Determination of the antioxidant octylgallate in food using a polypyrrole electrode modified with nickel phthalocyanine complex. First measurements in a FIA system

A polypyrrole film doped with tetrasulfonated nickel (II) phthalocyanine co mplex, coated by electrochemical polymerisation on a platinum surface, was proved as a good electrochemical detector for the voltammetric analysis of the octylgallate (OG) in food. During the electrode generation, the potenti al of the Pt electrode was controlled at +0.8 V (versus Ag/AgClI/KCl(s) ele ctrode) in aqueous solution. The detection is based on the electrocatalytic properties of the modified conducting polymer. Cyclic voltammograms showed a well-defined oxidation peak for OG. The influence of pH and of methanol/ water ratio in the OG observed response, the cyclic voltammetry and differe nce pulse voltammetry experimental conditions, as well as, the influence of the presence of other phenolic antioxidants were optimised. A detection li mit in the order of micromolar concentration was estimated. The developed a nalytical method was applied to the determination of OG in food, showing it s validity. On the other hand, we have used the polymeric electrode in a FI A system, opening new possibilities for future investigations.