菜籽油中氯丙醇酯的定量分析

Quantitative analysis of chloropropyl ester in rapeseed oil

针对菜籽油中3-氯-1,2-丙二醇脂肪酸酯(3-MCPD酯)和2-氯-1,3-丙二醇脂肪酸酯(2-MCPD酯)含量的测定建立了一种气相色谱-质谱(GC-MS)测定方法。菜籽油样经甲醇钠碱水解,可将氯丙醇酯水解为游离态的3-MCPD、2-MCPD,水解液经酸中和后,用硅藻土固相萃取柱进行净化,洗脱液经充分脱水后浓缩,七氟丁酰基咪唑(heptafluorobutyrylimidazole,HFBI)衍生,继而采用GC-MS法测定,以同位素内标法进行定量。结果发现,单一氯丙醇酯含量在20~600 ng范围内时,线性较好,检出限为0.03 mg/kg,定量限为0.1 mg/kg;回收率为98.8%~103.0%,相对标准偏差≤3.72%,表明方法准确、可靠,适合菜籽油中氯丙醇酯的定量分析。

A gas chromatography-mass spectrometry(GC-MS)method was established for the determination of 3-Chloro-1,2-Propanediol fatty acid ester(3-MCPD ester)and 2-chloro-1,3-propanediol fatty acid ester(2-mcpd ester)in rapeseed oil.The rapeseed oil sample was hydrolyzed into free 3-MCPD and 2-mcpd by sodium methoxide alkali hydrolysis.After acid neutralization,the hydrolysate was purified by diatomite solid phase extraction column.The eluent was fully dehydrated and concentrated.Heptafluorobutyrylimidazole(HFBI)was derived.Then it was determined by GC-MS and quantified by isotope internal standard method.The results showed that the linearity was good when the content of single chloropropyl ester was in the range of 20~600 ng,the detection limit was 0.03 mg/kg and the quantitative limit was 0.1 mg/kg;The recovery were 98.8%~103.0%,and the relative standard deviation was≤3.72%,which showed that the method was accurate,reliable and suitable for the quantitative analysis of chloropropyl alcohol in rapeseed oil.