Determination of nonelectroactive cations by capillary electrophoresis with amperometric detection at a graphite electrode modified with a thin film of mixed-valent ruthenium-iron cyanide Original Research Article

A graphite electrode modified with a thin film of mixed-valent ruthenium-iron cyanide was prepared and evaluated as an amperometric sensor for nonelectroactive cations in capillary electrophoresis. This electrode was very stable and showed a selective and sensitive response to Cs+. Based on three times signal-to-noise ratio, a detection limit of 2×10−8 M for Cs+ was obtained under the optimized conditions. The applicability of this method was demonstrated for the analysis of synthetically constituted and real samples.