ICP-AES法测定黄金饰品中铅、镉、铬、砷、汞含量的不确定度评估

目的对ICP-AES法测定黄金饰品中铅、镉、铬、砷、汞含量的不确定度进行分析,为评价检验结果提供科学依据。方法通过对测定方法流程进行分析,建立数学模型,确定不确定度的来源,由各分量标准不确定度的计算得到合成不确定度及扩展不确定度。结果用电感耦合等离子体发射光谱（ICP-AES）法测定铅、镉、铬、砷、汞的相对扩展不确定度分别为1.34%、2.40%、2.70%、1.60%、2.86%,此不确定度主要来源于最小二乘法拟合的工作曲线。结论在实际工作中,应规范做好标准溶液的配制、样品溶液的制备、仪器测量等几个步骤,以保证测量结果准确、可靠。测量不确定度的评定为评价分析结果的准确程度和方法的可靠性研究提供了参考。

Evaluation of uncertainty for determination of Pb,Cd,Cr,As and Hg in golden jewelry by ICP-AES

[Objective]To analyze the uncertainty for determination of Pb,Cd,Cr,As and Hg in golden jewelry by ICP-AES,provide a scientific basis for evaluating the test results.[Methods]The sources of uncertainty were identified by analyzing the procedure of method and establishing the mathematical model. The combined uncertainty and expanded uncertainty were derived from standard uncertainty components.[Results]The relative expanded uncertainty of Pb,Cd,Cr,As and Hg in the experiment was1. 34%,2. 40%,2. 70%,1. 60% and 2. 86%,respectively. The uncertainty mainly resulted from the working curve fitting by least square method.[Conclusion]In order to get accurate and reliable results,the procedures such as preparation of standard solution,preparation of sample solution and instrument measurement should be operated according to the standard. The evaluation of uncertainty provides the references for the assessment on accuracy of the results and the reliability research of method.