Microscopic Measurement of pH with Iridium Oxide Microelectrodes
- 13 September 2000
- journal article
- Published by American Chemical Society (ACS) in Analytical Chemistry
- Vol. 72 (20) , 4921-4927
- https://doi.org/10.1021/ac000383j
Abstract
Microscopic pH electrodes were produced by deposition of hydrous iridium oxide onto carbon fiber microelectrodes. The electrodes exhibit two linear regions of potentiometric response between pH 2-6 and pH 6-12. The electrodes respond to pH changes within 50 ms, and an equilibrium value is reached within 30 s. By using these electrodes as probes in the scanning electrochemical microscope, dynamic pH changes occurring at or near a surface can be measured and pH maps of the surface can be generated. Vertical pH profiles and images of pH were obtained at substrates where electrochemical (oxidation and reduction of H2O2, hydrogen evolution) or enzymatic (glucose oxidase) reactions involving proton transfers occur.Keywords
This publication has 21 references indexed in Scilit:
- Cylindrically Etched Carbon-Fiber Microelectrodes for Low-Noise Amperometric Recording of Cellular SecretionAnalytical Chemistry, 1998
- Covalent Modification of Carbon Surfaces by Aryl Radicals Generated from the Electrochemical Reduction of Diazonium SaltsJournal of the American Chemical Society, 1997
- Upper Yield Stress of Si Crystals at High TemperaturesJournal of the Electrochemical Society, 1996
- Sputtered thin-film pH electrodes of platinum, palladium, ruthenium, and iridium oxidesSensors and Actuators B: Chemical, 1995
- Characterization of submicron-sized carbon electrodes insulated with a phenol-allylphenol copolymerAnalytical Chemistry, 1992
- Iridium oxide thin-film stability in high-temperature corrosive solutionsSensors and Actuators B: Chemical, 1991
- Enzyme-modified carbon-fiber microelectrodes with millisecond response timesJournal of the American Chemical Society, 1991
- Metal-Metal Oxide and Metal Oxide Electrodes as pH SensorsCritical Reviews in Analytical Chemistry, 1988
- Bevelled carbon-fiber ultramicroelectrodesAnalytica Chimica Acta, 1986
- Surface and bulk processes at oxidized iridium electrodes—I. Monolayer stage and transition to reversible multilayer oxide film behaviourElectrochimica Acta, 1983