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.