火焰原子吸收法测定叶酸片中铁含量的不确定度评估

Evaluation of uncertainty in determination of iron in folic acid tablets by flame atomic absorption spectrometry

目的评定原子吸收法(atomic absorption spectrometry, AAS)测定叶酸片中铁含量测量结果的不确定度。方法样品经过消解后稀释定容,参照GB/T 5009.90-2016采用原子吸收光谱仪进行含量检测。通过对铁含量计算公式的分析,对样品称量、消解液定容体积、标准曲线的拟合、标准溶液的配制、标准物质的纯度、测量的重复性及空白试剂等各个影响因素的不确定度分量进行计算及评估,计算合成的不确定度。结果该叶酸片中的铁含量为41.25 mg/kg,在95%的置信概率下对其进行扩展不确定度为1.24 mg/kg。结论可通过改进标准曲线的配制方式降低不确定度,对叶酸片中铁含量的测定的方法转移提供了参考的检验区间。

Objective To evaluate the uncertainty of the determination of iron content in folic acid tablets by atomic absorption spectrometry(AAS). Methods The sample was diluted with constant volume after digestion, and the content was detected by atomic absorption spectrometer with reference to GB/T 5009.90-2016. Through the analysis of the calculation formula of iron content, the uncertainty components of various influencing factors such as sample weighing, digestion solution constant volume volume, standard curve fitting, preparation of standard solution, purity of standard substance, repeatability of measurement and blank reagent were calculated and evaluated, and then the uncertainty of synthesis was calculated. Results The iron content in the folic acid tablet was 41.25 mg/kg, and the expansion uncertainty was 1.24 mg/kg at a 95% confidence probability. Conclusion The uncertainty can be reduced by improving the preparation of standard curve, which provides a reference interval for the method transfer of determination of iron content in folic acid tablets.