A comparative study on the optimization of the fatty acids pretreatment parameters using central composite design with response surface methodology

Comparative studies on esterification methods for the quantitative determination of fatty acids (FAs) were accomplished using a rotatable central composite design (RCCD). The effect of the three methylation methods on the isomerization of unsaturated fatty acids in gas chromatography analysis was also evaluated. The experimental design showed that the effect of both temperature and duration time of reaction on the recovery of methylation was significant. After optimization, the method was validated and the results for linearity, precision, and limit of detection (LOD) were presented. Methods were similar on account of the fatty acid methyl esters recovery (%) determined (91.30–96.44%). The acid-catalyzed procedures gave no isomerization of conjugated dienes and no artifacts, but artifacts were observed by using a methyl chloroformate reagent. Therefore, the optimized acid-catalyzed methylation process would be more convenient for polyunsaturated fatty acid analysis, whereas methyl chloroformate reagent would be an alternative for fast analysis.