Fluorescent and colorimetric dual-response sensor based on copper (II)-decorated graphitic carbon nitride nanosheets for detection of toxic organophosphorus.

An efficient and convenient detection method for organophosphorus pesticide (OP) residues is needed because of their high neurotoxicity and severe threat to food safety. OPs effectively reduce the production of thiocholine in the acetylcholinesterase/acetylthiocholine reaction by inhibiting the activity of acetylcholinesterase. Therefore, we developed a feasible and convenient fluorescent and colorimetric dual-response sensor based on the competitive complexation of Cu2+ between graphitic carbon nitride nanosheets and thiocholine for the rapid detection of OPs with high sensitivity. Malathion was used as a model OP, and a linear range of 70-800 nM with a detection limit of 6.798 nM for a fluorescent signaling platform and 2.5-25 nM with a detection limit of 1.204 nM for a colorimetric probe were attained. The constructed probe was successfully applied to determine OP in actual samples of cabbages leaves and tap water. The results indicated that the dual-response probe was reliable and sensitive to actual samples.