DISCRIMINATION IN RECOVERY DURING CAPILLARY GLC ANALYSIS OF FISH OIL - THE USE OF A RECOVERY CORRECTION FACTOR (RCF)

A recently proposed capillary GLC method for EPA and DHA determination in fish oils was examined. It was found that whilst the area percentage of each fatty acid showed good reproducibility when an internal standard was used, the mg/g values varied considerably. A linear relationship was observed between mg/g values of EPA and DHA and their relative recovery to C23:0, a commonly used internal standard. Following hydrogenation of the samples it became apparent that losses were likely due to the high susceptibility of polyunsaturates to oxidation. A recovery correction factor was therefore proposed to be incorporated into the calculation of analysis. This may lead to a more accurate estimation of these PUFAs.