ELECTROCHEMICALLY PRETREATED GLASSY-CARBON AS A CHROMATOGRAPHIC SENSOR FOR CATIONIC AND REDOX SPECIES

On oxidative electrochemical pretreatment, the surface of glassy carbon electrodes becomes porous and it adsorbs ions by electrochemical charging. In potentiometric experiments, the potential at a treated carbon electrode increased with increase in the concentration of ionic species, and the electrode was evaluated as an ion detector for ion chromatography. The carbon electrode could detect cations down to 1 x 10(-11) mol (5 x 10(-7) M in 20 mul) when used with an ion-exchange column without a suppressor system and had better sensitivity than conductivity detectors. Further, the redox reactions of the surface sites that were created by pretreatment were reversible, and the electrode potential remained constant after injections of redox analyte.