Rapid isolation of omega-3 long-chain polyunsaturated fatty acids using monolithic high performance liquid chromatography columns

Eicosapentaenoic and docosahexaenoic acids are important bio-active fatty acids in fish oils. Monolithic HPLC columns both in the polymeric cation exchange (silver-ion) and RP formats were compared with corresponding packed columns for the isolation of these acids from tuna oil ethyl esters. Monolithic columns in both formats enabled rapid (typically 5-10min) separations compared with packed columns (30min). Polymeric monolithic silver-ion disc column rapidly furnished mixtures of eicosapentaenoic and docosahexaenoic esters (90% purity) within 5-10min, but was unable to resolve individual esters. A preparative version of the same column (80mL bed volume) enabled isolation (>88% purity) of 100mg quantities of eicosapentaenoic and docosahexaenoic esters from esterified tuna oil within 6min. Baseline separation of eicosapentaenoic and docosahexaenoic esters was achieved on all RP columns. The results show that there is potential to use polymeric monolithic cation exchange columns for scaled-up preparation of eicosapentaenoic and docosahexaenoic ester concentrates from fish oils.