An on-site and portable electrochemical sensing platform based on spinel zinc ferrite nanoparticles for the quality control of paracetamol in pharmaceutical samples.

In this study, crystalline spinel zinc ferrite nanoparticles (ZnFe 2 O 4 NPs) were successfully prepared and proposed as a high-performance electrode material for the construction of an electrochemical sensing platform for the detection of paracetamol (PCM). By modifying a screen-printed carbon electrode (SPE) with ZnFe 2 O 4 NPs, the electrochemical characteristics of the ZnFe 2 O 4 /SPE and the electrochemical oxidation of PCM were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), chronoamperometry (CA), and differential pulse voltammetry (DPV) methods. The calculated electrochemical kinetic parameters from these techniques including electrochemically active surface area (ECSA), peak-to-peak separation (Δ E p ), charge transfer resistance ( R ct ), standard heterogeneous electron-transfer rate constants ( k 0 ), electron transfer coefficient ( α ), catalytic rate constant ( k cat ), adsorption capacity ( Γ ), and diffusion coefficient ( D ) proved that the as-synthesized ZnFe 2 O 4 NPs have rapid electron/mass transfer characteristics, intrinsic electrocatalytic activity, and facilitate the adsorption-diffusion of PCM molecules towards the modified electrode surface. As expected, the ZnFe 2 O 4 /SPE offered excellent analytical performance towards sensing of PCM with a detection limit of 0.29 μM, a wide linear range of 0.5-400 μM, and high electrochemical sensitivity of 1.1 μA μM -1 cm -2 . Moreover, the proposed ZnFe 2 O 4 -based electrochemical nanosensor also exhibited good repeatability, high anti-interference ability, and practical feasibility toward PCM sensing in a pharmaceutical tablet. Based on these observations, the designed electrochemical platform not only provides a high-performance nanosensor for the rapid and highly efficient detection of PCM but also opens a new avenue for routine quality control analysis of pharmaceutical formulations.