A method of acetate determination by gas phase chromatography using a porous polymer stationary phase is reported that is suitable for use with aqueous and plasma samples. It is linear up to 100 mmol/l and has a coefficient of variation of less than 4% for acetate values of greater than 1 mmol/l. The recovery of acetate from plasma is 92% and sample retention time is 3 minutes. The reference range of plasma acetate in a group of 40 apparently healthy subjects was from less than 0.1 to 0.35 mmol/l. The frequently encountered problem of absorption and ghosting of volatile fatty acids is overcome without the addition of formic acid vapour to the carrier gas.