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Comparative Study of Different Cross-Linking Agents for the Immobilization of F...
Pauliukaite, Rasa; Ghica, Mariana Emilia; Fatibello-Filho, Orlando; Brett, Christopher M. A.The effectiveness of immobilization of functionalized carbon nanotubes into chitosan using different cross-linking agents has been evaluated. The cross-linkers used were glyoxal (GO), glutaraldehyde (GA), epichlorohydrin (ECH), and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide together with N-hydroxysuccinimide (EDC-NHS), and the nanotubes were retained on graphite epoxy resin composite electrodes. The nanotub...
An improved biosensor for acetaldehyde determination using a bienzymatic strate...
Ghica, Mariana Emilia; Pauliukaite, Rasa; Marchand, Nicolas; Devic, Eric; Brett, Christopher M.A.Improved biosensors for acetaldehyde determination have been developed using a bienzymatic strategy, based on a mediator-modified carbon film electrode and co-immobilisation of NADH oxidase and aldehyde dehydrogenase. Modification of the carbon film electrode with poly(neutral red) mediator resulted in a sensitive, low-cost and reliable NADH detector. Immobilisation of the enzymes was performed using encapsulat...
Development of Novel Glucose and Pyruvate Biosensors at Poly(Neutral Red) Modif...
Ghica, Mariana Emilia; Brett, Christopher M. A.Amperometric biosensors based on the corresponding oxidase enzyme with poly(neutral red) redox mediator have been developed for the determination of glucose and pyruvate. The enzymes have been immobilized on top of poly(neutral red) modified carbon film electrodes with glutaraldehyde as the cross-linking agent. The biosensors were characterized by cyclic voltammetry and by electrochemical impedance spectroscopy...
A glucose biosensor using methyl viologen redox mediator on carbon film electrodes
Ghica, Mariana Emilia; Brett, Christopher M.A.A new methyl viologen-mediated amperometric enzyme electrode sensitive to glucose has been developed using carbon film electrode substrates. Carbon film electrodes from resistors fabricated by pyrolytic deposition of carbon were modified by immobilization of glucose oxidase through cross-linking with glutaraldehyde in the presence of bovine serum albumin. The mediator, methyl viologen, was directly immobilised ...
Electrochemical Oxidation of Rutin
Ghica, Mariana-Emilia; Brett, Ana Maria OliveiraAn electrochemical investigation of rutin oxidation on a glassy carbon electrode was carried out using cyclic voltammetry, differential pulse voltammetry and square-wave voltammetry over a wide pH interval. The electrochemical oxidation is a complex process, which proceeds in a cascade mechanism, related with the 4-hydroxyl groups of the rutin molecule. The catechol 3prime,4prime-dihydroxyl group is the first t...
A new, improved sensor for ascorbate determination at copper hexacyanoferrate m...
Pauliukaite, Rasa; Ghica, Mariana Emilia; Brett, Christopher M. A.A new, improved sensor for the electrocatalytic determination of ascorbate has been developed that has both a low applied operating potential and a low detection limit. The sensor was constructed by depositing copper hexacyanoferrate film either electrochemically or chemically onto carbon film electrode, and it was then characterised by cyclic voltammetry and electrochemical impedance spectroscopy. Chemically d...
Electrochemical Oxidation of Quercetin
Brett, Ana Maria Oliveira; Ghica, Mariana-EmiliaThe mechanism of electrochemical oxidation of quercetin on a glassy carbon electrode has been studied using cyclic, differential pulse and square-wave voltammetry at different pH. It proceeds in a cascade mechanism, related with the two catechol hydroxyl groups and the other three hydroxyl groups which all present electroactivity, and the oxidation is pH dependent. Quercetin also adsorbs strongly on the electro...
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