原子荧光法测定稻谷中总汞含量的不确定度评定

Uncertainty evaluation for determination of total mercury content in paddy rice by atomic fluorescence spectrometery

目的建立微波消解原子荧光法测定稻谷样品中的总汞含量不确定度模型。方法按照CNASGL006:2018的评估方法,建立结果不确定度评估数学模型,量化不确定度分量,计算扩展不确定度。结果经评定,稻谷样品中总汞的测定结果为0.0338 mg/kg时,扩展不确定度为0.020 mg/kg(k=2)。结论影响总汞测定不确定度的主要因素是样品制备过程、重复条件下的标准偏差、标准物质。

Objective To establish a evaluation model of uncertainty for determination of total mercury in paddy rice samples by microwave digestion and atomic fluorescence spectrometer.Methods According to the CNAS-GL006:2018,a mathematical model for uncertainty evaluation was established.The component of uncertainty was quantified,and the expanded uncertainty was calculated.Results The expanded uncertainties of the methods was 0.020 mg/kg(k=2),when the determination results of total mercury were 0.0338 mg/kg.Conclusions The main factors affecting the uncertainty of total mercury determination are sample preparation process,standard deviation under repeated conditions and standard substance.