ANALYSIS OF THE TRIGLYCERIDES AND THE FREE AND DERIVATIZED FATTY-ACIDS IN FISH-OIL BY CAPILLARY ELECTROCHROMATOGRAPHY

Capillary ElectroChromatography (CEC) on a fused silica capillary colu mn (40 cm L x 100 mu m i.d,) packed with 3 mu m octadecylsilica (ODS) was evaluated for the analysis of the triglycerides and their fatty ac ids in fish oils, and more especially in the oil of Moroccan Sardinia pilchardus. The very high complexity of the lipids in fish oil is well illustrated by CEC with a nonaqueous mobile phase consisting of aceto nitrile/isopropanol/n-hexane in the ratio 57/38/5 to which 50 mM ammon ium acetate has been added. In order to unravel the complexity, the oi l was hydrolyzed and the free fatty acids (FFAs), the methyl esters (F AMEs), and the phenacyl esters (FAPEs) were analyzed by CEC on the sam e column used for the analysis of the triglycerides. Isocratic elution was achieved with the mobile phase acetonitrile/50 mM MES pH 6 in rat io 9/1. The migration characteristics of FFAs, FAMEs, and FAPEs are co mpared. The analysis of FAPE derivatives has the advantage that quanti fication applying UV detection is possible and moreover that the numbe r of double bonds in the fatty acid chains can be elucidated by measur ing the UV abundance ratio 240/210 nm.