REDOX-CATALYTIC REDUCTION OF DIOXYGEN BY COBALTOCENE AT A CARBON-PASTE ELECTRODE - APPLICATION TO TRACE ANALYSIS

The redox-catalytic reduction of dioxygen at a carbon paste electrode took place when trace amounts of cobaltocenium salts substituted by el ectron-withdrawing groups were added. A potentiometric technique was s et up, which allowed the detection of cobaltocenium salts down to ca. 1 X 10(-7) M in a non-deaerated phosphate buffer solution (pH 7.4). Th e detection limit of a cobaltocenium-labeled model drug was ca. 2 X 10 (-7) M under conditions which mimic competitive immunoassays.