Analytical microelectrode voltammetry with minimal instrumentation

The manual recording of near‐steady‐state diffusion currents at inlaid disk or shrouded hemispherical microelectrodes provides a simple and accurate analytical method for a variety of electroactive species in the micromolar and millimolar concentration ranges. The only instrumentation needed is a battery, a chain of resistors, and a battery‐powered picoammeter. A two‐electrode cell suffices. Ferrocene in an acetonitrile solution can be analyzed at concentrations as low as 2.0 μM, but the detection limits are higher in aqueous solutions. Using a simple microcell, as little as 100 pmol of ferrocene could be detected. This work resembles some of the earliest voltammetric studies, but the use of smaller electrodes provides a firmer theoretical foundation to the experiments.