Pt Nanoparticle-Modified Carbon Fiber Microelectrode for Selective Electrochemical Sensing of Hydrogen Peroxide

摘要

We report a simple approach to the production of carbon fiber-based amperometric microbiosensors for selective detection of hydrogen peroxide (H2O2), which was achieved by electrometallization of carbon fiber microelectrodes (CFMs) by electrodeposition of Pt nanoparticles. The Pt-carbon hybrid sensing interface provided a sensitivity of 7711 +/- 587 mu A . mM(-1) . cm(-2), a detection limit of 0.53 +/- 0.16 mu M (S/N=3), a linear range of 0.8 mu M-8.6 mM, and a response time of <2 sec. The morphologies of the Pt nanoparticle-modified CFMs were characterized by scanning electron microscopy. To achieve selectivity, permseletive layers, polyphenylenediamine (PPD) and Nafion, were deposited resulting in exclusion of the anionic and cationic interferents, ascorbic acid and dopamine, respectively, at their physiologically relevant concentrations. The resultant sensors displayed a sensitivity to hydrogen peroxide of 1381 +/- 72 mu A . mM(-1) . cm(-2), and a detection limit of 0.86 +/- 0.19 mu M (S/N=3). This simple and rapid metallization method converts carbon fiber microelectrodes, which are readily accessible, to microscale Pt electrodes in 2 min, providing a platform for oxidase-based amperometric biosensors with improved spatial resolution over more commonly used platinum electrode array microprobes.