Pyridoxine determination from pharmaceutical products using two kinetic methods

This paper is a study based on kinetic determinations of pyridoxine by using its redox reaction with potassium permanganate. The stoichiometry reaction has been determined using spectrophotometrical titration. titration. In the absence of Mn(II) ions, the kinetic curve of pyridoxine shows an indication period, followed by an important increasing of reaction rate, exhibiting the auto-catalytic behavior. To increase the determination precision and to transform the oxidation reaction ill a first order one, Mn(II) has been added from the beginning into reaction mixture. Under these conditions, oxidation occurs very fast. Kinetic curves presented have no more induction periods. The correlation between pyridoxine concentration and apparent first-order rate constant obeys a Michaelis-Menten dependence, and can be described by an equation. Also it is presented a Lineawaer-Burk representation that gave a straight line.