Most permitted synthetic food colouring matters in pH 2 Britton-Robinson buffer give a well defined d.c. voltammetric peak in the range 0.6–1.1 V (versus S.C.E.) at a stationary glassy carbon electrode. The peak currents can be used to determine food colours in the range 2–100 µg ml^–1 either directly or after extraction on polyamide columns. The method is applicable with good precision to single food colours and quality control applications are feasible with some combinations of colouring matters. Serious interference from other constituents has been observed in the determination of amaranth in a blackcurrant health drink.