The redox profile obtained from electrochemically oxidised carbon fibre was exploited as a foundation from which to design a reusable pH probe. X-ray photoelectron spectroscopy of the surface after anodisation revealed an increase in the population of endogenous quinone moieties. Square wave voltammograms recorded in various buffer solutions (pH 3–9) yielded a distinct and unambiguous oxidation process through which to ascribe the peak potential — with the latter found to shift in a sub-Nernstian (− 0.052 V/pH) manner. The design of a discrete 2-electrode reusable probe which provides a rapid assessment of pH is described and a preliminary characterisation of the electrochemical performance is critically assessed.
Anderson, A., Phair, J., Benson, J., Meenan, BJ., & Davis, J. (2014). Investigating the use of endogenous quinoid moieties on carbon fibre as means of developing micro pH sensors. Materials Science and Engineering C, 43, 533-537. https://doi.org/10.1016/j.msec.2014.07.038