气相色谱-质谱联用法测定14种食用植物油中的植物甾醇

Determination of Phytosterols of Fourteen Edible Vegetable Oils by Gas Chromatography-Mass Spectrometry

建立了气相色谱-质谱联用测定植物油中4种植物甾醇(豆甾醇、β-谷甾醇、菜籽甾醇和菜油甾醇)的方法。选用超高惰性J&W DB-5MS UI毛细管色谱柱,50%KOH-乙醇为皂化剂,进样量为1μL,分流比20∶1,程序升温,可在32 min内实现上述4种植物甾醇与其他不皂化组分的分离。豆甾醇、β-谷甾醇、菜籽甾醇和菜油甾醇的检出限分别为4.41、6.09、3.10、8.62 mg/L,线性相关系数R≥0.999 2。运用该法对14种25个植物油样品中4种植物甾醇的含量进行了分析,结果表明:玉米油和菜籽油中植物甾醇总量最高,其次是芝麻油;不同种类植物油中植物甾醇的含量和比例各不相同,同一种类不同品牌植物油中各植物甾醇所占的比例基本接近。

A rapid method was established for the simultaneous determination of four phytosterols （ stigmasterol, -sitosterol, brassicasterol and campesterol） in edible vegetable oils by gas chromatography- mass spectrometry （ GC - MS） with the injection of 1 μL in split mode at the ratio of 20： 1. With a ultra inert capillary column ,J＆W DB - 5 MS UI column, and KOH - ethanol as saponify, the four phytosterols and other unsaponifiable matter could be well separated and determined within 32 rain by employing a temperature gradient. Good correlation （ R I〉 0. 999 2 ） and low detection limits were obtained （ the detection limits of stigmasterol, 15 - sitosterol, brassicasterol and campesterol were 4.41,6.09,3.10 and 8.62 mg/L,respectively）. The method was applied to the detection of four phytosterols in 25 samples of 14 kinds of vegetable oils. The results showed that corn oil and rapeseed oil contained the highest phy-tosterols, and the following one was sesame oil. Both the contents and ratios of phytosterols were variable in different kinds of vegetable oils, while the percentage of each phytosterol was almost consistent in different brands of the same oil.