Porous Graphitized Carbon Monolith as an Electrode Material for Probing Direct Bioelectrochemistry and Selective Detection of Hydrogen Peroxide
He, X and Zhou, L and Nesterenko, EP and Nesterenko, PN and Paull, B and Omamogho, JO and Glennon, JD and Luong, JHT, Porous Graphitized Carbon Monolith as an Electrode Material for Probing Direct Bioelectrochemistry and Selective Detection of Hydrogen Peroxide, Analytical Chemistry, 84, (5) pp. 2351-2357. ISSN 0003-2700 (2012) [Refereed Article]
For the first time, graphitized carbon particles with a high surface area have been prepared and evaluated as a new material for probing direct electrochemistry of hemoglobin (Hb). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) imaging revealed that the carbon monolithic skeleton was constructed by a series of mesopores with irregular shapes and an average pore diameter of ´5.6 nm. With a surface area of 239.6 m2/g, carbon particles exhibited three major Raman peaks as commonly
observed for carbon nanotubes and other carbon materials, i.e., the sp3
and sp2 carbon phases coexisted in the sample. A glassy carbon electrode modified with carbon monoliths and didodecyldimethylammonium bromide exhibited direct electron transfer between Hb molecules and the underlying electrode with a transfer rate constant of 6.87 s−1. The enzyme electrode displayed a pair of quasi-reversible reduction−oxidation peaks at −0.128 and −0.180 V, reflecting the well-known feature of the heme [Fe3+/Fe2+] redox couple: a surface-controlled electrochemical process with one electron transfer. This reagentless biosensing approach was capable of detecting H2O2, a simple molecule but plays an important role in analytical and biological chemistry, as low as 0.1 レM with
linearity of 0.1−60 レM and a response time of <0.8 s, comparing favorably with other carbon based electrodes (5 s).