Gold nanoparticles modified exfoliated graphite electrode as electrochemical sensor in the determination of psychoactive drug.

The use and abuse of prescription and illicit drugs are on the rise worldwide and as a result residue of these drugs and their metabolites are continually being disposed into the environment through sewage system and other means. Therefore, this paper reports on the development of a cost-effective, simple and sensitive approach that involved the fabrication of an electrochemical sensor from exfoliated graphite (EG) and gold nanoparticles (AuNPs) for the detection of selected psychoactive drugs in water. The fabricated electrochemical sensor was characterized using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS) to ascertain its surface morphology characteristics and cyclic voltammetry (CV) for ascertaining the redox potential peak. The EG-AuNPs sensor was able to detect cocaine in water with limit of detection (LOD) and limit quantification (LOQ) of 0.82 and 2.74 µg/L, respectively under the pH of 12.25. The sensor was extended on other psychoactive drugs (methylphenidate, amphetamine and heroin) and one metabolite (6-acetylmorphine) to examine its applicability. The drugs were distinctively detected, and thus making EG-AuNPs electrode a possible alternative sensor for electrochemical detection of psychoactive drugs and their metabolites in synthetic and real water samples.