原子吸收分光光度计法测定圆白菜中镉含量的不确定度

Uncertainty evaluation of determination of cadmium in cabbage by atomic absorption spectroscopy

目的评定原子吸收分光光度计法(atomic absorption spectroscopy,AAS)测定圆白菜中的镉含量的不确定度。方法依据JJF 1059.1-2012《测量不确定度评定与表示》,分析整个检测过程中所产生的不确定度来源,计算合成不确定度。结果计算得出圆白菜中镉的含量为0.036 mg/kg,扩展不确定度为0.0046 mg/kg(包含因子k=2)。结论可通过控制标准曲线校准过程和加强对仪器的维护保养等措施来减小原子吸收分光光度法测定圆白菜中镉含量的不确定度,保证实验数据的可靠性,为检测报告提供有力依据。

Objective To evaluate the uncertainty of determination of cadmium in cabbage by atomic absorption spectroscopy （AAS）. Methods According to JJF 1059.1-2012 Evaluation and expression of uncertainty in measurement, the sources of uncertainty in the whole process were analyzed, and the synthetic uncertainty was calculated. Results The content of cadmium in cabbage was 0.036 mg/kg, and the expanded uncertainly was 0.0046 mg/kg （coverage factor, k=2）. Conclusion The control of calibration process of standard curve and the maintenance of analytical instruments and other measures can reduce the uncertainty of determination of cadmium content in cabbage by atomic absorption spectroscopy, so as to ensure the reliability of the experimental data and provide the evidence for the measurement report.