Fabrication and Characterization of Pt and Pt-Ir Ultramicroelectrodes.

摘要

Recent work has detailed the preparation of conical and hemispherical Pt-Ir ultramicroelectrodes using a two-step procedure involving an electrochemical etch and the sealing of the resulting sharp wire tip by translation through molten glass. The ultramicroelectrodes were characterized by scanning electron microscopy (SEM) and electrochemically. In this work, the same experimental procedure is extended to the fabrication of Pt ultramicroelectrodes. A new method is described for the characterization of the tip geometry, the electrochemical response of Pt ultramicroelectrodes to Ru(NH3)62+/3+ in water and to FeCp20/+ and Co(CpCOOCH3)20+ in acetonitrile is reported, and aspects related to ultramicroelectrode reliability are addressed. SEM micrographs of freshly etched Pt and Pt-Ir wires are shown in Fig. 1, and the method for characterizing the tip geometry is outlined in Fig.2. Based on this method, freshly etched Pt and Pt-Ir wires have hemispherical radii at their apex of respectively 0.36 and 0.57 microns (95% confidence limits).