An ionic liquid-type carbon paste electrode for electrochemical investigation and determination of calcium dobesilate

An ionic liquid-type carbon paste electrode (IL-CPE) had been fabricated by replacing non-conductive organic binders with a conductive room temperature ionic liquid, 1-pentyl-3-methylimidazolium hexafluorophosphate (PMIMPF6). The electrochemical responses of calcium dobesilate were investigated at the IL-CPE and the traditional carbon paste electrode (T-CPE) in 0.05 mol L-1 H2SO4, respectively. The results showed the superiority of IL-CPE to T-CPE in terms of provision of higher sensitivity, faster electron transfer and better reversibility. A novel method for determination of calcium dobesilate was proposed. The oxidation peak current was rectilinear with calcium dobesilate concentration in the range of 8.0 X 10(-7) to 1.0 x 10(-4) mol L-1, with a detection limit of 4.0 x 10(-7) mol L-1 (S/N = 3) by differential pulse voltammetry. The proposed method was applied to directly determine calcium dobesilate in capsule and urine samples. (c) 2007 Elsevier B.V. All rights reserved.