Abstract
Icosapentaenoic acid (IPA) and docosahexaenoic acid (DHA) in five purified fish oils were determined by gas chromatography (GC).
These food components have recently drawn public attention, so the results were expressed as mg/g.
A DB-WAX capillary column was used for the GC, due to its greater separation efficiency. The esterification was compared using both the boron trifluoride-methanol (BF3-methanol) method and the potassium hydroxide-methanol (KOH-methanol) method. The IPA content determined by the KOH-methanol method was found to be approximately 15% higher than by the BF3-methanol method. The DHA content by the KOH-methanol method was also higher by 5%. Determinations of IPA and DHA by both methods showed an intra-laboratory variation of less than 2.5%.
These experimental data showed that IPA and DHA in refined fish oils can be accurately determined by capillary column GC and the esterification using KOH-methanol method.
