Study of the electrochemical behavior of mitoxantrone and its determination at a Co–C modified ultramicroelectrode

Abstract

In 0.005 mol dm⁻³ Tris–0.05 mol dm⁻³ NaCl buffer solution (pH 7.10), the electrochemical behavior of mitoxantrone was studied by linear-sweep voltammetry and cyclic voltammetry at a Co–carbon fiber ion implantation modified ultramicroelectrode. A sensitive reduction peak was obtained. The peak potential was −0.798 V (vs. SCE), the peak current was proportional to the concentration of mitoxantrone over the range of 2.0 × 10⁻⁷–6.0 × 10⁻⁶ mol dm⁻³ and the detection limit was 4.2 × 10⁻⁸ mol dm⁻³. This method was applied to the direct determination of mitoxantrone in urine. Recoveries were in the range 95.4–105.8%. The reduction process was quasi-reversible with absorptive characteristics at a Co–C ultramicroelectrode. According to Laviron’s theory, the electrode reaction rate constant k_s and the electron transfer α of mitoxantrone were 4.4 s⁻¹ and 0.48, respectively. The composition and depth distribution of elements on the surface of the Co–C ultramicroelectrode were determined by Auger electron spectroscopy. The experiments showed that Co was implanted into the surface of the carbon fiber, and the Co–C ultramicroelectrode had good stability and reproducibility.