Intracellular Voltammetry at Ultrasmall Platinum Electrodes

Ultrasmall platinum ring electrodes have been constructed by electrodeposition of platinum Onto carbon ring electrodes. Electrodes thus formed show similar adsorption! desorption peaks for hydrogen and oxygen in 0.50 M H₂SO₄ solution compared to those obtained at conventional-sized electrodes. These electrodes have been used in conjunction with a technique involving linear scan voltammetry and subsequent cleaning pulses. In this technique, the applied potential is ramped anodically from an initial potential to a final potential, then to a large positive potential to clean oxidatively the electrode and a large negative potential for electrode activation. Intracellular measurements of dopamine at platinum ring electrodes have then been studied by integrated pulse linear scan voltammetry. In all experiments, minimal electrode fouling allows repeatable quantitative measurements to be carried out.