(166ai) Colorimetric Response of Borohydride Stabilized Silver Nanoparticle on Interaction with Organophosphates

Detection of residual organophosphates in food is of paramount importance in the current scenario. Biosensors for pesticide detection may be developed by monitoring the interaction of nanoparticles with pesticides. In this report, we have studied the colorimetric response of pesticides phorate, chlorpyrifos, and malathion with borohydride stabilized silver nanoparticle. The colorimetric changes are corroborated with UV-Visible spectra along with the change in particle size and zeta potential. The decolorization of phorate with nanoparticles was explained. The reaction mechanism was proposed by the formation of silver and sulfur atom (Ag→S) complex, which is verified by Raman spectroscopy data of the systems. The uncapped nanoparticles get stabilized by pesticides over time for chlorpyrifos and malathion while phorate undergoes degradation due to scission of S-CH₂ present in the molecule. The color change may be utilized as a colorimetric method for the detection of phorate pesticide.