title: Voltammetric pH sensor based on an edge plane pyrolytic graphite electrode.
abstract: A simple sensor for pH determination is reported using unmodified edge plane pyrolytic graphite (EPPG) electrodes. The analysis is based on the electro-reduction of surface quinone groups on the EPPG which was characterised using cyclic voltammetry (CV) and optimised with square-wave voltammetry (SWV). Under optimised conditions, a linear response is observed between the peak potential and pH with a gradient of ∼59 mV per pH (at 25 °C), which corresponds well with Nernstian behaviour based on a 2 proton, 2 electron system over the aqueous pH range 1.0 to 13.0. As such, an EPPG is suggested as a reagent free and robust pH sensing material.
authors.affiliation: Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, UK. richard.compton@chem.ox.ac.uk.
authors.forename: Min
authors.initials: M
authors.lastname: Lu
authors.forename: Richard G
authors.initials: RG
authors.lastname: Compton
mesh_terms: D055664:Electrochemical Techniques / Q000295:instrumentation*; D004566:Electrodes; D006108:Graphite; D006863:Hydrogen-Ion Concentration
chemical_list: D006108:Graphite