Development of epoxy-based voltammetric and ion-selective electrodes

A highly satisfactory method of preparing graphite-loaded epoxy-based coated wire and disc voltammetric electrodes has been developed. The novel technique of multilayer coating and curing of coated surfaces in the atmosphere above a 40% m/m hydrofluoric acid solution presents many advantages: the possibility of obtaining very thin and smooth layers of loaded-epoxy base has been demonstrated to be of great versatility and convenience for the preparation of electrodes in various shapes and sizes. The technique has been extended to the easy and inexpensive fabrication of other types of voltammetric electrodes, namely coated plastic, coated glass and coated fabric electrodes, and to the preparation of ionselective electrodes. Three different types of sulphide ion-selective electrode have been prepared and have been evaluated in standard solutions. The construction adopted here could be a viable alternative to existing methods for the fabrication of inexpensive home-made units. The advantages and versatility of the novel coating and hardening technique in terms of thinness and smoothness of layers, the lack of interference usually presented by common hardeners and catalysts and the resistance shown by the hardened surfaces to common reagents and solventss have been demonstrated. The possibility of polishing and prompt renewal of dirty or damaged surfaces coated by the method presented here has been one of the advantages of the system discussed in the present work. A simple technique of saturating the surfaces of coated plastic electrodes with graphite powder has been introduced. It has been shown to be of great help in the fabrication of coated plastic electrodes and other systems of comparatively low electrical resistance.