食用植物油中残留溶剂的高温顶空气相色谱分离与测定

Isolation and Determination of Residual Solvents in Edible Vegetable Oils by High Temperature Headspace Gas Chromatography

对食用油中C5～C8烃类残留溶剂的高温顶空气相色谱分离与测定进行方法学考察。样品在90℃进行顶空平衡以提高样品残留溶剂组分在顶空气相中的分配,并采用25%角鲨烷填充色谱柱对溶剂组分进行分离和定量分析。结果表明,30min内的高温平衡对组分测定无干扰;不同组分保留时间的RSD均不超过0.2%、峰面积的RSD也均小于5%,方法的回收率为99.2%,最低定量限均低于0.5mg/kg;顶空分析的相平衡条件、色谱分离模式不同导致本方法与国家标准方法的测定结果间存在显著差异;国家标准方法中六号溶剂标准溶液的配制对定量分析结果影响显著。本方法可用于监控油脂加工中溶剂残留的变化以及精炼油的质量检测。

By combining HTHS sampling with GC separation, a method for the confirmation and quantification of residual hydrocarbons having a number of carbon atoms ranging from 5 to 8 in edible oil samples has been developed and tested. The sample was heated at 90℃ to achieve equilibrium and increase the transfer of residual hydrocarbons into the headspace, and then, a 25% squalane packed-column was used to perform the isolation and determination. The results showed that no interferences were noted within 0.5h equilibrium. The repeatability of the analytes （expressed as a relative standard deviation, RSD） for simulant sample is： 〈 0.2 % for retention time and 〈 5 % for peak area, the total recovery 99.2%, and LOQ （limit of quantitative） less than 0.5mg/kg. The equilibrium model, chromatographic separation model and quantitative method lead to a significant difference between the new method and the current GB method. The making-up of standard solution of No.6 solvents from different resources definitely affects the quantification of analytes by GB method. The achieved method may better be used to follow variations of residual solvents during vegetable oil manufacturing process and to detect the quality of refined oil.