Resin bound gold nanocomposites assisted SE/ATR-FTIR spectroscopy for detection of pymetrozine insecticide in vegetable samples.

The goal of this work was to assess the competence of organic hydrophobic resin bound gold nanocomposites (OH/R-AuNCs) for detection of pymetrozine insecticide from vegetable samples employing surface-enhanced/attenuated total reflectance-Fourier transform infrared (SE/ATR-FTIR) spectroscopy. The adsorption isotherm models, including the Langmuir, Freundlich and Temkin, are tested to reveal the interactive behaviour between the OH/R-AuNCs and pesticide. The adsorption occurs principally by London-Van der Waals dispersion interactions and hydrogen bonding interactions between the surface of OH/R-AuNCs materials and the hydrophobic part of pesticide molecule. The characteristic absorption band obtained at 3019.94 cm was utilized for the quantitative analysis of pymetrozine insecticide in vegetable samples. The method was found to be accurate and precise, with mean recovery values in the range of 94.5-110 %, correlation coefficient of 0.992 %, and detection limit of 2.65 μg mL. The adsorption efficiency of the designed OH/R-AuNCs significantly influences the SE/ATR-FTIR response of the pymetrozine around 90 %. The optimized and validated method was applied to determine the residual concentrations of the pymetrozine that had been applied to vegetable samples.