石墨炉原子吸收法检验猪肝中铅回收率不确定度的评估

Uncertainty Evaluation of Recovery in the Measurement of Lead in Pigs Liver by GF-AAS

以加标回收实验实际过程及其计算模型为依据,评估石墨炉原子吸收法检验猪肝标准样品中铅含量平均回收率的总不确定度。结果显示,平均回收率的重复性不确定度只占其总不确定度的16%;标准储备液的不确定度只占加标稀释过程总不确定度的38%,是平均回收率总不确定度的0.5%;而加标量观测值的不确定度是平均回收率总不确定度的主要分量,占81%,主要来源于曲线拟合浓度的不确定度。以实际过程及其计算模型为依据的回收率不确定度的评估结果具有更高的严密性和针对性。

Using the actual process of spiking standard recovery experiments and computing model, the total uncertainty of lead measurement using graphite furnace atomic absorption spectrometry pig＇s liver was evaluated. The results shows that the repeatable uncertainty of an average recovery rate composes only 16% of the total uncertainty; standard stock solution composes only 38% of the uncertainty of the spiked dilution process, which is 0.5% of the average recovery rate, whereas the uncertainty of plus scalar observations composes major part of the total uncertainty, accounting for 81%, mainly from the curve fitting the concentration uncertainty. There are higher rigor and relevance if the assessment of recovery rate bases on actual process and computing models.