INVESTIGATION OF MOLYBDATE(II) RUTIN COMPLEX AND THE DETERMINATION OF THE DISSOCIATION-CONSTANT OF RUTIN IN WATER ETHANOL MIXTURE

By the application of the spectrophotometric methods the composition of the complex and by the pH-metric method the reaction of complex formation, were determined. It was found that a complex MoO3C27H26O16H2(2-) was formed. The dissociation constant of rutin was determined pH-metrically at (20.0 +/- 0.1)-degrees-C (k(d) = 8.64 x 10(-15)). The concentration stability constant of the complex was determined by Bent-French and Bjerrum's methods, at various pH-values. Conditions are also given for the spectrophotometric determination of rutin by means of molybdate(II) as well as the accuracy of the method proposed. All spectrophotometric measurements were done in 70% ethanol, at pH = 6.30 +/- 0.05 and ionic strength 0.015, whereas the determination of rutin was carried out in 50% ethanol, at pH = 6.40 +/- 0.05, at room temperature (20-degrees-C) and the same ionic strength.