PREPARATION AND AMPEROMETRIC RESPONSE OF CARBON AND PLATINUM DUAL-CYLINDER MICROELECTRODES

The design and function of an amperometric dual-microelectrode is comm unicated which can operate as a collection sensor. The device consists of two individually addressable microelectrodes of parallel cylindric al geometry. Dual-cylinder microelectrodes have been prepared from mic rometre platinum wire and carbon fibre to extremely good precision usi ng a microscope fabrication technique. The shielding and feedback prop erties of the new microelectrode assembly have been evaluated with res pect to electrode separation For the case of the hexacyanoferrate (iii )/(ii) couple. Carbon fibre (CF) devices with cylinder length of 585 m u m are suitable for the cycling of organic redox couples between narr ow gap electrodes. A discussion follows reporting the selective sensin g of 1,4-dihydroxybenzene at a narrow gap CF device where the chemical and electrochemical effects of ascorbate interferences are Largely fi ltered out to concentrations of 200 mu M.