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 x 10(-7) to 1.00 x 10(-3) mol/L (8.63 x 10(-2) to 8.63 x 10(2) mg/kg). The limit of detection (3 sigma/k) is 3.33 x 10(-8) mol/L (2.88 x 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.