Determination of Rutin in Pharmaceutical Compounds and Tea Using Cathodic Adsorptive Stripping Voltammetry

Abstract

A new sensitive electrochemical procedure is presented for the determination of Rutin based on the accumulation of Rutin onto the surface of hanging mercury drop electrode for 80 s. Then the preconcentrated Rutin-complex was analyzed by cathodic stripping square-wave voltammetry. The effect of various parameters such as pH, concentration of copper, accumulation potential, accumulation time and scan rate on the sensitivity were studied. The optimum conditions for determination of Rutin include pH 6.0, 6.0 ng mL−1 copper(II) concentration, accumulation potential of −0.30 V and scan rate of 0.40 V s−1. Under the optimum conditions and for an accumulation time of 80 s, the measured peak current at about −0.03 V is proportional to the concentration of Rutin over the range of 2.0–85.0 nM. The practical limit of detection is 0.5 nM. The relative standard deviations for six replicate analyses of 10 and 50 nM Rutin are 1.8% and 1.7%, respectively. The method was applied to the determination of Rutin in synthetic, tea, and pharmaceutical samples with satisfactory results. The diffusion coefficient, complex formation constant and number of electron transfer of Rutin–Cu(II) complex was also estimated.