Electrochemical detection of dopamine using a bare indium–tin oxide electrode and scan rate control

We report sensitive and selective electrochemical detection of dopamine (DA), a neurotransmitter that plays an important role in organisms. The detection of DA is often prevented by the presence of interfering molecules. Therefore, developing a selective and sensitive technology for detection of DA is necessary. The proposed method simply achieves selective and sensitive detection of DA by scan rate control on bare indium–tin oxide (ITO) electrodes. In the case of a low scan rate (50 mV s−1), the anodic peaks of DA and ascorbic acid (AA) appeared at similar potentials (ca. 0.1 V) and both of them showed high anodic peaks. On the other hand, with a high scan rate (5 V s−1), the anodic peak of AA almost disappeared, but the DA peak was still high because of the adsorption of DA to the electrode. The detection limit of this method is 1 nM of DA in the presence of 0.1 mM of AA and 100 nM of DA in human blood serum.