食用植物油中残留溶剂测定的相平衡条件探讨

Study on phases equilibrium conditions for determination of residual solvents in edible vegetable oils by headspace gas chromatography

在采用非极性色谱柱对溶剂组分进行分离的基础上,对食用植物油残留溶剂顶空分析的相平衡条件进行研究。静态顶空分析的灵敏度主要取决于由平衡温度、平衡时间、气液相体积比所决定的气相提取效率,平衡温度显著影响分析的灵敏度,而平衡时间和气液相比例的选择性则不及平衡温度明显,提高平衡温度至溶剂沸点以上可以明显提高检测的灵敏度;通过实验得到优化的相平衡参数为:平衡温度为90℃、平衡时间为30min、取样质量与汽化瓶体积的比值为1.0∶2.5。

By using a non-polar column separation, the equilibrium conditions for the determination of residual solvents in edible vegetable oils by headspace gas chromatography (HSGC) have been developed. The sensitivity of static HS analysis largely depends on the efficiency of gas extraction, which depends on the equilibrium temperature, the volume ratio between the gas and liquid phase and equilibrium time. The equilibrium temperature definitely affects the sensitivity of HS analysis,however, the selection of equilibrium time and phases ratio is not so evident. Increasing the temperature to above the boiling point of the solvents leads to a significant increase in sensitivity of determination. Equilibrium conditions were optimized by means of an experimental design leading to the following conditions: equilibrium temperature 90; the ratio of the oil mass to bottle volume 1.02.5; and equilibrium time 30 min.