Highly sensitive and selective voltammetric detection of dopamine with vertically separated interdigitated array electrodes

Abstract

Abstract Highly sensitive (10 −8 mol/dm 3 ) and selective voltammetric detection of dopamine can be carried out with a closely spaced planar interdigitated array (IDA) or vertically separated new IDA electrodes. The sensitivity of dopamine was improved up to 10 −8 mol/dm 3 as a result of high collection efficiency and redox cycling, because twin electrodes with a very small gap make it possible to collect most of the active species oxidized at adjacent electrodes and then to return them to dopamine by reverse reduction before the chemical reaction has terminated. The influence of L ‐ascorbic acid, which interferes with the detection of catecholamines, may be removed by oxidizing it at one electrode, because the oxidized acid converts rapidly to an electrochemically inactive species and is not detected at the other electrode. Dopamine was detected quantitatively in the presence of 10‐fold excess of L ‐ascorbic acid in the same solution.