Anodic Oxidation of m-terphenyl thio-, seleno-and telluroethers: Lowered oxidation potentials due to chalcogen.•••π interaction

The electrochemistry of m-terphenylthio-, seleno-, and telluroethers was studied using cyclic voltammetry in acetonitrile. All of the compounds studied showed irreversible oxidations. The first oxidation potentials for the thio- and selenoethers are less positive than expected. This facilitation in oxidation is ascribed to through-space S···π and Se···π interaction, respectively, on removal of an electron. No evidence for a comparable effect was found for the phenyltelluro-ethers studied

Electrochemical and electrophoretic deposition of enzymes:Principles, differences and application in miniaturized biosensor and biofuel cell electrodes

Recent advances in nano-biotechnology have made it possible to realize a great variety of enzyme electrodes suitable for sensing and energy applications. In coating miniaturized electrodes with enzymes, there is no doubt that most of the available deposition processes suffer from the difficulty in depositing uniform and reproducible coatings of the active enzyme on the miniature transducer element. This mini-review highlights the promising prospects of two techniques, electrochemical deposition (ECD) and electrophoretic deposition (EPD), in enzyme immobilization onto miniaturized electrodes and their use as biosensors and biofuel cells. The main differences between ECD and EPD are described and highlighted in the sense to make it clear to the reader that both techniques employ electric fields to deposit enzyme but the conditions from which each process is achieved and hence the mechanisms are quite different. Many aspects dealing with deposition of enzyme under ECD and EPD are considered including surface charge of enzyme, its migration under the applied electric field and its precipitation on the electrode. Still all issues discussed in this mini-review are generic and need to be followed in the future by extensive theoretical and experimental research analysis. Finally, the advantages of ECD and EPD in fabrication of miniature biosensor and biofuel cell electrodes are described and discussed. (c) 2014 Elsevier B.V. All rights reserved

Électrons dans la Matière et Lien avec l’Oxydoréduction: Concepts de Base avec Questions et Problèmes Résolus (Section 2) (French Edition)

En tant que professeure de chimie physique, j'ai remarqué que les étudiants, même dans des classes avancées, ont des difficultés à comprendre les bases d’oxydoréduction (chimie redox ou électrochimie). Cette Section 2 résume certains principes fondamentaux relatifs aux électrons incluant la structure atomique, le tableau périodique, les principaux modèles électroniques, la configuration électronique et les niveaux d'énergie des électrons. En particulier, l'identification de la configuration électronique des éléments et la visualisation des électrons dans leurs couches externes sont des concepts très importants pour comprendre les processus d'oxydoréduction. Pour clarifier davantage les concepts discutés, un grand nombre de questions et problèmes avec réponses détaillées sont fournis. La plupart de ces questions sont formulées par des étudiants comme vous. Je crois que cette Section 2 aiderait grandement les étudiants avec des niveaux variant de l'école secondaire aux cours universitaires avancés

A Better Way to Learn Redox Chemistry Part 1: Summarized Principles and Over 250 Answered Questions and Problems: Electrochemistry Part 1: Summarized Basics and Over 250 Resolved Exercises

This short book (part 1) summarizes some basics of redox chemistry (electrochemistry) in solution. Each section of the book contains concise and clear referenced summaries of redox concepts. Over 250 answered questions and problems are provided to further clarify the discussed principles

Une Meilleure Façon d'Apprendre l’Oxydoréduction Partie 1: Résumés des Principes et Plus de 250 Questions et Problèmes Résolus (French Edition)

Ce petit livre (Partie 1) résume quelques principes de chimie d’oxydoréduction (électrochimie) en solution. Chaque section du livre contient des résumés référencés, concis et clairs des concepts d’oxydoréduction. Plus de 250 questions et problèmes avec solution sont fournis afin de clarifier davantage les principes discutés

Principles of Redox Reactions: Basics Concepts with Resolved Questions and Problems (Section 3)

As a teacher of physical chemistry, I noticed that students, even in advanced classes, have difficulties in understanding the basics of redox chemistry. In this Section 3, I attempted to discuss some fundamental principles related to redox processes, by focusing on the species that might lose or gain electrons, determination of the oxidation numbers (or states) of atoms in compounds, and ways of balancing redox reactions. To further clarify the discussed concepts, numerous questions and problems with detailed answers are provided. Most of these questions are formulated by students like you. I believe that this Section 3 would greatly help students with levels varying from high school to advanced university classes

Corrigendum to "AC-electrophoretic deposition of glucose oxidase" (vol 25, no 1, pg 191-197, 2009)

status: publishe

Electrons in Matter and Link to Redox Chemistry: Basics Concepts with Resolved Questions and Problems (Section 2)

As a teacher of physical chemistry, I noticed that students, even in advanced classes, have difficulties in understanding the basics of redox chemistry. In this Section 2, I attempted to summarize some fundamental principles related to electrons, including the atomic structure, periodic table, main electronic models, electronic configuration, and the energy levels of electrons. The identification of the electronic configurations of elements and visualization of electrons in their outer shells are very important concepts in understanding redox processes. To further clarify the discussed concepts, numerous questions and problems with detailed answers are provided. Most of these questions are formulated by students like you. I believe that this Section 2 would greatly help students with levels varying from high school to advanced university classes

Applications de l’Équation de Nernst: Concepts de Base avec Questions et Problèmes Résolus (Section 6) (French Edition)

En tant que professeure de chimie physique, j'ai remarqué que les étudiants, même dans des classes avancées, ont des difficultés à comprendre les bases d’oxydoréduction (chimie redox ou électrochimie). Section 6 discute certaines applications de l'équation de Nernst dans les systèmes électrochimiques, y compris l'énergie (consommation ou génération), corrosion, titrages redox, ainsi que l'étude des processus de solubilité, précipitation et complexation. Pour clarifier davantage les concepts discutés, un grand nombre de questions et problèmes avec réponses détaillées sont fournis. La plupart de ces questions sont formulées par des étudiants comme vous. Je crois que cette Section 6 aiderait grandement les étudiants avec des niveaux variant de l'école secondaire aux cours universitaires avancés

Two-enzyme lactose biosensor based on ß-galactosidase and glucose oxidase deposited by AC-electrophoresis: Characteristics and performance for lactose determination in milk

In this paper, we have investigated the deposition of two enzymes beta-galactosidase (beta-Gal) and glucose oxidase (GOx) using alternating current electrophoretic deposition (AC-EPD) to manufacture a lactose sensor. Using the optimal deposition parameters and optimal testing conditions, the sensor has a sensitivity up to 111 nA/mM mm(2). This sensitivity is high considering the low activity of the enzymes employed in this study (9 units/mg for beta-Gal and 5.6 units/mg for GOx). The sensor has a large linear range up to 14 mM lactose, fast response time (similar to 8 s) and reasonable stability without employing any stabilizers or outer polymer membrane. In addition, it is easy and simple to manufacture, highly reproducible and cheap because low activity enzymes are used. The sensor was tested to determine lactose in milk samples and is demonstrated to be accurate.status: publishe