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目的以自制硫酸硅胶和10%硝酸银硅胶填料分层装填的复合固相萃取柱为净化手段,建立一种测定食用植物油中饱和烃类矿物油的分析方法。方法样品经正己烷提取,固相萃取柱净化,氮吹浓缩,然后经DB-1石英毛细管色谱柱分离,采用气相色谱-火焰离子化检测器检测,外标法定量。结果考察了填料类型、填料用量、洗脱体积等因素对提取效率的影响。在优化的条件下,饱和烃类矿物油检测的线性范围为5.0~500.0mg/L,相关系数r~2=0.9991,方法检出限为3.0 mg/kg,定量限为10.0 mg/kg。样品在10.0、20.0、50.0 mg/kg 3个水平下的加标回收率为93.2%~103.7%,相对标准偏差为3.97%~5.33%(n=6)。结论该法操作简单、快速、准确度高,检出限能满足对食用植物油中饱和烃类矿物油残留的检测要求,且使用常规分析仪器、分析成本低,值得推广应用。
OBJECTIVE To establish a method for the determination of saturated hydrocarbon mineral oil in edible vegetable oil by means of a composite solid-phase extraction column packed with homemade silica gel and 10% silver nitrate silica gel packing. Methods The sample was extracted with n-hexane, purified by solid-phase extraction (SPE) column and concentrated by nitrogen. The sample was separated on a DB-1 quartz capillary column and detected by gas chromatography-flame ionization detector. The results examined the type of filler, the amount of filler, elution volume and other factors on the extraction efficiency. Under the optimized conditions, the linear range of the detection of saturated hydrocarbon mineral oil is 5.0 ~ 500.0mg / L, the correlation coefficient r ~ 2 = 0.9991, the detection limit of the method is 3.0 mg / kg and the limit of quantification is 10.0 mg / kg. The recoveries of spiked samples were 93.2% ~ 103.7% at three levels of 10.0, 20.0 and 50.0 mg / kg with relative standard deviations of 3.97% ~ 5.33% (n = 6). Conclusion The method is simple, rapid and accurate. The detection limit can meet the detection requirements of saturated hydrocarbon mineral oil residues in edible vegetable oils. And it is worth to popularize and apply the analytical instruments with low cost.