An electroanalytical method for determining the concentration of ZnO nanoparticles (< 50 nm) in aqueous dispersion has been developed. The nanoparticles are first allowed to coat a screen-printed electrode by air-drying, which provides a significant magnification of the reduction current for KCl electrolyte at negative potentials. Phenol is next added as a chemical probe for electrochemical analysis by cyclic voltammetry. Measurement of the reduction current at an applied potential of − 0.3 V provides adequate sensitivity for the indirect quantification of ZnO nanoparticles down to a low concentration of 0.1 mg/mL. Other nanoparticles such as TiO2 and CeO2 do not produce any similar reduction peak. Furthermore, the irreversible oxidation peak at + 0.6 V and the charge storage capacity are both linearly proportional to ZnO concentrations (below 0.2 mg/mL) and can afford a detection limit of 0.01 mg/mL nanoparticles. Hence, the new method comprising three simultaneous measurements is good for both the identification and quantification of ZnO nanoparticles.

Coating, Cyclic voltammetry, Electrochemical detection, Environmental effects, Phenol, Water contamination analysis, Zinc oxide nanoparticles
Journal of Nanoparticle Research
Department of Chemistry

Zhang, W. (Wenyu), & Lai, E.P.C. (2020). Electrochemical detection of zinc oxide nanoparticles in water contamination analysis based on surface catalytic reactivity. Journal of Nanoparticle Research, 22(5). doi:10.1007/s11051-020-04823-9