title: Development and characterization of a voltammetric carbon-fiber microelectrode pH sensor.
abstract: This work describes the development and characterization of a modified carbon-fiber microelectrode sensor capable of measuring real-time physiological pH changes in biological microenvironments. The reagentless sensor was fabricated under ambient conditions from voltammetric reduction of the diazonium salt Fast Blue RR onto a carbon-fiber surface in aprotic media. Fast-scan cyclic voltammetry was used to probe redox activity of the p-quinone moiety of the surface-bound molecule as a function of pH. In vitro calibration of the sensor in solutions ranging from pH 6.5 to 8.0 resulted in a pH-dependent anodic peak potential response. Flow-injection analysis was used to characterize the modified microelectrode, revealing sensitivity to acidic and basic changes discernible to 0.005 pH units. Furthermore, the modified electrode was used to measure dynamic in vivo pH changes evoked during neurotransmitter release in the central nervous system of the microanalytical model organism Drosophila melanogaster.
authors.affiliation: Department of Chemistry, The Pennsylvania State University, 125 Chemistry Building, University Park, Pennsylvania 16802, USA.
authors.forename: Monique A
authors.initials: MA
authors.lastname: Makos
authors.forename: Donna M
authors.initials: DM
authors.lastname: Omiatek
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Ewing
authors.forename: Michael L
authors.initials: ML
authors.lastname: Heien
mesh_terms: D000818:Animals; D002244:Carbon; D000077482:Carbon Fiber; D002490:Central Nervous System / Q000378:metabolism; D004331:Drosophila melanogaster / Q000502:physiology; D006863:Hydrogen-Ion Concentration; D008839:Microelectrodes; D018377:Neurotransmitter Agents / Q000378:metabolism; D010084:Oxidation-Reduction; D011199:Potentiometry; D011809:Quinones
chemical_list: D000077482:Carbon Fiber; D018377:Neurotransmitter Agents; D011809:Quinones; D002244:Carbon