Thin Hematite Film Based Flavin Microsensor

Abstract

We developed a new microelectrode with a tip made of a hematite film for the detection of flavin using pulse voltammetry. Hematite has been used as a reducing agent for many metals and an electrochemical sensor for Riboflavin, hydroquinone, and dopamine because of its excellent adsorption capacity. Potentially, a thin hematite film can be used for microelectrodes for sensor development. We prepared hematite films on a microelectrode with a carbon fiber tip. Colloidal hematite was synthesized from iron nitrate and characterized using FTIR and EDX. In addition to microelectrode work, a hematite film was deposited on to a glassy carbon electrochemical quartz crystal microbalance (eQCM) to characterize the mechanism of deposition and physical sorption in a pH range of 5-8. Lastly, electrochemical impedance spectroscopy (EIS) was used to characterize the electrochemical processes. We found that the hematite film exhibited capacitive and resistive characteristics. We also found that the hematite film microelectrode detection limit improved compared to bare carbon fiber.