二十二碳六烯酸虾青素酯的合成及质谱分析

以二十二碳六烯酸(docosahexaenoic acid,DHA)与虾青素作为反应底物合成DHA虾青素酯,探索出最佳反应条件为:虾青素250 mg、DHA 282 mg、无水丙酮5 m L、4-二甲氨基吡啶(DMAP)100 mg、1-乙基-3(3-二甲基丙胺)碳二亚胺(EDCI)100 mg,充氮、避光、磁力搅拌,25℃反应3 h。液相色谱-质谱联用鉴定结果表明:产物中存在游离虾青素、DHA虾青素单酯、DHA虾青素双酯。经高效液相色谱法测定,采用峰面积归一法进行积分计算出各组分含量,结果表明,最佳反应条件下,产物中DHA虾青素酯峰面积可达95.67%,其中主要为DHA虾青素双酯(77.46%)、部分DHA虾青素单酯(18.21%)和少量游离虾青素(3.24%)。用硅胶层析柱进行梯度洗脱,增加溶剂极性(石油醚-丙酮体积比100∶0~92∶8)依次洗脱出DHA虾青素双酯、DHA虾青素单酯,纯度分别为(98.2±0.5)%和(94.0±0.6)%。

Synthesis and Mass Spectrometry Analysis of Docosahexaenoic Acid Astaxanthin Ester

In this study, docosahexaenoic acid (DHA) and astaxanthin were applied as reaction substrates to synthesize DHA astaxanthin ester The optimal reaction conditions were determined as follows: 250 mg of astaxanthin 282 mg of DHA, 5 mL of anhydrous acetone, 100 mg of 4-dimethylaminopyridine (DMAP) and, 100 mg of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDCI), were reacted in a nitrogen atmosphere under dark conditions with magnetic stirring at 25 ℃ for 3 h. As identified by liquid chromatography-mass spectrometry (LC-MS), the synthesized products were composed of free astaxanthin, DHA astaxanthin monoester and DHA astaxanthin diester. Each of these components was analyzed by HPLC-DAD and quantified by peak area normalization method. The results showed that under optimum conditions, DHA astaxanthin esters accounted for 95.67% of the total products, mainly DHA astaxanthin diester (77.46%), DHA astaxanthin monoester (18.21%) and small amounts of free astaxanthin (3.24%). DHA astaxanthin diesters and DHA astaxanthin monoesters were separated by silica gel column chromatography with increasing solvent polarity from 100:0 to 92:8 (petroleum ether:acetone, V/V). Finally, the purity of the purified DHA astaxanthin diesters and DHA astaxanthin monoesters were (98.2 ± 0.5)% and (94.0 ± 0.6)%, respectively.