Colorimetric Detection of Pesticide Residues in Water Using Zinc oxide Nanoparticles

Abstract

Zinc oxide nanoparticles were synthesized through green chemistry using lemon extract as reducing agent. The sensitivity of the synthesized nanoparticles against pesticide residues in water was determined. The nanoparticles were characterized based on the absorbance. Characteristic peaks were observed at 281 nm and 328 nm attributed to the exciton absorption peak and maximum absorbance that confirmed the size of the product. The nanoparticles were mixed with different concentration of pesticides in water at varying ratio. The color change was observed in relation to its sensitivity to the solutions. Evident change in color from pale yellow to colorless were observed for both 400 ppb of clothianidin and imidacloprid mixed with ZnO nanoparticles at 1:1 ratio. Absorbance spectra revealed that there is a difference in the interaction of the two pesticides with ZnO nanoparticles. However, same visual color change were observed for both pesticides from pale yellow to colorless. This suggests that the ZnO nanoparticles were not selective as colorimetric detector for clothianidin and imidacloprid.