SPECTROPHOTOMETRIC INVESTIGATION OF THE PD(II)-QUERCETIN COMPLEX IN 50-PERCENT ETHANOL

Composition and stability constant of the Pd(II)-quercetin complex wer e determined by suitable spectrophotometric methods and pH-metric meas urements in 50% Ethanol. It was found that the pd(2+) ion and querceti n form a 1:1 complex in which Pd2+ is linked to quercetin through the carbonyl and the 3-hydroxyl group. The stability constant log beta(1) ranged from 6.05 at pH = 5.00 to 4.96 at pH = 6.50. The conditions for the spectrophotometric determination of quercetin by means of complex formation were investigated. Beer's law was obeyed up to 5.00 x 10(-5 ) M quercetin.