Ketamine plasmonic sensor using polyaniline-rGO-Fe3O4 nanocomposite thin layer

Ketamine is a narcotic and palliative substance and the measurement of the low concentration of ketamine is a great intense interest matter in biotechnology and medicine. The surface plasmon resonance imaging method can monitor the low concentration of bio-substance such as ketamine and dopamine. The reduced graphene oxide-Fe3O4 nanoparticles and polyaniline-reduced graphene oxide-Fe3O4 nanocomposite layers as the sensing layer were prepared using sonication and electro-deposition methods, respectively. The average particle size of Fe3O4 was 38.53 nm, and the sensing layer thickness was in the range of 19-24.5 nm. The morphology, functional group, and contribution of chemical elements were investigated using field emission electron microscopy; Fourier transforms infrared spectroscopy, and energy-dispersive X-ray spectroscopy, respectively. The surface plasmon resonance imaging pattern confirmed that the minimum concentration for detecting ketamine, the sensitivity of the sensor, and the response time were about 0.1 mg/L, 0.044, and 220 s, respectively. The affinity constant is 11.19 for the detection of ketamine, and the tendency of the sensing layer to bind the ketamine is higher than dopamine and glucose.