石墨炉原子吸收法测定地表水中铅的不确定度评定

Evaluation of Uncertainty Determination of Lead in Surface Water by Graphite Furnace Atomic Absorption Spectrometry

对石墨炉原子吸收法测定地表水中铅从重复测定样品、工作曲线拟合、铅标准溶液及配制、样品前处理过程四方面进行不确定度分析,发现不确定度最大的部分来源于工作曲线拟合,之后是样品重复测定和样品前处理过程。在工作曲线拟合方面应适当缩小标准曲线范围,使工作曲线覆盖范围尽量与实际样品浓度相匹配,同时严格规范曲线配制的操作过程。在样品的重复测定方面,确保仪器运行的稳定是减小不确定度的关键。

The uncertainty of determination of lead in surface water by GFAAS was analyzed from four aspects:repeated samples,working curve fitting,lead standard solution and preparation and sample pre-treatment process.Among them,the largest part of the uncertainty comes from the working curve fitting,followed by the sample repeated determination and sample pre-treatment.In the fitting of working curve,the range of standard curve should be appropriately reduced,so that the coverage of working curve should match the actual sample concentration as far as possible,and the operation process of curve preparation should be strictly standardized.Ensuring the stability of the instrument operation is the key to reduce the uncertainty in the repetitive determination of samples.