Florisil固相萃取法联用气相色谱测定油脂中sn-2位脂肪酸

为探寻与气相色谱分析相配套的高效前处理方法,以测定不同物种来源的油脂中sn-2位(β位)脂肪酸组成及含量,考察了Florisil固相萃取柱对经sn-1,3专一性脂肪酶水解后的油脂各产物的分离富集能力,并对萃取条件进行了优化。结果表明,Florisil固相萃取柱能有效地将sn-2单甘脂从油脂水解产物中分离;同时发现Florisil固相萃取可以实现油脂水解产物中甘油三酯、甘油二酯、单甘脂及游离脂肪酸的依次分离。5种不同来源的油脂(植物油、藻油、微生物油脂、鱼油和海豹油脂),水解后经Florisil固相萃取柱萃取,联用气相色谱测定sn-2位脂肪酸组成及含量,结果表明,植物油、藻油和海豹油中sn-2位主要为中长链不饱和脂肪酸(植物油sn-2位中C18∶1,C18∶2和C18∶3约占95%;藻油sn-2位中C16∶1,C18∶1和C18∶2约占50%;海豹油sn-2位中C16∶1,C18∶1和C18∶2约占67%),菌油和鱼油中sn-2位多为长链多不饱和脂肪酸(菌油sn-2位中C20∶4约占37%;鱼油sn-2位中C20∶5,C22∶5和C22∶6约占40%)。

Determination of sn-2 position fatty acid in oils by SPE method with Florisil extraction cartridge coupled with gas chromatography

Florisil extraction cartridge was tested to purify the enzymes-hydrolyzed oil followed by GC analysis. And the results showed that with Florisil extraction cartridge, sn-2 monoglycerol can be separated from the enzymes-hydrolyzed oil efficiently, and the mixture of triacylglycerol, diacylglycerol, monoglycerol and free fatty acid can also be efficiently separated in turn at the optimized extraction conditions. On this basis, 5 different type of oils (plant oil, microbial oil, algal oil, marine animals oil and fish oil) hydrolyzed by sn-1,3 specificity lipase were purified by Florisil extraction cartridge, then sn-2 monoglycerol were collected before methylating. Qualitative and quantitative analysis of sn-2 position fatty acid were performed by GC with a FFAP capillary column. The results showed that sn-2 position fatty acids in plant oil, algal oil and marine animals oil were mainly medium- and long-chain unsaturated fatty acids; sn-2 position fatty acids in microbial oil and fish oil were mainly saturated fatty acids, and in fish oils were mainly long chain polyunsaturated fatty acids.