微波消解-石墨炉原子吸收光谱法测定保健食品中痕量铅的不确定度评定

Evaluation of Uncertainty in Determination of Lead in Health Food by Microwave Digestion--Graphite Furnace Atomic Absorption Spectrometry

应用测量不确定度评定原理，通过实验对微波消解一石墨炉原子吸收光谱法测定保健食品中痕量铅的不确定度来源及不确定度分量的定量评定进行了研究。测定结果表明，不确定度主要来源为样品溶液中铅浓度、样品测定的重复性及质控物质回收率3方面。当称样量为0．5g时，铅含量为0．12mg／kg，k=2（95％置信度），扩展不确定度为0．008mg／kg，测量结果可表示为（0．12±0．008）mg／kg。

The evaluation of uncertainty in determination of lead in health food by microwave digestion-graphite furnace atomic absorption spectrometry is studied based on a mathematical model and all the factors effected in uncertainty measurement are analyzed. The research results show that the major effective factors of uncertainty in lead measurement are come from lead reference material, repeatability and recovery rate of measurement. When the weight of the sample is 0.5 g, the lead content is 0. 12 mg/kg, k = 2 （ the degree of confidence is 95% ）, the expanded uncertainty is 0. 008 mg/kg, the measurement result can be expressed： （0. 12 ± 0. 008） mg/kg.