Sensitive determination of colchicine at carbon paste electrode doped with multiwall carbon nanotubes

Abstract

A carbon paste electrode doped with multiwall carbon nanotubes was constructed for the determination of colchicine. Cyclic voltammetry, differential pulse voltammetry and chronocoulometry have been used to investigate the electrochemical response characteristics and the kinetics parameters of colchicine on the proposed voltammetric sensor. Results show that the doped multiwall carbon nanotubes can greatly promote the electrochemical response of colchicine. Under optimum conditions, the oxidation current of colchicine was proportional to the concentration of colchicine in a wide linear range from 1.0 × 10⁻⁸ mol L⁻¹ to 2.5 × 10⁻⁵ mol L⁻¹ with a low detection limit of 8.0 × 10⁻⁹ mol L⁻¹ in 0.15 mol L⁻¹ H₂SO₄ (pH 0.8). The newly recommended sensor shows several merits including extreme simplicity, wide linear range, low detection limit, good stability and excellent reproducibility. Furthermore, it was successfully employed for the determination of colchicine in pharmaceutical formulations with satisfactory results.