Improvements in Vapour-phase Chromatography at Relatively High Temperatures

Abstract

FURTHER experience of the application of the vapour-phase chromatographic method to fatty-acid esters and fatty alcohols¹ has led us to adopt certain improvements which are of general interest. The separation of fatty-acid esters was found to be considerably influenced by the quality of the silicone grease used in the chromatograph column, and, in fact, some batches of silicone grease gave very poor results; treatment of silicone grease with ethyl acetate followed by addition of ethanol and decantation of solvent removed an oily fraction and left a residue of grease which has always, so far, proved very satisfactory. The acetate-washed grease from a ‘poor-quality’ batch was superior even to the best quality unwashed grease, and we have, therefore, used acetate-washed grease in all our subsequent work. We find a mixture comprising 60 per cent ‘Celite 545’ and 40 per cent acetate-washed silicone grease to be satisfactory for applications.