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

A graphite electrode modified with a thin film of mixed-valent ruthenium-ir on cyanide was prepared and evaluated as an amperometric sensor for nonelec troactive cations in capillary electrophoresis. This electrode was very sta ble and showed a selective and sensitive response to Cs+. Based on three ti mes signal-to-noise ratio, a detection limit of 2 x 10(-8) M for Cs+ was ob tained under the optimized conditions. The applicability of this method was demonstrated for the analysis of synthetically constituted and real sample s. (C) 1999 Elsevier Science B.V. All rights reserved.