Trichloroacetic acid assisted synthesis of gold nanoparticles and its application in detection and estimation of pesticide

Abstract

Background: Many analytical methods are available for detection of methyl parathion in water but they are not handy for on-site analysis. An attempt has been made to utilize stable GNP for methyl parathion detection by sensing the peak at 400 nm generated due to the interaction between methyl parathion and GNP. Methods: GNP was produced by reduction of chloroauric acid solution by trichloroacetic acid in alkaline medium in presence of CTAB. Sensor properties of GNP were studied by varying the concentration of methyl parathion in gold sol from 0 to 500 ppm. Results and discussion: GNP stabilized by CTAB showed only one peak at 532 nm and one broad peak near 300 nm was observed for pure methyl parathion. But as soon as methyl parathion was added in the GNP solution, one new peak at 400 nm developed in addition to the other two peaks. More interestingly, a quantitative decrease of the absorbance at 532 nm of GNP and increase of the absorbance at 400 nm, the new peak, were observed when methyl parathion concentration increased from 10 to 500 ppm. Conclusions: The UV-VIS measurement and TEM images confirmed that the surfactant capped GNP can act as a colorimetric sensor for detection and estimation of methyl parathion pesticide present in water in ppm level.