Two-dimensional layered molybdenum disulfide (MoS2)-reduced graphene oxide (rGO) heterostructures modified with Fe3O4 for electrochemical sensing of epinephrine

An epinephrine (also known as adrenaline) molecule plays an important role in neurotransmission. Human body is very sensitive to the change in its concentration and its alteration results, many neurological disorders including Parkinson's and Alzheimer's disease. Hence, the sensitivity and selectivity detection of epinephrine is a significant area of study for the diagnosis of diseases due to their abnormal level in body. The sensing of epinephrine has been carried out at biological pH. In the present work, reduced graphene oxide (rGO)-molybdenum disulfide (MoS2) decorated Fe3O4 (rGO-MoS2@Fe3O4) nanocomposite was synthesized using microwave-assisted method for the electrochemical detection of epinephrine. The as-synthesized rGO-MoS2@Fe3O4 nanocomposite material was characterized to study the morphological and structural analysis by using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), and Raman spectroscopy techniques. In comparison to the bare glassy carbon electrode, rGO-MoS2@Fe3O4 nanocomposite exhibited superior electrocatalytic activity by decreasing the peak potential from 0.3 to 0.2 V and increasing the peak current from 26 μA to 42 μA (61% higher). Compared with reported literature, the rGO-MoS2@Fe3O4 nanocomposite was found to show a lower limit of detection of 1.37 μM and good sensitivity of 2.87 μAμM−1cm−2. Thus, from these results, it is concluded that the as-synthesized rGO-MoS2@Fe3O4 nanocomposite shows improved electrocatalytic properties.