Single-laser fabrication of nitrogen-doped porous graphene from chitosan/polyimide for the electrochemical determination of dextromethorphan.

A simple and effective disposable electrode was developed for the electrochemical detection of dextromethorphan (DEX) in pharmaceutical and forensic samples. Polyimide was treated with chitosan before being used to create the electrode through single-laser fabrication of nitrogen-doped porous graphene. The laser power and speed were optimized to achieve optimal performance. Scanning electron microscopy, energy dispersive X-ray, Raman and Fourier transform infrared spectroscopy were used to characterize the morphology of fabricated materials. The electrochemical characterization of electrodes was studied by using cyclic voltammetry and electrochemical impedance spectroscopy. The electrochemical behavior of DEX was investigated using cyclic voltammetry and analytical measurements were performed using differential pulse voltammetry. Differential pulse voltammetry was optimized in terms of buffer type, buffer pH, potential pulse, time pulse, potential step, scan rate, deposition potential, and deposition time. In the optimal condition, two linear ranges were observed, ranging from 2.5 to 25 μmol L and 25 to 400 μmol L. The limit of detection (LOD) was 1.8 μmol L. The developed method produced a statistically significant agreement with high-performance liquid chromatography for the determination of DEX.