^(13)C核磁共振技术测定鱼肝油中ω-3脂肪酸α(1,3)-酰基和β(2)-酰基的位次分布

Position Distribution Study of α(1,3)-acyl and β(2)-acyl of ω-3 Fatty Acids in Cod Liver Oil by ^(13)C-NMR

目的应用^(13)C核磁共振(13C-NMR)光谱测定鱼肝油中ω-3脂肪酸[十八碳四烯酸(C18∶4 n-3,moroctic acid,MA)、二十碳五烯酸(C20∶5 n-3,eicosapentaenoic acid,EPA)、二十二碳六烯酸(C22∶6 n-3,docosahexaenoic acid,DHA)]形成的甘油三脂中α(1,3)-酰基、β(2)-酰基的位次分布。方法用CDCl3溶解样品,利用高分辨核磁共振光谱直接测定。结果鱼肝油中MA、EPA和DHAα(1,3)-酰基、β(2)-酰基在δ171.5~173.5 ppm的化学位移与文献报道基本一致。2批次鱼肝油未发现上述ω-3脂肪酸特征峰,4批次鱼肝油有特征峰检出,但是β(2)-酰基的位次分布不同。按照β(2)-酰基的比例,4批鱼肝油来源于家养鱼类提取的可能性较大。结论应用该13C核磁共振技术可以鉴别鱼肝油的优劣,方法简单、快捷。

OBJECTIVE The position distribution α（1,3）-acyl and β（2）-acyl of ω-3 fatty acids [moroctic acid（C18∶4 n-3, MA）, eicosapentaenoic acid（C20∶5 n-3, EPA） and docosahexaenoic acid（C22∶6 n-3, DHA）] in the form of triacylglycerols in cod liver oil have been examined by 13 C-NMR. METHODS The samples were directly determinated with dissolving in CDCl3 by high resolution 13 C-NMR spectroscopy. RESULTS The 13 C NMR-derived data of the position distribution α（1,3）-acyl and β（2）-acyl for MA, EPA and DHA in δ 171.5-173.5 ppm were consistented with corresponding data reported in the literature. The characteristic peaks of ω-3 fatty acids in two batches cod liver oil were not detected, but that were measured in four batches of cod liver oil with different the position distribution [β（2）-acyl]. According the ratio of the position distribution [β（2）-acyl], the more possibility of extracting from farmed fish in four batches of cod liver oil was found. CONCLUSION The method of 13 C-NMR is simple and quick, which can identify good or bad quality of cod liver oil.