Montmorillonite chem. modified electrodes (CME) were prepared with certain cationic and anionic species absorbed in the montmorillonite film by both pre-exchange and incorporation methods. The cationic and anionic species absorbed exhibit different voltammetric response when the CME immersed in solns. containing only supporting electrolyte. Only a small fraction of the absorbed species is electrochem. active. X-ray diffraction and spectrophotometry reveal that cationic species can intercalate into the interlamellar spaces to form a clay-org. complex. The electroactivity of the absorbed species was discussed based on the different absorbed sites available in montmorillonite.

Key words: X-RAY DIFFRACTION ANALYSIS, ADSORPTION, CHEMICAL MODIFIED ELECTRODE, MONTMORILLONITE, NEUTRAL RED, ISATIN