火焰光度计法测定饼干中钠的不确定度评定

Determination of Sodium Uncertainty in Biscuits by Flame Photometer Method

根据GB5009.91-2017《食品安全国家标准食品中钾、钠的测定》及CNAS-GL006:2019《化学分析中不确定度的评估指南》的要求,以火焰光度计法测定饼干中的钠,并对测量结果进行不确定度评定。测得某饼干钠含量为301 mg/100 g,扩展不确定度为13 mg/100 g(95%, k=2)。分析结果表明,影响不确定度的主要因素依次为实验的重复性(贡献度:41.52%)、标准曲线的拟合(贡献度:31.74%)、标准物质的逐级稀释(贡献度:24.07%)、样品称量(贡献度:1.53%)、消解液的定容稀释(贡献度:1.14%)。

As a delicious and convenient snack, biscuits are favored by consumers. In order to more scientifically and rationally express the measurement results of the flame photometric method for determining the sodium content in biscuits, according to GB5009.91-2017 National Standards for Food Safety, Potassium and Sodium in Food "Determination and CNAS-GL006: 2019 Guidelines for the Quantifying Uncertainty in Chemical Analysis, the measurement result uncertainty of measurement result was evaluated. The sodium content of a biscuit was 301 mg/100 g and the extended uncertainty was 13 mg/100 g(95%, k=2). The analysis results showed that the main factors which affect the measurement results were in order: repeatability of the experiment(contribution: 41.52%), fitting of the standard curve(contribution: 31.74%), dilution of the standard substance(contribution: 24.07%), sample weighing(contribution: 1.53%) and constant volume dilution of the digestion solution(contribution: 1.14%). The evaluation method has reference significance for the reasonable labeling of sodium in the nutrition label of pre-packaged food.