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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。
OBJECTIVE To analyze the uncertainty of the determination of lead, cadmium, chromium, arsenic and mercury in gold jewelry by ICP-AES, and provide a scientific basis for evaluating the test results. Methods By analyzing the flow of the determination method, a mathematical model was established to determine the source of the uncertainty, and the synthetic uncertainty and the extended uncertainty were calculated from the standard uncertainty of each component. Results The relative expanded uncertainty of determination of lead, cadmium, chromium, arsenic and mercury by ICP-AES was 1.34%, 2.40%, 2.70%, 1.60% and 2.86% respectively. The degree of certainty mainly comes from the working curve fitted by the least square method. Conclusion In practice, several steps, such as standard solution preparation, sample solution preparation and instrument measurement, should be standardized to ensure accurate and reliable measurement results. The evaluation of measurement uncertainty provides a reference for evaluating the accuracy of analytical results and the reliability of the method.