Voltammetric Studies of Anion Transfer Reactions Across a Microhole Array-Water/PVC-NPOE Gel Interface

Voltammetric characterization of hydrophilic anion transfer processes across a 66 microhole array interface between the water and polyvinylchloride-2-nitrophenyloctylether gel layer is demonstrated. Since the transfer of hydrophilic anions including Br-, NO3-, I-, SCN- and ClO4- across the liquid/gel interface usually sets the potential window within a negative potential region, a highly hydrophobic organic electrolyte, tetraoctylammonium tetrakis(pentafluorophenyl)borate, providing a wider potential window was incorporated into the gel phase. The transfer reaction of perchlorate anions across the microhole-water/gel interface was first studied using cyclic voltammetry and differential pulse voltammetry. The full voltammetric response of perchlorate anion transfer was then used as a reference for evaluating the half-wave transfer potentials, the formal transfer potentials and the formal Gibbs transfer energies of more hydrophilic anions such as Br-, NO3-, I- and SCN-. The current response associated with the perchlorate anion transfer across the micro-water/gel interface versus the perchlorate concentration was also demonstrated for sensing applications.