原子吸收分光光度计测定槟榔中钠的不确定度评定

Evaluation of Uncertainty in Determination of Sodium in Areca Nut by Atomic Absorption Spectrophotometer

为提高测量结果的准确度,依据JJF 1059.1—2012《测量不确定度的评定与表示》,对原子吸收分光光度计测定槟榔中钠含量进行不确定度评定。根据GB/T5009.91—2017《食品国家安全标准食品中钾、钠的测定》测定槟榔中钠含量的测定原理,建立影响槟榔中钠含量的数学模型,从标准曲线、样品称量、样品定容、样品测量重复性及仪器设备等方面分析原子吸收分光光度计测量槟榔中钠含量引入的不确定度来源。计算比较得出标准曲线引入的不确定度对试验结果影响是最大的,达到73%,其中标准曲线引入的不确定度主要来源是标准曲线的拟合。当槟榔中钠含量为531 mg/100 g时,其扩展不确定度为28.46 mg/100 g(k=2)。因此,在试验过程中应该加强操作人员的专业能力,确保试验结果的准确性和可靠性。

In order to improve the accuracy of the measurement results,according to JJF 1059.1—2012“Evaluation and Expression of Measurement Uncertainty”,the uncertainty of the determination of sodium content in betel nut by atomic absorption spectrophotometer was evaluated.According to GB/T 5009.91—2017“National Food Safety Standard for the Determination of Potassium and Sodium in Foods”,the determination principle of sodium content in betel nut was established to establish a mathematical model that affects the sodium content in betel nut.From the standard curve,sample weighing,and sample determination Analysis of the source of uncertainty introduced by the atomic absorption spectrophotometer in the measurement of sodium content in betel nut in terms of volume,sample measurement repeatability and equipment.Calculation and comparison showed that the uncertainty introduced by the standard curve has the greatest impact on the experimental results,reaching 73%.The main source of the uncertainty introduced by the standard curve was the fitting of the standard curve.When the sodium content of betel nut was 531 mg/100 g,the expanded uncertainty was 28.46 mg/100 g(k=2).Therefore,the professional ability of the operators should be strengthened during the experiment to ensure the accuracy and reliability of the experimental results.