A microsensor for hydroquinone and catechol was constructed based on a carbon fiber electrode modified by poly(3,4-ethylenedioxythiophene) by several simple steps. This microsensor exhibited excellent electrochemical activity toward the oxidation of the two diphenol isomers, and satisfying results were obtained.

A new composite film-modified electrode was prepared by the electropolymerisation of poly(3,4-ethylenedioxythiophene) (PEDOT) and superconductive carbon black (SCB) on a gold electrode. The PEDOT-SCB/Au electrode exhibited excellent ability towards the electrocatalytic oxidation of ascorbic acid, in terms of a 480 mV shift of the oxidation potential in the negative direction, and a dramatically enhanced oxidation current. Under the optimum conditions, the amperometric detection of ascorbic acid provided a wide linear detection range from 1.0 × 10 -7 to 8.0 × 10 -4 M, and a detection limit of 5.0 × 10 -8 M (S/N = 2) as well as good reproducibility and stability.