Adsorption of phenosafranin at the water vertical bar 1,2 DCE interface: avoltammetric approach

In the present paper the interfacial behavior of a cationic dye, phenosafra nin (PhS+), is voltammetrically analyzed. A sharp and narrow peak during th e negative sweep was observed. The dependence of this peak on concentration , sweep rate and switch potential was a clear indication of an adsorption-d esorption process similar to those observed on solid electrodes. It was det ermined that the adsorbed species results from the ion pairing between dica rbollylcobaltate (DCC-) and PhS+ at the interface as the process is observe d only when the interface is polarized at the potential transfer of DCC-. T he process fitted with a Frumkin isotherm and indicated a strong attractive interaction (g = - 2.3) between the adsorbed species. This interaction was also analyzed spectrophotometrically. (C) 2000 Elsevier Science S.A. All r ights reserved.