Determination of Calcium Dobesilate by Differential Pulse Voltammetry at a Disposable Pencil Graphite Electrode

摘要

The electrochemistry of calcium dobesilate was investigated by recording cyclic and differential pulse voltammograms at a disposable and inexpensive pencil graphite electrode (PGE). Cyclic voltammograms of calcium dobesilate recorded in 0.1 M HCl showed a pair of well-defined redox peaks at the PGE indicating excellent electro-chemical activity. The oxidation peak current of the calcium dobesilate was used for its determination by recording its differential pulse voltammograms. The anodic peak current increased linearly with the concentration of calcium dobesilate in the range from 0.2 to 100 mu M with a detection limit 0.065 mu M. Relative standard deviations of 2.0 and 1.1% for innerday and 3.6 and 2.0% for intraday precision were obtained for three successive determinations of 0.5 and 10 mu M calcium dobesilate, respectively, which indicates acceptable repeatability and reproducibility. This voltammetric method was also successfully applied to the direct determination of calcium dobesilate in pharmaceutical samples. The effect of various interfering compounds on the calcium dobesilate peak current was studied. Thus, an unmodified PGE provides a new, promising, and alternative method of achieving sensitive, inexpensive, and selective determination of calcium dobesilate.