A novel electrochemical aptasensor based on core–shell nanomaterial labeling for simultaneous detection of acetamiprid and malathion

At present, due to the coexistence of multiple pesticides in vegetables and the enhanced toxicity, a simultaneous detection method for multiple pesticides is urgently needed. In this work, two types of core-shell nanomaterials, Ag-Au core-shell nanoparticles (Ag@Au NPs) and Cu2O-Au core-shell nanoparticles (Cu2O@Au NPs), were synthesized and labeled with acetamiprid aptamer and malathion aptamer to prepare two novel electroactive signal probes, respectively. The two probes were hybridized on the surface of the electrode by the principle of base complementary pairing between the aptamers and the thiolated DNA oligonucleotide sequences, and a dual-signal electrochemical aptasensor for the simultaneous detection of acetamiprid and malathion was established by modified glassy carbon electrode (GCE). The limits of detection (LOD) were calculated to be 43.7 pg mL-1 for acetamiprid and 63.4 pg mL-1 for malathion. The aptasensor determined acetamiprid and malathion in spinach and rape with the recovery rates of 88.9%-112.5% and 98.0%-114.1%, respectively.