Quinoxalines Formed from α-1, 4 Glucans by Reaction with o-Phenylenediamine in Aqueous Alkaline Solution

Capillary electrophoresis of o-phenylenediamine derivatives (quinoxalines) of dicarbonyl sugars

Dicarbonyl sugars were separated by capillary electrophoresis as o-phenylenediamine derivatives (quinoxalines). Tetrabutylammonium bromide was used as a modifier; n-arabino-2-hexosulose (n-glucosone), D-lyxo-2-hexostdose (D-gdaCtOSOnC), 7-deoxy-L-galacto-2-hexosulose and 5-hydroxy-2,3dioxohexanal served as standards. The separation procedure was optimized with respect to pH, buffer and solute c...

Evolution Reaction in Aqueous Alkaline Solution Hydrous Nickel Oxide: Redox Switching and the Oxygen

The Oxygen Evolution Reaction on Passive Oxide Covered Transition Metal Electrodes in Aqueous Alkaline Solution. Part 1-Nickel

Various aspects of the oxygen evolution reaction (OER) at passive oxide covered polycrystalline Ni electrodes in aqueous alkaline solution were investigated using electrochemical techniques. Steady state polarisation and electrochemical impedance spectroscopy (EIS) were used to measure kinetically significant parameters including the Tafel slope and the reaction order with respect to OH activit...

Stabilization of the substrate reaction of horseradish peroxidase with o-phenylenediamine in the enzyme immunoassay.

When the horseradish peroxidase reaction is stopped with acid, the decay of unconverted hydrogen peroxide is responsible for the further oxidation of o-phenylenediamine. This leads to a time-dependent flattening of the standard curve in the enzyme immunoassay, after the reaction has been stopped. Addition of reducing agents, such as sulphite ions, to the stopping solution, prevents the further ...

Reaction of Dihydroxymethyl Radical with Molecular Oxygen in Aqueous Solution

Dihydroxymethyl radical (1) was found to react with oxygen diffusion controlled (k = 4.5 x 109 M _ 1 s 1 ) . The final products of the reaction are formic acid and 1/2 hydrogen peroxide. The precursor of H2O2 was shown to be O2' which is formed with G(02" -) = 6.3 (a value which includes the 02"~ formed by H atoms and oxygen (G(H) = 0.55)). If it is assumed that dihydroxymethylperoxyl radicals ...