Electrochemical Investigation of Coenzyme Q ₁₀ on Silver Electrode in Ethanol Aqueous Solution and Its Determination Using Differential Pulse Voltammetry

摘要

The electrochemistry reduction of coenzyme Q _( 10 ) (CoQ _( 10 ) ) on silver electrodes has been investigated in mixed solvent containing 95 vol. % ethanol and 5 vol. % water. A combination of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) is employed to explore the mechanism of redox processes of CoQ _( 10 ) in the presence and absence of oxygen, respectively. It has been proved that the redox reaction of CoQ _( 10 ) is highly dependent on the oxygen in the solution compared with that of CoQ _( 0 ) , which may be attributed to the isoprenoid side chain effect of CoQ _( 10 ) . Moreover, the effects of experimental variables such as electrolyte component, pH, temperature, and sonication time on the amperometric and potentiometric responses of CoQ _( 10 ) are presented. The differential pulse voltammetry method has been developed for the quantification of the CoQ _( 10 ) in the complex samples. Under the optimum conditions, the method is linear over the concentration range of 1.00 × 10 ~( ?7 ) to 1.00 × 10 ~( ?3 ) mol/L (8.63 × 10 ~( ?2 ) to 8.63 × 10 ~( 2 ) mg/kg). The limit of detection (3σ/k) is 3.33 × 10 ~( ?8 ) mol/L (2.88 × 10 ~( ?2 ) mg/kg). The recoveries of the spiked samples are between 91% and 108%. The presented method can be applied to the analysis of CoQ _( 10 ) in real samples without any pretreatment.