title: Cavity transport effects in generator-collector electrochemical analysis of nitrobenzene.
abstract: Two types of generator-collector electrode systems, (i) a gold-gold interdigitated microband array and (ii) a gold-gold dual-plate microtrench, are compared for nitrobenzene electroanalysis in aerated aqueous 0.1 M NaOH. The complexity of the nitrobenzene reduction in conjunction with the presence of ambient levels of oxygen in the analysis solution provide a challenging problem in which feedback-amplified generator-collector steady state currents provide the analytical signal. In contrast to the more openly accessible geometry of the interdigitated array electrode, where the voltammetric response for nitrobenzene is less well-defined and signals drift, the voltammetric response for the cavity-like microtrench electrode is stable and readily detectable at 1 μM level. Both types of electrode show oxygen-enhanced low concentration collector current responses due to additional feedback via reaction intermediates. The observations are rationalised in terms of a "cavity transport coefficient" which is beneficial in the dual-plate microtrench, where oxygen interference effects are suppressed and the analytical signal is amplified and stabilised.
authors.affiliation: Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK. F.Marken@bath.ac.uk.
authors.forename: Grace E M
authors.initials: GE
authors.lastname: Lewis
authors.forename: Sara E C
authors.initials: SE
authors.lastname: Dale
authors.forename: Barbara
authors.initials: B
authors.lastname: Kasprzyk-Hordern
authors.forename: Anneke T
authors.initials: AT
authors.lastname: Lubben
authors.forename: Edward O
authors.initials: EO
authors.lastname: Barnes
authors.forename: Richard G
authors.initials: RG
authors.lastname: Compton
authors.forename: Frank
authors.initials: F
authors.lastname: Marken
mesh_terms: D002138:Calibration; D055664:Electrochemical Techniques / Q000592:standards; D004566:Electrodes; D005295:Ferrocyanides / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D008962:Models, Theoretical; D009578:Nitrobenzenes / Q000032:analysis* / Q000592:standards; D010084:Oxidation-Reduction; D012972:Sodium Hydroxide / Q000737:chemistry
chemical_list: D005295:Ferrocyanides; D009578:Nitrobenzenes; D012972:Sodium Hydroxide; D006046:Gold; C036077:nitrobenzene; C020354:hexacyanoferrate II