Oxidation of L-Ascorbic Acid in Copper(II) Ion - Catalyzed Polyvinylpyrrolidone Solutions

Angi S., Kihc H., Imer F.

9th Eurasia Conference on Chemical Sciences, Antalya, Türkiye, 9 - 13 Eylül 2006, ss.319-320 identifier


The effects of Cu (II) ion and polyvinylpyrrolidone (PVP) (K-30) concentrations on the oxidation kinetics of ascorbic acid (Vitamin C: H,A) in aerated and acetate buffered solution (pH = 4.5) have been investigated at 25 degrees C. The study was carried out in the concentration range of PVP between 0.2% and 0.6%, and in the concentration range of Cu (II) between 0.785 and 3.14 x 10(-7) M. The initial concentrations of H(2)A were 2.8-11.3 x 10(-5) M. The changes in H(2)A concentrations during the reactions were determined from absorbance measurements at a wavelength of 264.0 nm, using direct UV spectrophotometric method. Molecular weight (MW) of the PVP has been redetermined as a mean MW, using viscosimetric method.