Analytical perspectives of taurine/graphite oxide electrode coatings

Surface modifications of electrodes aimed at confering them appealing features, such as increased sensitivity and selectivity, still receive a continuously growing attention. Amongst the possible modifiers, are worth mentioning sulphonated species, such as Nafion, poly(p-aminobenzene sulfonic acid), cysteic acid, poly(p-toluene sulfonic acid) and so on [1]. All these species (except Nafion, that is directly casted onto the electrode) are deposited by electrochemical oxidation, either potentiostatically or by cyclic the potential in a wide range. The applications of these sensors are quite widespread [1], spanning from inorganic ions to drugs, pharmaceuticals, herbicides, pollutants, biological fluids, etc. In this contribution, a new type of modified electrode, based on the deposition of a taurine/graphite oxide film onto glassy carbon (GC) electrodes is proposed. The modification of the electrode is achieved by potentiostatic oxidation in a taurine solution using pH 7 phosphate buffer as supporting electrolyte. The modified electrode presents attractive features, such as permselectivity against anions and preconcentration of cations, leading to substancially increased selectivity and sensibility with respect to bare GC electrodes. The research is in progress, especially for evaluating possible applications to the analysis of species of alimentary concern in real samples. In fact, the permselectivity of the modifying layer should be particularly effective in avoid fouling and adsorption phenomena frequently seen in real matrices. [1] E. Desimoni, B. Brunetti, Electroanalysis, 24, 2012, 1481-1500