Microelectrodes are convenient for the investigation of electrochemistry near the limit of quantification in the detection cell, due to their reduced capacitance and their ability to establish a steady state diffusion field. Furthermore, their small dimensions enable the use of higher magnification objectives, which tend to have higher numerical apertures which can collect more light (Figures and), thereby increasing the measured signal at the reporting cell. The expected response when using microelectrodes in the remote reporting system can be investigated by monitoring the oxidation of ferrocenemethanol (FcMeOH) in the detection cell through electrogenerated fluorescence of resorufin in the reporting cell. A sigmoidal voltammogram typical for the oxidation of FcMeOH on a microelectrode is seen in Figure . The capacitive current observed in the voltammetry is caused by the surface roughness of the carbon fibre microelectrode, but is still only around 30 pA in magnitude. Concurrent measurement of the fluorescent signal induced through the closed bipolar electrochemical cell also appears to follow a sigmoidal shape, due to the establishment of steady state conditions at the reporting electrode. However, the fluorescent signal is shifted to more positive potentials compared to the electrochemical signal and its hysteresis is inverted. This indicates a delay between the passage of current through the cell and the onset of fluorescence, possibly due to the chemical reduction by glucose at low overpotentials.