Recognition and nanocatalytic amplification of binary MXene carbon dot surface molecularly imprinted nanoprobe for determination of thiamethoxam by molecular spectroscopy

In this experiment, using MXene quantum dot (MQD) as the core and thiamethoxam (TMX) as the template, a dual-functional surface molecularly imprinted polymer nanoprobe (MQD@MIP) for detecting of TMX was synthesized by microwave digestion procedure. And MQD@MIP was characterized in detail. It was found that this nanoprobe had dual function, which not only could specifically recognize TMX, but also could strongly catalyze the new indicator reaction of HAuCl4-maleic acid to produce gold nanoparticles (AuNPs). The AuNPs exhibit strong surface enhanced Raman scattering (SERS), resonance Rayleigh scattering (RRS) and surface plasmon resonance absorption (Abs) effect. Based on this, a new SERS/RRS/Abs trimode biosensoring platform was constructed for the determination of TMX, with a linear range of 1.0–150, 1.0–150, and 5.0–125 nmol/L TMX, and detection limit of 0.57 nmo/L, 0.84 nmol/L and 3.5 nmol/L, respectively. As a comparison, we used carbon dots (CDs) as the core to prepare surface molecularly imprinted polymers (CD@MIP) nanoprobe, and investigated the catalytic effect on the nanogold indicator reaction and the specific recognition effect on TMX.