植物油中邻苯二甲酸酯含量测定结果的不确定度评定

Uncertainty Evaluation of the Determination of Phthalic Acid Esters in Vegetable Oil

依据GB/T 21911–2008《食品中邻苯二甲酸酯的测定》,采用GPC净化在线浓缩、气相色谱–质谱法测定植物油中的邻苯二甲酸酯类增塑剂。参照JJF1059–1999《测量不确定度的评定与表示》,以测定花生油中邻苯二甲酸二(2-乙基)己酯(DEHP)为例,对整个测量过程中不确定度的来源进行了分析,并对不确定度各个分量进行了评定和合成,取包含因子k=2(约95%置信概率),花生油中DEHP含量为11.8 mg/kg时,扩展不确定度U=1.2 mg/kg。结果表明,随机效应和曲线拟合是影响邻苯二甲酸酯检测过程中的主要因素。

Phthalate esters in vegetable oil were determined by GC-MS through GPC clean up and on-line preconcentration according to GB/T 21911-2008 ＂Determination of Phthalate Esters in Foods＂. According to JJF 1059-1999 ＂Evaluation and Expression of Uncertainty in Measurement＂, bis（2-ethylhexyl）phthalate （DEHP） in peanut oil was taken for instance, the sources of uncertainty in the whole process of measurement were analyzed, each component of uncertainty was estimated and combined. The results showed that the expanded uncertainty U=l.2 mg / kg, as the concentration of DEHP was 11.8 mg/kg with the coverage factor k=-2 （the confidence probability was 95%）. The random effect and curve fitting were the mainly influenced factors in PAEs determining process.