Highly selective and responsive detection of simetryn in tobacco samples based on molecularly imprinted photonic crystal hydrogels

A novel sensor was developed based on the combination of photonic crystal templating and molecular imprinting technique (MIT) for the detection of simetryn in tobacco samples. The molecularly imprinted photonic crystal hydrogels (MIPHs) was prepared with methacrylic acid (MAA) as monomers, ethylene glycol dimethylacrylate (EGDMA) as cross-linkers, simetryn as imprinting template molecules and polystyrene (PS) microspheres as photonic crystal template. The ordered three-dimensional macro-porous structure of MIPHs with simetryn imprinting template can generate Bragg diffraction, showing a bright structural color. The results show that the MIPHs have high selectivity and excellent sensing performance and can be used for the detection of simetryn from actual tobacco samples. Among the four triazine herbicides with similar structure, MIPHs only produced obvious Bragg diffraction peak wavelength change to simetryn, and MIPHs have good recoverability with four cycle times. When the concentration of simetryn in the actual tobacco increased from 0 to 1.0 mu g/mL, the wavelength was red-shifted from 457 nm to 499 nm, which was in the blue and green visible light wavelength range. This new sensor is expected to be used to directly detect pesticide residues in tobacco.