Tannic Acid–Iron Assembly Films for Electrochemical Sensing of Dopamine

Tannic acid contains a high density of catechol groups, which enable strong interactions with metal ions for the formation of adhesive assembly films. The metal-polyphenol structure formed by tannic acid with metal ions has the advantages of green environmental protection and strong adhesion. In this work, a tannic acid-iron film modified electrode was prepared by a one-step self-assembly method in which ferric chloride hexahydrate and tannic acid were used as reactants. Ultraviolet-visible absorption spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and infrared spectroscopy were used to characterize the structure and morphology of the tannic acid-iron films. Differential pulse voltammetry was used to evaluate the electrochemical sensing performance of the tannic acid-iron film modified electrode towards dopamine. In the range of 450 μM-4 mM, the response current of the modified electrode has a good linear relationship with the dopamine concentration. An anti-interference test of the modified electrode was performed in an electrolyte containing ascorbic acid and uric acid. The electrode has good anti-interference performance. The successful construction of this sensor provides new insights into the research and design of dopamine electrochemical sensors.