| Abstract: | GC/EI‐MS‐SIM (gas chromatography / electron ionisation – mass spectrometry with selected ion monitoring) can be easily applied to the determination of fatty acids as methyl esters (FAME). SIM masses should have a high relative abundance and for this reason we suggest m/z 74 and m/z 87 for saturated and monoenoic fatty acids as well as m/z 79 and m/z 81 for FAME with more than one double bond. The relevance and ratio of these fragment ions along with GC retention times enables a good identification of a FAME represented by a peak detected in the chromatograms. Compared to GC with a flame ionisation detector, this simple method provides a higher selectivity and better sensitivity. It also offers the possibilities of using a wide range of internal standards which enables the individual quantification of FAME instead of the determination of their contributions to the fatty acid pattern. |
