High recycling Fe3O4-CdTe nanocomposites for the detection of organophosphorothioate pesticide chlorpyrifos

Abstract

To alleviate the secondary contamination of our environment when using quantum dots (QDs) to detect the organophosphorothioate pesticides (OPPs), we herein report a strategy to assemble magnetic Fe3O4 nanoparticles and luminescent CdTe quantum dots (QDs) into a composite nanosystem, which possesses both the magnetic property of Fe3O4 nanoparticles and the luminescent character of CdTe QDs, for the detection of chlorpyrifos, one of the typical OPPs. This strategy involves the isolated synthesis of magnetic Fe3O4 nanoparticles with positive charges and luminescent CdTe QDs with negative charges, and their subsequent assembly by electrostatic interaction. The as-prepared Fe3O4–CdTe nanocomposites have a detection limit as low as 10 ppb for chlorpyrifos, and are also selective for the OPPs with a phosphorothioate moiety (PS bond). In specific, the Fe3O4–CdTe nanocomposites can be conveniently harvested by a normal magnet, and the recycling rate for both Cd and Fe determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES) is higher than 96%, showing great potential in alleviating the Cd pollution on the environment.