Featured Molecules: Ascorbic Acid and Methylene Blue
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چکیده
منابع مشابه
Hydrogen peroxide and hydroxyl radical formation by methylene blue in the presence of ascorbic acid.
Using ESR we have demonstrated the formation of the ascorbate free radical from sodium ascorbate, methylene blue and light. In oxygen uptake experiments we have observed the production of hydrogen peroxide while spin trapping experiments have revealed the iron catalyzed production of the hydroxyl free radical in this system. The presence of this highly reactive radical suggests that it could be...
متن کاملMethylene Blue Immobilized on Cellulose Acetate with Titanium Dioxide: an Application as Sensor for Ascorbic Acid
Neste trabalho, o corante azul de metileno foi imobilizado na superfície do acetato de celulose modificado com dióxido de titânio produzindo um material híbrido sólido denominado de CA-TiO 2 MB. O experimento produziu uma quantidade de 1,8 mmol g de TiO 2 incorporado no acetato de celulose e uma quantidade de 0,170 0,005 mmol g de azul de metileno adsorvido na superfície do CA-TiO 2 . Um eletro...
متن کاملDetermination of trace amounts of copper(II) by using catalytic redox reaction between methylene blue and ascorbic acid.
A sensitive and selective kinetic-spectrophotometric method is proposed for the determination of microg mL(-1) amounts of Cu2+ based on its catalytic effect on the oxidation of L-ascorbic acid by Methylene Blue in a strongly acidic medium. The reaction is monitored spectrophotometrically by measuring the decrease in color intensity of Methylene Blue at 665 nm. The analysis of Cu2+ ion is perfor...
متن کاملThe Influence of Transition Metal Ions on the Kinetics of Ascorbic Acid Oxidation by Methylene Blue in Strongly Acidic Media
The oxidation of ascorbic acid (Vitamin C) is a very important redox reaction, as it has interesting biological properties and is also a powerful reductant. Ascorbic acid is a lactone with a 2,3-endiol group. The enolic group imparts acidity to the molecule; the enol group at position 3 has a pKa of 4.1 and the enol at position 2 has a pKa of 11.6. It is very effective as a reducing agent and i...
متن کاملFlow Injection Amperometric Determination of Ascorbic Acid Using a Photoelectrochemical Reaction after Immobilization of Methylene Blue on Muscovite
The photoelectrochemical determination of ascorbic acid (AA) was studied based on the photochemical reduction of methylene blue (MB) in 0.1 M phosphate buffer (pH 7.0). MB was used as a redox mediator for the modification of a carbon paste electrode (CPE) due to its facile reducible-oxidizible behaviour. Muscovite, which has a layered structure, was found to be a good and stable supporting mate...
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ژورنال
عنوان ژورنال: Journal of Chemical Education
سال: 2003
ISSN: 0021-9584,1938-1328
DOI: 10.1021/ed080p584