Sensitive electrochemiluminescence aptasensor for chlorpyrifos detection based on resonance energy transfer between MoS2/CdS nanospheres and Ag/CQDs

A "signal on" aptasensor was fabricated for chlorpyrifos detection by a highly efficient electrochemiluminescence resonance energy transfer (ECL-RET) strategy between MoS 2 /CdS nanospheres and silver/carbon quantum dots (Ag/CQDs). Compared with the conventional MoS 2 /CdS nanosheets, the MoS 2 /CdS nanospheres have a larger specific surface area and electron density, which makes the catalytic effect on K 2 S 2 O 8 stronger and has higher luminescence intensity. As a receptor, through the synergistic effect of Ag NPs and CQDs, it has a very wide absorption band between 300 and 600 nm. The absorption band and the emission spectrum of MoS 2 /CdS completely overlap, and the high quantum yield of Ag/CQDs can achieve efficient energy resonance transfer. The proposed ECL aptasensor provided a linear range from 10 nM to 1.0 fM for chlorpyrifos detection and the detection limit of 0.35 fM (S/N = 3) under optimal experimental conditions. The method was successfully applied to the detection of chlorpyrifos in fruit and vegetable samples with satisfactory results.