的不确定度来源,并评定了各标准不确定度分量。结果表明,该大米样品中总砷含量为0.32 mg/kg,扩展不确定度为0.058 mg/kg,包含因子k为2;该方法测定大米中总砷含量的不确定度主要来源于消解液中砷浓度的定量,尤其是砷标准序列工作曲线的拟合,而其他过程所产生的不确定度较小,可以忽略不计;此外,从大米标准物质实测回收率可以看出,本方法测定大米中总砷的回收率较高,准确度高。

According to the uncertainty evaluation related standards such as JJF 1059.1-2012 and JJF 1135-2005,uncertainty of total arsenic content in rice testing by ICP-MS with collision mode and internal standard method,which has been analyzed and the component of uncertainty has been confirmed. The result shows that the total arsenic content of the rice sample is 0.32 mg/kg,and the extension uncertainty is 0.058 mg/kg,including factor K is 2. The determination of total arsenic content in rice is mainly derived from the quantification of arsenic concentration in digestion solution. In particular,the curve fitting of the arsenic standard sequence plays an important role in computational process of uncertainty,uncertainty of other processes can be neglected. In addition ,the measured recovery of rice standard material can be seen that,this method for determination of total arsenic in rice gets high recovery rate and high accuracy.