A molybdenum disulfide/nickel ferrite-modified voltammetric sensing platform for ultra-sensitive determination of clenbuterol under the presence of an external magnetic field.

The electrochemical behavior and sensing performance of an electrode modified with NiFe2O4 (NFO), MoS2, and MoS2-NFO were thoroughly investigated using CV, EIS, DPV, and CA measurements, respectively. MoS2-NFO/SPE provided a higher sensing performance towards the detection of clenbuterol (CLB) than other proposed electrodes. After optimization of pH and accumulation time, the current response recorded at MoS2-NFO/SPE linearly increased with an increase of CLB concentration in the range from 1 to 50 µM, corresponding to a LOD of 0.471 µM. In the presence of an external magnetic field, there were positive impacts not only on mass transfer, ionic/charge diffusion, and absorption capacity but also on the electrocatalytic ability for redox reactions of CLB. As a result, the linear range was widened to 0.5-50 µM and the LOD value was about 0.161 µM. Furthermore, stability, repeatability, and selectivity were assessed, emphasizing their high practical applicability.

Advances in magnetic field-assisted electrolyte's physicochemical properties and electrokinetic parameters: A case study on the response ability of chloramphenicol on Fe3O4@carbon spheres-based electrochemical nanosensor.

Despite the utilization of external magnetic field (MF) in promoting the intrinsic unique features of magnetic nanomaterials in many different applications has been reported, however the origin of MF-dependent electrochemical behaviors as well as the electrochemical response of analytes at the electrode in sensor applications is still not clear. In this report, the influence of MF on the electrolyte's physicochemical properties (polarization, mass transport, charge/electron transfer) and electrode's properties (conductivity, morphology, surface area, interaction, adsorption capability, electrocatalytic ability) was thoroughly investigated. Herein, the working electrode surface was modified with carbon spheres (CSs), magnetic nanoparticles (Fe3O4NPs), and their nanocomposites (Fe3O4@CSs), respectively. Then, they were directly used to enhance the electrochemical characteristics and response-ability of chloramphenicol (CAP). More interestingly, a series of various kinetic parameters related to the diffusion-controlled process of K3[Fe(CN)6]/K4[Fe(CN)6)] and the adsorption-controlled process of CAP were calculated at the bare electrode and the modified electrodes with and without the presence of MF. These parameters not only exhibit the crucial role of the modification of electrode surface with the proposed materials but also show positive impacts of the presence of external MF. Besides, the mechanism and hypothesis for the enhancements were proposed and discussed in detail, further demonstrating the development potential of using Fe3O4@CS nanocomposites with MF assistant for advanced energy, environmental, and sensor related-applications.