Qualitative analysis of methyl ester by using gas chromatography tandem mass spectrometry detector through its fragmentation and retention indices calculation

Abstract

The Fatty Acid Methyl Ester (FAME) is a part of raw material for biodiesel as alternative fuel to replace fossil fuels. FAMEs which were analysed in this study are the standards of methyl caprate, methyl myristate, methyl palmitate, methyl stearate, methyl oleate, methyl linoleate, and methyl linolenate. Methyl caprate, methyl myristat, methyl palmitate and methyl stearate have an ester functional group and single-chain alkyl; but they have a difference in the number of alkyl chains. Furthermore, methyl stearate, methyl oleate, methyl linoleate and methyl linolenate have the same number of alkyl chains, but they are differences in their double bond in the carbon chain number 9. Analysis of FAME are normally performed by using GC/MS. Analysis of FAME by ion fragmentation according to double bond was discussed in this study. In addition, the identification by using the value of Retention Index (RI) is believed to provide analysis results to be more accurate, because each compound has a different RI value. The RI values obtained from this research are 1324.5; 1724.9; 1934.9; 2137.4; 2113.3; 2107.3; 2125 for methyl caprate, methyl miristat, methyl palmitate, methyl stearate, methyl oleate, methyl linoleate and methyl linolenate, respectively.