Abstract: Synthetic food colourants-tartrazine and ponceau-4R are found to be adsorbed stronglyon a hanging mercury drop electrode and can thus be determined by linear sweep adsorptionvoltammetry.The peaks of derivative waves can be produced at -0.74V and -0.82V respec-tively for tortrazine and ponceau-4R in a buffer solution of disodium hydrogen phosphate,pH-8.8. The determination limit is of 3.0?10^-9mol/L and 2.0?10^-9mol/L respectively.The method has been used to the determination of the colourant in food.

Key words: food colourant, adsorptive voltammetry, tartrazine, ponceau-4R