Structure and physiochemical properties based interaction patterns of organophosphorous pesticides with quantum dots: Experimental and theoretical studies

Abstract

In this study, structure and property interplay mechanism was taken to address the interaction pattern of common organophosphorous (OPs) pesticides with quantum dots (QDs). The thioglycolicacid (TGA) capped CdTe quantum dots (QDs) were synthesized and characterized by prominent methods. The inimitable interaction patterns of organophosphorous (OPs) pesticides with TGA capped CdTe QDs were studied by the quantum chemical method and compared with experimental results (infrared bonding pattern, HR-TEM analysis, photoluminescence quenching, zeta potential variation). The high coordination ability of TGA capped CdTe QDs with malathion among the chosen pesticides (methyl parathion, triethylphosphate and dimethyl methyl phosphonate) was interpreted using frontier molecular orbital theory. The electron transfer rate (Ket) between QDs and malathion was calculated as 2.063 × 108 s−1 from fluorescent life time measurement. The PL quenching spectra of QDs that correspond to the concentration of malathion was evaluated with Stern-Volmer equation and regression analysis. The limit of detection (LOD) and limit of quantification (LOQ) was calculated as 0.68 nM and 2.26 nM respectively from PL quenching spectra. These results were considered as an arsenal tool to deliberate selective sensing approach among the pool of OPs pesticides that have the same mechanism of interaction with acetylcholine enzyme inhibition.