Abstract: A portion (5 g) of ground biscuit was extracted by shaking with 3 x 25 mL portions of ethyl acetate. After centrifugation, the combined extracts were concentrated to a small volume and diluted to 50 mL with a reversed micellar system consisting of ethyl acetate/0.1 M dioctyl sulfosuccinate/50 mM phosphate buffer of pH 7.4. A portion (150 µL) was injected into a flow injection system in which the carrier stream of the same micellar system. Amperometric measurements were made with a BAS VC-2 tyrosinase electrode, a Ag/AgCl electrode and a Pt wire electrode as the working, reference and counter electrodes, respectively. Calibration graphs were linear up to 1 mM t-butylhydroxyanisole with a detection limit of 30 µM. Batch experiments were also carried out in which the detection limit was 0.1 mM and the linear range was 0.2-2 mM. Of the common antioxidants usually used in food products, only propyl gallate interfered.