氢化物原子荧光法测定人发中砷含量的不确定度评定

摘要

目的 评定氢化物原子荧光法测定人发中砷含量的不确定度.方法 以人发标准样品为分析对象,依据化学分析中不确定度的评估指南等指导性文件,分析测定过程中砷含量测定值(C)、样品处理后的总体积(V)、样品称量值(m)以及重复测量( rep)等多个不确定度分量,计算检测结果的合成标准不确定度和扩展不确定度.结果 本文方法测定人发中砷含量的不确定度评定结果为:人发样品中砷的含量为(0.57±0.06)mg/kg,置信概率(p)=95％,自由度(veff)=4.结论 本文方法测量不确定度的主要来源是重复性和校准曲线,测定结果在标准物质给出的含量范围之内.%Objective To evaluate the measurement uncertainty for the determination of arsenic (As) in human hair by hydride generation atomic fluorescence spectrometry ( HG-AFS). Methods With human hair standard material as analyte, each source of uncertainty in the testing procedure was analyzed in detail according to the guidelines of the uncertainty in measurement. After each uncertainty component was evaluated, the combined standard uncertainty and the expanded uncertainty of the result were calculated. Results The concentration of As in human hair was (0. 57 ±0. 06) mg/kg, with a confidence level of 95% and a degree of freedom of 4. Conclusion The result was agree with the certified value of the standard material, and the measurement uncertainty was came primarily from the reproducibility of result and the calibration curve.