微波消解-冷原子吸收法测定大米中汞的不确定度评定

Evaluation of Uncertainty in Determination of Mercury in Rice by Cold Atomic Absorption Spectrometer

建立对微波消解-冷原子吸收法测定大米中汞含量(GB/T5009.17-2006)的不确定度评定方法,探寻不确定度的主要影响因素。按方法GB/T5009.17-2006,大米样品进行平行检测,建立数学模型,系统分析和量化不确定度各分量。微波消解-冷原子吸收法测定大米中汞的含量,当称样量为1.000g,汞含量为0.039mg/kg,k=2(95%置信度),扩展不确定度为0.009mg/kg,测量结果表示为0.039±0.009mg/kg。测量不确定度的来源主要为样品检测的重复性和回收率两方面引起的不确定度,其次为由校准曲线求C0时产生的不确定度。

The evaluation of uncertainty of determination of mercury in rice by cold atomic absorption spectrometer was studied based on a mathematical model and analysis of all factors effected in the measurement uncertainty.The expanded uncertainty was 0.009mg/kg.The result of a measurement was 0.039±0.009mg/kg（k=2）.The major effective factors of uncertainty of mercury measurement are come from repeatability and recovery rate of measurement.