Mn-doped ZnS synthesis in DABCO based ionic liquid: Morphology and electrochemical sensing performance for isoprenaline analysis

ZnS nanostructures with Mn2+ doping (5%) have been prepared in ionic liquid (IL) through the reflux method. The undoped ZnS and Mn2+ doped ZnS (Mn.ZnS) nanostructures produced in the presence and lack of IL, were analyzed using X-ray diffraction, scanning electron microscopy, and Brunauer-Emmett- Teller methods. Then, the surface of the glassy carbon electrode (GCE) was modified by synthesized nano ZnS and Mn.ZnS and electro-activated by successive cyclic voltammetry (CV) in a NaOH solution. The sensing ability of the modified GCEs towards isoprenaline (ISP) was examined by CV and differential pulsed voltammetry (DPV) for which less over potentials with sharper redox currents were resulted compared to the bare GCE. The optimized Mn.ZnS/GCE was stable in buffer solutions in the pH range of 2-8 and exhibited a linear response for ISP concentrations in the range of 0.5-30 mu M with promising sensitivity of 2.1 mA/mM and low detection limit of 90 nM. Adequate selectivity for determining ISP in the presence of other biological compounds such as ascorbic acid, uric acid at pH 5.0 confirmed the potential applicability of Mn.ZnS/GCE for ISP sensing in real biological samples. Finally, an electrochemical mechanism for the catalytic oxidation of ISP was proposed. (c) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.

Automated summary

ZnS nanostructures doped with Mn2+ were prepared in an ionic liquid through the reflux method, followed by modification of a glassy carbon electrode and examination of sensing ability towards isoprenaline. The optimized Mn.ZnS/GCE showed stable performance for isoprenaline detection with promising sensitivity and low detection limit. The study proposed an electrochemical mechanism for the catalytic oxidation of isoprenaline.