Renewable surface sol-gel derived carbon ceramic electrode modified with [Ru(NH3)5Cl] (PF6)2 complex :: Application to amperometric detection of chlorate

A novel modified carbon ceramic electrode (CCE) containing [Ru(NH3)(5) Cl](PF6)(2) complex was fabricated by sol-gel technique. The cyclic voltammograms of the modified electrodes show a well defined redox couple due to Ru(III)/Ru(II) system with surface confined characteristics. The stability of the modified CCE modified with ruthenium complex was checked over several days, obtaining reproducible results. Chlorate has been chosen as a model to elucidate the electrocatalytic ability of modified CCE. The modified electrode showed excellent electrocatalytic activity toward chlorate electroreduction in acidic medium. Chlorate was determined amperometrically at the surface of this modified electrode in pH 2 solution. Under the optimized conditions the calibration curve is linear in the concentration range 10 mu M - 5 mM chlorate. The detection limit and sensitivity are 1 mu M and 0.43 nA/mu M respectively. The advantages of the modified CCE is its good stability and reproducibility of surface renewal by simple polishing, excellent catalytic activity and simplicity of preparation. This sensor can be used as an amperometric detector in flow systems. or chromatographic instruments.