电感耦合等离子体原子发射光谱法测定植物油中聚二甲基硅氧烷的不确定度分析

Uncertainty analysis of determination of polydimethylsiloxane in vegetable oil by inductively coupled plasma atomic emission spectrometry

目的评定电感耦合等离子体原子发射光谱法测定植物油中聚二甲基硅氧烷的不确定度。方法按照GB 5009.254-2016对植物油中聚二甲基硅氧烷进行测定,参照JJF 1135-2015、JJF 1059.1-2012等标准建模,分析植物油中聚二甲基硅氧烷测定的不确定度的来源,并对各不确定度分量进行量化和合成。结果当植物油中的检测结果为10.1 mg/kg时,其扩展不确定度为0.111 mg/kg(k=2)。结论影响检测结果的不确定度的主要因素为待测物浓度和回收率,样品称量、试样定容以及重复性测定引入的不确定度可以忽略不计。可以通过多次测量标线点、调整曲线范围、熟练实验步骤、增加平行样、保持仪器的稳定性等来减小测量不确定度。

Objective To evaluate the uncertainty of determination of polydimethylsiloxane in vegetable oil by inductively coupled plasma atomic emission spectrometry.Methods The polydimethylsiloxane in vegetable oil was determined according to GB 5009.254-2016.According to JJF 1135-2015,JJF 1059.1-2012 and other standards,the sources of uncertainty in the determination of polydimethylsiloxane in vegetable oil were analyzed,and the uncertainty components were quantified and synthesized.Results When the detection result in vegetable oil was 10.1 mg/kg,the expanded uncertainty was 0.111 mg/kg(k=2).Conclusion The main factors affecting the uncertainty of the test results are the concentration and recovery of the substance to be measured.The uncertainty introduced by sample weighing,sample volume determination and repeatability determination can be neglected.The measurement uncertainty can be reduced by measuring the marking points for several times,adjusting the curve range,mastering the experimental steps,adding parallel samples,and maintaining the stability of the instrument.