“…The possibilities of using microelectrodes in the form of colloidal particles as heterogeneous catalysts and fluidized bed reactors have also been examined (8)(9)(10). Work has proceeded on a variety of ultramicroelectrode array geometries, including cross sections of epoxy embedded reticulated carbon arrays (1 1, 12) and arrays for liquid chromatography detectors (13). Geometries include those created by photoresist images (14, 'TO whom all correspondence should be addressed 15), carefully placed contiguous carbon fibers (13), sites of inactive oxides on metal substrates (16,17), metal mesh (l8), and platinum particles dispersed in polymer films (19,20).…”