Search results for "Amperometry"
showing 8 items of 28 documents
Chronoamperometry of prussian blue films on ITO electrodes: Ohmic drop and film thickness effect
1999
Abstract The chronoamperograms associated with the reduction of prussian blue films deposited onto indium tin oxide (ITO) electrodes to the Everitt’s salt form, are influenced by the ohmic drop effect. These chronoamperometric curves have been simulated by means of a numerical finite difference model which is able to explain their shape and their dependence on the thickness of the film and on the uncompensated resistance. An analytical expression which describes the dependence of current against time at initial times considering the ohmic drop effect has also been proved when applied to these chronoamperometric curves at short times.
Electron transfer mechanism in Shewanella loihica PV-4 biofilms formed at graphite electrode
2012
Abstract Electron transfer mechanisms in Shewanella loihica PV-4 viable biofilms formed at graphite electrodes were investigated in potentiostat-controlled electrochemical cells poised at oxidative potentials (0.2 V vs. Ag/AgCl). Chronoamperometry (CA) showed a repeatable biofilm growth of S. loihica PV-4 on graphite electrode. CA, cyclic voltammetry (CV) and its first derivative shows that both direct electron transfer (DET) mediated electron transfer (MET) mechanism contributes to the overall anodic (oxidation) current. The maximum anodic current density recorded on graphite was 90 μA cm − 2 . Fluorescence emission spectra shows increased concentration of quinone derivatives and riboflavi…
Acid versus base peptization of mesoporous nanocrystalline TiO2 films: functional studies in dye sensitized solar cells
2005
We report an analysis of the influence of acid/base conditions employed in the synthesis of TiO2 nanoparticles upon the performance of dye sensitised photoelectrochemical solar cells fabricated from these particles. The functional properties of the TiO2 nanoparticles in these devices are investigated by potential step chronoamperometry, transient laser spectroscopy, and photovoltaic device characterisation. We find that base peptization conditions employed in the sol–gel fabrication of the TiO2 nanoparticles result in a reduction in film electron density under negative applied bias, correlated with slower interfacial recombination losses and a higher device open circuit voltage.
A thin layer-based amperometric enzyme immunoassay for the rapid and sensitive diagnosis of respiratory syncytial virus infections
2012
Abstract A simple electrochemical sandwich immunoassay involving a polystyrene microarray slide coated with monoclonal capture antibodies and carbon screen-printed sensors (SPS) was designed for the rapid diagnosis of respiratory syncytial virus (RSV). The detection of the antibody-antigen complex formation relied on the use of a horseradish peroxidase conjugate. Its chronoamperometric measurement detection was performed by confining a droplet of H 2 O 2 /3,3',5,5'-tetramethylbenzidine enzyme substrate/mediator solution within a thin layer between one spot of the microarray and the surface of one screen-printed electrochemical cell. The accumulation of the enzyme product in the thin film of…
Détection ampérométrique d'Escherichia coli (totaux et producteurs de beta-lactamase à spectre étendu (BLSE) et d'Enterococcus spp. dans les systèmes…
2017
Treated wastewaters discharged from wastewater treatment plants (WWTP) and livestock effluents are the main sources of contamination of aquatic environments and of agricultural soils by human and animal fecal micro-organisms. Contaminated waters, especially bathing waters, may present a sanitary risk for humans if the concentrations of fecal micro-organisms are high, thus indicating the potential presence of pathogenic and/or antibiotic resistant strains. Soils and crops also can be contaminated by these micro-organisms when treated wastewaters are used to irrigate cultivated soils. Consequently, microbiological quality controls are mandatory for bathing waters and treated wastewaters to ma…
Coupling of proton translocation through ATPase incorporated into supported lipid bilayers to an electrochemical process
1997
Abstract H+-ATPase is incorporated into solid-supported lipid bilayers separated from the gold support by a peptide spacer. The translocation of protons across the lipid film to the inner side is coupled to the discharge of protons at the gold surface. The overall process is investigated by square wave voltammetry (SWV) and double potential-pulse chronoamperometry (CA). As a result, the formation of a proton gradient is monitored by SWV whereas currents measured by CA monitor the stationary state when the enzyme activity is directly coupled to the charge transfer at the electrode. These currents markedly depend on the number of ATPases present in the bilayer.
Application of polydopamine functionalized zinc oxide for glucose biosensor design
2021
Zinc oxide (ZnO) nanostructures are widely used in optical sensors and biosensors. Functionalization of these nanostructures with polymers enables optical properties of ZnO to be tailored. Polydopamine (PDA) is a highly biocompatible polymer, which can be used as a versatile coating suitable for application in sensor and biosensor design. In this research, we have grown ZnO-based nanorods on the surface of ITO-modified glass-plated optically transparent electrodes (glass/ITO). Then the deposition of the PDA polymer layer on the surface of ZnO nanorods was performed from an aqueous PDA solution in such a way glass/ITO/ZnO-PDA structure was formed. The ZnO-PDA composite was characterized by S…
Amperometric Biosensor and Front-End Electronics for Remote Glucose Monitoring by Crosslinked PEDOT-Glucose Oxidase
2018
Focusing on the interplay between interface chemistry, electrochemistry, and integrated electronics, we show a novel low-cost and flexible biosensing platform for continuous glucose monitoring. The amperometric biosensing system features a planar three-electrode structure on a plastic substrate, and a wireless near-field communication-powered electronic system performing sensor analog front-end, A/D conversion, digital control, and display tasks. The working electrode is made of electropolymerized poly (3,4-ethylenedioxythiophene) film onto a polyethylene terephthalate/gold electrode followed by immobilization of cross-linked glucose oxidase by glutaraldehyde. The advantages offered by such…