枸杞中二氧化硫测定的不确定度评定

Uncertainty Evaluation of Sulfur Dioxide in Wolfberry

依据GB 5009.34-2016《食品安全国家标准食品中二氧化硫的测定》,采用蒸馏法测定枸杞中二氧化硫含量。通过计算和分析测定过程中的不确定度,得到二氧化硫含量为0.051 g/kg时,扩展不确定度为0.0021 g/kg(k=2)。枸杞中二氧化硫含量不确定度的主要来源是标准滴定溶液消耗的体积,其次是重复性测量,以及标准滴定溶液的浓度和样品的称样量。

According to National Food Safety Standard-Determination of Sulfur Dioxide in Foodstuffs(GB 5009.34-2016),the distillation was used to measure the content of sulfur dioxide in wolfberry.The uncertainty during the measuring process was calculated and analyzed.It was obtained that when the content of sulfur dioxide was 0.051 g/kg,the extended uncertainty was 0.0021 g/kg(k=2).The main source of the uncertainty was the volume of standard titration solution,followed by the concentration of standard titration solution and sample weight of specimens.