Gas chromatography determination of fatty acid alkyl esters (methyl and ethyl) in the presence of mono., di- and triglycerides

Determining fatty acid methyl or ethyl esters, in the presence of mono-, di- and tri glycerides, is very important when studying fatty compounds’ methanolysis or ethanolysis, as well as for controlling the quality of petrochemical products. This work presents a useful technique for determining fatty acids methyl or ethyl esters by high temperature gas chromatography in the presence of mono-, di- and triglycerides. Samples were silylated with N, O-bis (trimethylsilyl) tritluoroacetamide (BSTFA) and then passed through a 12 m HT5 column coated with a phenylpolysiloxane-carborane film. Standard methyl and ethyl palmitate, methyl and ethyl oleate, DL-α palmitin, dipalmitin, tripalmitin and triolein solutions were used for calibrating the technique, using tricaprin as internal standard. Retention times and response factors were also determined. The results were employed in following-up palm oil methanolysis and ethanolysis reactions.