Abstract: A nickel phthalocyanine polymer film was deposited on a glassy carbon disc electrode (3 mm diameter) from a solution containing 2 mM Ni(II)-4,9,16,23-tetraaminophthalocyanine monomer and 0.5 M tetraethylammonium perchlorate in DMSO by cycling the potential between -0.2 and +0.9 V vs. SCE at 200 mV/s for the desired number of cycles. The prepared electrode was used at +0.7 V in a FIA system with Ag/AgCl/3 M KCl reference and Au counter electrodes for the determination of the antioxidant t-butylhydroxyanisole (BHA). A carrier solution (3.3 ml/min) containing 0.1 M perchloric acid and 2% methanol was used and the injection volume was 200 µL. The calibration graph was linear for 0.01-10 mg/l BHA, the detection limit was 2.7 µg/l and the RSD (n = 10) for 0.5 mg/l BHA was 1.8%. The electrode responded to sodium bisulfite, t-butylhydroxytoluene, t-butylhydroquinone, ascorbic acid and propyl gallate (PG) and relative errors of higher than 10% were obtained for interferent:BHA concentration ratios of 2:1, 1:2, 1:10, 1:4 and 1:5 respectively. The method was applied to the determination of BHA in biscuits using a standard additions calibration procedure.