Supercritical fluid fractionation of fish oil esters using incremental pressure programming and a temperature gradient

Incremental pressure programming was demonstrated to be an effective technique for increasing the yield of 90% pure allcis‐5,8,11,14,17‐ethyl eicosapentaenoate (EPA) in the fractionation of urea‐crystallized fish oil ethyl esters using supercritical fluid CO2. The fractionations, which also produced high purity allcis‐4,7,10,13,16,19‐ethyl docosahexaenoate (DHA), were performed using a column temperature gradient. In initial experiments, the maximum temperature of the superimposed gradient was 80°C, and processing pressures ranged from 1900–2200 psi. By reduction of processing pressures, comparable yields of EPA were obtained from fractionations in which the maximum temperatures in the gradient were 70°C and 60°C.