A stationary phase comprising behenic acid, 20 parts, and phosphoric acid, 4 parts, on Chromosorb W (acid-washed), 100 parts, gives excellent gas—liquid chromatographic separations of C 1—C 6 saturated monocarboxylic acids when wet nitrogen is used as the carrier gas. The tolerance of this column packing for substantial amounts of water vapour in the gas phase has permitted development of a much simplified procedure for the quantitative analysis of volatile fatty acid mixtures isolated as sodium salts. A readily made laboratory chromatograph using a commercial, glass electrode, auto-titrator as the detector, is described.