Construction of a molecularly imprinted electroluminescence sensor for pyrimethanil detection via dummy template imprinting combined with click-chemical labeling of mimic enzymes

Background Molecularly imprinted polymer (MIP) sensors have been used to detect trace amounts of pesticide residues. But the difficulty of inert analytes in producing measurable signals often limits the application of MIP sensors. The inherent limitations of the signal transduction mechanism impose fundamental constraints on the enhancement of detection sensitivity. Results Herein, a strategy was proposed for sensitive, selective and rapid determination of trace pyrimethanil (PMT) residues using MIP sensors by the aid of dummy template imprinting. MIP film was synthesized using vinyl pyrimethanil (Abbr. PMT-Vi), a structural analogue of PMT, as the dummy template molecule. After the formation of MIP film, analyte PMT was added for competing with PMT-Vi in the imprinted cavities of MIP. Then, Fe/N-PAMAM-SH, a dendritic polymer bound with Fe/N CDs, was immobilized onto the MIP via the Thiol-ene click reaction between Fe/N-PAMAM-SH and PMT-Vi. PMT was indirectly determined by measuring the ECL signal of Fe/N CDs in the luminol-hydrogen peroxide system. Significance The strategy greatly enhances the detection sensitivity of MIP sensors, achieving a detection limit of 2.58 × 10 -16 mol/L. It also offers a novel approach for detecting molecules that lack characteristic signals or generate weak signals.