Application of 2-(3,4-dihydroxyphenyl)-1,3-dithialone self-assembled monolayer on gold electrode as a nanosensor for electrocatalytic determination of dopamine and uric acid.

The electrooxidation of dopamine (DA), uric acid (UA) and their mixture on a gold electrode modified by a self-assembled monolayer of 2-(3,4-dihydroxyphenyl)-1,3-dithialone has been studied by cyclic voltammetry (CV), chronoamperometry and differential pulse voltammetry (DPV). CV was used to investigate the redox properties of the modified electrode at various scan rates and the apparent charge transfer rate constant (k(s)), and transfer coefficient (α) were calculated. The mediated oxidation of DA at the modified electrode under the optimum condition (pH = 7.

Simultaneous and selective voltammetric determination of , and at a nanoparticles modified paste electrode.

A new carbon paste electrode modified with ZrO2 nanoparticles (ZONMCPE) was prepared, and used to study the electrooxidation of epinephrine (EP), acetaminophen (AC), folic acid (FA) and their mixtures by electrochemical methods. The modified electrode displayed strong resolving function for the overlapping voltammetric responses of EP, AC and FA into three well-defined peaks. The potential differences between EP - AC, AC - FA and EP - FA were 210, 290 and 500 mV respectively.

Frequency effects on the surface coverage of nitrophenyl films ultrasonically grafted onto indium tin oxide.

The covalent attachment of various organic molecules on conductive supports including indium tin oxide (ITO) using diazonium chemistry has been known for many years. A commonly used method to achieve this is the electrochemical reduction of diazonium compounds leading to radicals, followed by binding of the radicals to the support. In the present report, an alternative method using ultrasound at different frequencies (20, 582, 863, and 1142 kHz) to induce the surface grafting of nitrobenzene diazonium onto an ITO surface is described.

A highly sensitive nanostructure-based electrochemical sensor for electrocatalytic determination of norepinephrine in the presence of acetaminophen and tryptophan.

A new electrochemical sensor for the determination of norepinephrine (NE), acetaminophen (AC) and tryptophan (Trp) is described. The sensor is based on carbon paste electrode (CPE) modified with 3,4-dihydroxybenzaldehyde-2,4-dinitrophenylhydrazone (DDP) and takes the advantages of carbon nanotubes (CNTs), which makes the modified electrode highly sensitive for the electrochemical detection of these compounds. Cyclic voltammetry (CV) at various scan rates was used to investigate the redox properties of the modified electrode.

Electrocatalytic oxygen reduction on functionalized gold nanoparticles incorporated in a hydrophobic environment.

The electrocatalytic properties of gold nanoparticles covalently capped with a monolayer film of 1,4-decylphenyl groups for oxygen reduction in an alkaline solution have been studied. Functionalized nanoparticles were adsorbed on a film of the same capping ligand previously grafted to a glassy carbon electrode. The molecular film-nanoparticle assembly was characterized by cyclic voltammetry and XPS.

Electrochemical reduction of oxygen on nanoparticulate gold electrodeposited on a molecular template.

The reduction of oxygen on gold electrodeposited on an organic template has been investigated. The template consisted of reduced 4-nitrophenyl groups attached to glassy carbon (GC) by the electrochemical reduction of the corresponding diazonium compound. The electrode modified by this Au nanostructured film shows electrocatalytic properties for the oxygen reduction reaction (ORR) different from those of bulk Au, GC or GC grafted with 4-nitrophenyl groups.

Synthesis of metal nanoparticles stabilized by metal-carbon bonds.

A new method for the preparation of metal nanoparticles in organic media is proposed. This is based on the formation of metal-carbon bonds after reduction of the corresponding diazonium derivative of the capping ligand. The particles are very stable due to the strong metal-ligand covalent bond, and the proposed method appears to be an alternative for the preparation of monolayer-protected metal nanoparticles when the formation of metal-sulfur or metal-nitrogen bonds needs to be avoided.