PREPARATION OF FATTY-ACID METHYL-ESTERS FROM BROOK CHARR TISSUES - COMPARISON OF A CLASSICAL AND A DIRECT METHOD

Two methods of preparation (classical and direct) of fatty acid methyl esters (FAME) for gas chromatographic determination were compared for samples of flesh, liver and skin of the brook charr (Salvelinus fonti nalis). The classical method is based on the saponification and methyl ation of a lipid extract from the tissue sample. The direct method is based on the assumption that saponification and methylation of the fat ty acids occurs directly in the flask containing the tissues without p rior lipid extraction and purification steps. The fatty acid profiles obtained by the two methods are comparable for the liver and the skin, but the direct method seems to be more precise for the flesh samples. In addition, the direct method is more rapid for the routine preparat ion of the FAME than the classical method and requires a much lower qu antity of organic solvents, thereby reducing the costs of analysis and disposal of the used solvents.