Defective mesoporous carbon ceramic electrode modified graphene quantum dots as a novel surface-renewable electrode: The application to determination of zolpidem

A novel sensitive electrochemical sensor was developed for detection and determination of zolpidem (Zip) based on graphene quantum dots modified defective mesoporous carbon ceramic electrode (DMCCE-GQDs). The cyclic voltammetry (CV), choronoamperometry (CA), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) techniques were used for electrochemical studies and drug determination. The electrocatalytic currents increased with the Zlp concentration and exhibit two linear dynamic ranges with a detection limit of 0.061 mu M Zlp (S/N = 3). The linear calibration ranges were obtained between 0.1 and 1 and 1-10 mu M Zlp using the DPV method. The diffusion coefficient (D = 4.2 x 10(-5) cm(2) s(-1)) and the heterogeneous rate constant, (k = 7.53 x 10(2) cm s(-1)) for Zlp were determined. Finally, the modified electrode was successfully applied to determination of Zlp in tablet dosage forms with a mean recovery of 97.6%.