A poly(vinyl choloride) graphite composite electrode for flow-injection amperometric determination of antioxidants

A new poly (vinyl choloride) (PVC)-composite electrode is described for the determination of propyl gallate (PG), octyl gallate (OG) and tert-butylhydroxyanisole (BHA) used as antioxidants in processed foods. This electrode has favourable properties with respect to its mechanical resistance, very low cost, simple preparation and easy renewal of the electrode surface. A new method to determine antioxidants is developed in order to demonstrate the applicability of this PVC-graphite electrode as an amperometric detector in a flow-injection system using a wall-jet flow cell. The samples are injected into the carrier stream consisting of a KNO3 solution and 10 or 20% (v/v) methanol, Linear calibration graphs are obtained within the ranges 0.1-30, 0.1-13 and 0.1-35 mg l(-1) for PG, OG and BHA, respectively. The applicability of the method was demonstrated by analysing synthetic samples. Finally, the method was applied to the determination of the antioxidants in sunflower oils and soups. (C) 1999 Elsevier Science B.V. All rights reserved.