DEVELOPMENT AND VALIDATION OF A GAS CHROMATOGRAPHY METHOD FOR QUANTITATIVE ANALYSIS OF FATTY ACIDS IN VEGETABLE OILS

The major fatty acids present in cosmetics are the unsaturated fatty acids from triglycerides, especially essential fatty acids: linoleic acid (omega -6) and alpha-linolenic acid (omega-3).The purpose of the study was to develop a simple and precise gas chromatography -flame ionization detection method, using an OPTIMA -WAX (macrogol 20000) capillary GC column (30m x 0.32mm x 0.25 mu m) with a run time of 17min, for the analysis of fatty acids composition from vegetable oils and macerated oils. The method was validated for quantifying four major fatty acids: palmitic, stearic, oleic and linoleic acids, as methyl esters. The quantification was performed by internal standardization, using the methyl ester of nonadecanoic acid as internal standard. The esterification reaction was carried out on a magnetic stirrer at a temperature of 80 degrees C and with continuous stirring, in hermetically sealed vials.