title: Sol-gel derived amperometric nitric oxide microsensor.
abstract: An amperometric sol-gel derived nitric oxide microsensor is described. Several silicon-based xerogel membranes are evaluated to identify the optimum composition for maximizing NO permeability while providing sufficient selectivity for NO in the presence of common interfering species. Xerogel permeability and selectivity are further manipulated as a function of reaction/processing conditions. In addition, the effects of incorporating Nafion into the xerogel matrix on sensor performance and the stability of the ensuing xerogel/Nafion hybrid film are evaluated. The optimal permselective membrane is achieved by catalyzing polycondensation of the xerogel composed of methyltrimethoxysilane and (aminoethylaminomethyl)phenethyltrimethoxysilane and Nafion with NO gas. The resulting NO microsensor exhibits a sensitivity of 0.17 +/-0.02 pA/nM (from 25 to 800 nM, r = 0.9991), detection limit of 25 nM (S/N = 3), response time of 9 s (t(95%), a NO concentration change from 400 to 500 nM), selectivity (log K(NOj) amp) of -5.8, <-6, <-6, and <-6 for j = nitrite, ascorbic acid, uric acid, and acetaminophen, and a lifetime of 8 d (82% of initial sensitivity without serious deterioration in selectivity).
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.
authors.forename: Jae Ho
authors.initials: JH
authors.lastname: Shin
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Weinman
authors.forename: Mark H
authors.initials: MH
authors.lastname: Schoenfisch
mesh_terms: D004563:Electrochemistry; D005465:Fluorocarbon Polymers / Q000737:chemistry*; D005782:Gels / Q000737:chemistry*; D008567:Membranes, Artificial; D008839:Microelectrodes; D009569:Nitric Oxide / Q000032:analysis* / Q000737:chemistry; D012680:Sensitivity and Specificity; D012825:Silicon / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors
chemical_list: D005465:Fluorocarbon Polymers; D005782:Gels; D008567:Membranes, Artificial; D009569:Nitric Oxide; C040402:perfluorosulfonic acid; D012825:Silicon