Analysis of Double Bond Position in Unsaturated Fatty Acid Methyl Esters by SMCI Method

Introduction

The compounds called fatty acids are measured in wideranging areas from foods to the biological samples. Analysis using the gas chromatograph (GC) is a suitable measurement technique, as GC has a high separation capability in the chromatogram. In this technique, the fatty acids are first derivatized by methyl esterification to produce inactivated fatty acid methyl esters (FAME) with ample volatility. However, because localization of the double bond position in unsaturated FAMEs is difficult, even when using mass spectrometry is used, research on this issue was limited. To overcome this difficulty, an analysis technique based on chemical ionization utilizing acetonitrile was developed (1), and expanded the possibilities of double bond localization. Solvent mediated chemical ionization (SMCI) is a soft ionization method using an organic solvent, and use of the new Shimadzu SMCI unit makes it possible to introduce acetonitrile, which is necessary in this double bond localization technique, into the analytical instrument. This article introduces the results of an analysis of unsaturated FAMEs by the SMCI method. For details of the analytical method and real sample analysis, refer to Shimadzu Technical Reports C146-0396 and C146-0397.

May 11, 2020 GMT