An electrical method was prepared for the measurement of Mn with trace amount in drugs and for the assessment of a sensitive method in comparison with spectrometric and atomic analyzer by a new carbon paste electrode modified with MnO₂ nanoparticles. The method was used to study the electro oxidation of manganese ions in solution by cyclic voltammetry (CV) method. The modified electrode displayed strong resolving function for the overlapping voltammetric response of Mn-ion into one well-defined peak. The potential difference between Epa and Epc was > 200 mV; this range referred to the quise-reversible mechanism. The kinetic of electrode was studied at the temperature range from 15 – 35 ℃; the data of voltamograms showed the increase of temperature caused increase of negative shift, which suggested the diffusion electron transferred in the redox process of Mn-ion oxidation. Diffusion coefficient was calculated from the Randles-Sevcik equation and was equal to 1×10^-7; the rate constant K was equal to 5.3×10^-5; the peak current of Mn-ion increased linearly with its concentration at the range of 0.5 – 4.5 ppm.

A new carbon paste electrode modified with CuO nanoparticles was prepared, and used to study the electro oxidation of copper ions in solution by cyclic voltammetry (CV) method. The modified electrode displayed strong resolving function for the overlapping voltammetric response of copper into one well-defined peak. The potential difference between Epa and Epc was > 200 mV; this range referred to the quise-reversible mechanism. The kinetic of electrode was studied at the temperature range from 15 ~ 35 °C; the data of voltamograms showed the increase of temperature caused increase of negative shift, which suggested the diffusion electron transfer in the redox process of copper oxidation. Diffusion coefficient was calculated from the Randles-Sevcik equation and was equal to 71.8 × 10^-4; the rate constant K was equal to 8.8 × 10^-7; the peak current of copper increased linearly with its concentration at the range of 0.2 ~ 2.0 ppm.

A new carbon paste electrode modified with ZnO nanoparticles was prepared and used to study the electro oxidation of zinc ions in solution by cyclic voltammetry (CV) method. The modified electrode displayed strong resolving function for the overlapping voltammetric response of zinc into one well-defined peak. The potential difference between Epa and Epc was > 200 mV, the range of which referred to the quasi-reversible mechanism. The kinetic of electrode was studied in the range of temperature 15-30 ℃. The data of voltamograms showed the negative shift increased with increase of temperature, the result of which referred to the diffusion electron transfer in redox process of zinc oxidation. Diffusion coffining was calculated from Sevcik-Randles equation and thus equaled to 1.01×10^-7. The rate constant was equal to 5.2×10^-8 and 3.3×10^-8 for oxidation and redaction respectively. And the peak current of zinc increased linearly with its concentration in the range of 2.0-20.0 ppm.