固相萃取-气相色谱-质谱联用法测定植物油中的胆固醇和4种植物甾醇

Determination of cholesterol and four phytosterols in vegetable oil by solid phase extraction and GC-MS

建立了以固相萃取为前处理方式的气相色谱-质谱联用法(GC-MS)测定植物油中的胆固醇和4种植物甾醇的方法。样品经正己烷溶解,采用Florisil固相萃取柱,以氢氧化四甲基铵为洗脱液进行净化处理,后经HP-5 MS色谱柱(30 m×0.25 mm×0.25μm)分离,GC-MS选择离子扫描(SIM)模式检测,以保留时间和特征离子定性、定量。结果表明:5种甾醇在相应的质量浓度范围内线性关系良好,相关系数均大于0.999,方法检出限为0.2 mg/kg;在空白油样中进行3个水平的添加实验,样品的回收率为84.5%~105.0%,相对标准偏差为1.6%~4.4%。该方法前处理简单、无需皂化、回收率高、精密度好,适用于快速测定植物油样品中的5种甾醇。

A method for determining cholesterol and four phytosterols in vegetable oil was established by GC -MS with solid phase extraction as pretreatment method. The sample was dissolved in n -hexane, and purified by a Florisil solid phase extraction column with tetramethylammonium hydroxide as eluent, then separated on HP- 5 MS capillary chromatographic column （30 m ~ O. 25 mm ~ 0.25 I^m） , and qualitatively and quantitatively analyzed by GC - MS with retention time and characteristic ions under se- lected ion monitoring （SIM） mode. The results indicated that there were good linear relationships in cor- responding mass concentration ranges of the five sterols, the correlation coefficients were all higher than 0. 999, and the detection limit of the method was 0.2 mg/kg. The recoveries and relative standard devia- tions of five sterols were 84.5% - 105.0% and 1.6% -4.4% respectively in three levels addition ex- periment in blank oil. The method had the items of simpleness without saponification, high recovery and precision, suitable for rapid determination of five sterols in vegetable oil.