Highly sensitive colorimetric detection of organophosphate pesticides using copper catalyzed click chemistry

Highly sensitive colorimetric detection of organophosphate pesticides (OPs) was developed using Cu (I)-catalyzed click chemistry as the colorimetric signal amplification process between the acetylcholine esterase–acetylthiocholine system (AChE–ATCl) and azide- terminal alkyne-functionalized Au NPs as the colorimetric probe. It was demonstrated that the involvement of Cu (I)-catalyzed click chemistry allowed greatly improved colorimetric sensitivity for OPs detection based on the indirect modulation of click chemistry-induced Au NPs aggregation by the AChE–ATCl system. Paraoxon as the model OPs in the concentration range from 10−6 to 10−4 g/L can be directly detected using the naked-eye-based colorimetric assay without the aid of any complex instruments. The results for paraoxon detection in spiked apple juice were found to be in good agreement with that obtained by the conventional UV–vis spectroscopy. This simple and reliable assay would greatly improve the public safety and environmental protection in an on-site and real-time detection format.