Metallized graphite-ethylene/propylene/diene terpolymer composite electrodes as electrocatalytic amperometric detectors in flowing systems

Graphite-ethylene/propylene/diene composite electrodes modified with metal particles have been tested as electrocatalytic sensors using various substa nces with different solubilities in water as analytical probes (potassium f errocyanide, ascorbic acid, pentachlorophenol and terbutylhydroxyanisole). The dispersed metal particles lead to a decrease in the oxidation potential s of these compounds which was more pronounced for the Rh-doped electrodes. Thus, Rh-graphite-ethylene/propylene/diene working electrodes were tested in the flow-injection amperometric determination of the antioxidant tertbut ylhydroxyanisole (BHA)., At a working potential of +0.60 V, calibration gra phs were linear within the range 2.0-100 mu mol L-1 BHA With a limit of det ection of 6 10(-7) mol L-1 BHA which is lower than that obtained with a gla ssy carbon electrode in the same experimental conditions or with a Rh-carbo n paste electrode. Furthermore, the robustness of the new electrode materia l has also been demonstrated by checking out its resistance to fouling and to swelling in flowing conditions, as well as by testing the easy regenerat ion of its surface by polishing, and the reproducibility of the analytical response obtained with different electrodes fabricated in the same manner. The developed method with the Rh-graphite-ethylene/propylene/diene electrod e has been applied ro the determination of BHA in biscuit samples.