Interfacial behavior of sulforhodamine 101 at the polarized water/1,2-dichloroethane interface studied by spectroelectrochemical techniques.

Department of Applied Chemistry, Faculty of Engineering, Nagasaki University, Bunkyo, Nagasaki, 852-8521, Japan.
Analytical and Bioanalytical Chemistry (Impact Factor: 3.58). 11/2006; 386(3):633-8. DOI: 10.1007/s00216-006-0497-z
Source: PubMed

ABSTRACT The transfer mechanism of an amphoteric rhodamine, sulforhodamine 101 (SR101), across the polarized water/1,2-dichloroethane (DCE) interface was investigated using cyclic voltammetry, differential voltfluorometry and potential-modulated fluorescence (PMF) spectroscopy. The voltammetric response for the ion transfer of SR101 monoanion from water to DCE was observed as the diffusion-controlled transfer process. An unusual voltammetric response was found at 0.15 V more negative than the formal transfer potential of SR101(-) (deltaW(O)phi degrees') in the cyclic voltammogram and voltfluorogram. The frequency dependence of the PMF responses confirmed the presence of the adsorption processes at negative potentials. In addition, a further transient adsorption step was uncovered at deltaW(O)phi degrees'. The interfacial mechanism of SR101 is discussed by comparing the results obtained from each technique.

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