Heated graphite cylinder electrodes

A new heated graphite cylinder electrode (HGCE) has been successfully fabricated, which arrangement is similar to that of the heated metal (Pt or Au) wire electrode invented by Grundler. The cylinders’ diameters range from ca. 95 to 300 μm obtained by grinding the commercial available pencil graphite. HGCEs demonstrate rapid responses to the heating up and high thermal stability during being continuously heated. Predictions for the temperature rise at the electrode surface based on an empirical model for a natural laminar flow at heated cylinders are in good agreement with the experimental results. The temperature rise at HGCEs was found to be strongly dependent on the square of heating currents, the diameter and the temperature coefficient of the specific resistance of the graphite cylinders, and less dependent on the bulk solution temperature. It is indicated the temperature rise at HGCEs was linearly changed with the reciprocal of the square of the cylinder diameter as the heating currents were given. The evolution from peak-shaped to sigmoid-shaped voltammograms was manifested at HGCEs as the temperature increased from 20 to 95 °C. The compatible between biological substances and graphite electrodes might facilitate studies on the electrochemical behavior of them at HGCEs.