Electrochemical behavior and determination of rutin on a pyridinium-based ionic liquid modified carbon paste electrode

In this paper the electrochemical behavior of rutin on a pyridinium-typed ionic liquid modified carbon paste electrode (IL-CPE) was investigated and further used for rutin sample determination. The IL-CPE showed strong electrocatalytic effects to the oxidation of rutin. In phosphate buffer solution (PBS, pH 2.5; 0.1 M) a pair of well-defined cyclic voltammetric redox peaks of rutin appeared with the redox peak located at 512 mV (Epa) and 448 mV (Epc) (vs. SCE), respectively. The redox peak current was increased about 27.5 times more than that on traditional carbon paste electrode (CPE). The electrochemical parameters of rutin on the IL-CPE were calculated with the results of the charge transfer coefficient (alpha), the number of electron transfer (n) and the electrode reaction rate constant (k(s)) as 0.53, 1.80 and 2.39 s(-1), respectively. The cathodic peak currents increased linearly with the concentration of rutin in the range from 5.0 x 10(-7) to 1.0 x 10(-4) M with the detection limit as 3.58 x 10(-7) M (3 alpha). The relative standard deviation (RSD) of 10 successive detection of 5.0 x 10(-5) M rutin was 4.2%. The method was successfully applied to the determination of rutin content in tablets samples with good recovery. The modified electrode showed good stability and reproducibility without the influence of the coexisting substances. (C) 2008 Elsevier B.V. All rights reserved.