电感耦合等离子体发射光谱法测定茶叶中铝含量的不确定度分析

目的评定分析电感耦合等离子体发射光谱法(inductivelycoupledplasmaemissionspectrometry,ICP-AES)测定茶叶中铝含量的不确定度。方法检测茶叶样品中铝含量,根据GB/T27025-2008《检测和校准实验室能力的通用要求》和JJF1059.1-2012《测量不确定度评定与表示》中的方法要求对各不确定度分量和合成不确定度进行计算和分析。结果茶叶样品中铝含量为825.2mg/kg,测量结果的合成不确定度为40mg/kg,当k=2置信区间为95%时,其扩展不确定度为80 mg/kg。结论茶叶中铝含量测定中影响不确定度的主要因素是曲线拟合引入的不确定度。

Uncertainty analysis of determination of aluminum in tea by inductively coupled plasma emission spectrometry

Objective To evaluate the uncertainty for the determination of aluminum content in tea by inductively coupled plasma emission spectrometry. Methods The aluminum content in tea samples was measured, and the uncertainty components and composite uncertainty were calculated and analyzed according to the method requirements of GB/T 27025-2008 General requirements for the ability of testing and calibration laboratories and JJF 1059.1-2012 Evaluation and expression of measurement uncertainty. Results The content of aluminum in tea samples was 825.2 mg/kg, and the synthetic uncertainty of measurement results was 40 mg/kg. When the confidence interval of k=2 was 95%, the expanded uncertainty was 80 mg/kg. Conclusion The main factor affecting the uncertainty in the determination of aluminum content in tea is the uncertainty introduced by curve fitting.