Application of polyphenazine films doped with metal nanoparticles for the measurements of antioxidant capacity

Six glassy carbon electrodes modified with polyphenazine conducting polymers and metallic nanoparticles have been prepared by using electrochemical techniques with the aim of determining antioxidant capacity. The electrodes showed a cathodic peak corresponding to the H2O2 reduction, being adequate for the quantitative studies of this compound. These electrodes can be used to study the interaction between H2O2 and antioxidants. From this interaction it was measured the antioxidant capacity of ascorbic acid. This capacity, in trolox equivalents, was similar for all electrodes studied, and agreed with that previously reported using other contrasted techniques. Platinum nanoparticles modified electrodes are best from the viewpoint of durability but, provided the lower cost of silver salts, silver nanoparticles modified electrodes are also a good selection, though these electrodes must be prepared daily.