Improved Gas Chromatography of Unesterified Fatty Acids

Abstract

IT has been demonstrated by Böttcher et al.¹ and by Hunter et al.² that unesterified fatty acids can be separated, by gas chromatography, by the use of ‘liquid’ phases of the polyester type. Metcalfe³ has pointed out the necessity to have a highly acidic ‘liquid’ phase in order to suppress the association of the carboxyl group of the fatty acids, and has shown that the separation of C₄–C₂₂ fatty acids is very much improved by the incorporation of phosphoric acid in the polyester ‘liquid’ phase. Using a column packing of ‘Celite 545’ previously coated with 25 per cent of diethylene glycol adipate polyester and 2 per cent of phosphoric acid, mixtures of fatty acids were separated at temperatures of 220–235° C., yielding well-defined symmetrical peaks and separating saturated and unsaturated acids from each other.