AN ACCURATE MICRODISK SIMULATION-MODEL FOR RECESSED MICRODISK ELECTRODES

This study concentrates on an accurate determination of the chronoampe rometric response for shallow and deep recessed microdiscs. Diffusion to the recessed microdisc is simulated using the finite element method (FEM). The deviation of the chronoamperometric response for a recesse d microelectrode from that for the corresponding inlaid microelectrode can be significant depending on the recess depth. This is noted in te rms of the magnitude of the chronoamperometric response and the shape of the chronoamperometric curves. We find cottrellian current decay fo r deep recess microdiscs at short times ''switching'' to steady-state behaviour at long times. This switch over in behaviour becomes sharper as the depth of the recess increases. The deviation of the recessed m icrodisc response from previously proposed approximate expressions is also discussed, with emphasis on the significant deviations for shallo w recess microdiscs. The simulation model developed here is accurate y ielding transient and steady state values. Approximate analytical expr essions which can be used to calculate the transient and steady state responses for recessed microdisc electrodes are presented. (C) 1998 El sevier Science S.A. All rights reserved.