The selective detection of dopamine at a polypyrrole film doped with sulfonated β-cyclodextrins

A highly selective dopamine sensor was fabricated by doping polypyrrole with a sulfonated β-cyclodextrin. This composite material enabled the selective sensing of dopamine in the presence of a large excess of ascorbic acid and prevented the regeneration of dopamine through the homogeneous catalytic reaction of the ascorbate anion with the dopamine-o-quinone. A single redox wave, corresponding to the oxidation of dopamine, was observed in dopamine/ascorbate mixtures, giving a truly selective dopamine sensor. The limit of detection was measured as 3.2 × 10−6 M for dopamine.