Ultrasensitive analysis of microbial fatty acids using gas chromatography with electron capture detection

Pentafluorobenzyl and pentafluoropropionyl/pentafluorobenzyl esters of bacterial fatty acids were analysed by capillary gas chromatography using both flame ionization and electron capture detection. No differences between the relative peak areas of the various fatty acids were observed as regards the two detectors used except that response of the electron capture dectector to the hydroxy acid derivatives exceeded that to the non-hydroxy acid derivatives by 20%. Use of the described derivatives in combination with electron capture detection yields chromatograms comparable with those obtained by analysis of methyl esters using flame ionization detection but with superior sensitivity.