The Construction Of Perovskite Quantum Dots-molecularly Imprinted Fluorescent Sensor And Application In Sudan Ⅰ In Food

Molecularly imprinted polymers are widely used in the field of fluorescent sensing because of their high stability,simple preparation process and strong specificity.In this study,molecularly imprinted polymers with different structures were combined with perovskite quantum dots,a new fluorescent material,to prepare two fluorescent encoding microspheres with different structure compositions.The two fluorescent sensors can be used for the accurate,rapid and sensitive detection of SudanⅠin food.（1）A synthesis method for SudanⅠmolecularly imprinted fluorescent encoding microspheres was established,and a perovskite quantum dot-molecularly imprinted fluorescent sensor was developed for the detection of SudanⅠ.The molecularly imprinted polymers of sudanⅠwas prepared by precipitation using SudanⅠas template,methacrylic acid as functional monomer,ethylene glycol dimethacrylate and divinylbenzene as crosslinking agents,and azodiisobutyronitrile as initiator.The MIPs used as the encoding matrix and three different colors of pervoskite quantum dots were respectively encoded to prepare three different colors of fluorescent encoding microspheres.The optical properties and stability of the fluorescent encoding microspheres were evaluated.One of the coded microspheres was used as a fluorescent sensor for the quantitative detection of SudanⅠ.The linear range of the fluorescent sensor was 0.5-150μg L^-1,limit of detection was 0.3μg L^-1,and the imprinted factor was 3.28.The detection time of SudanⅠby the sensor was 30 min.The recoveries were95.27-105.96%,and the relative standard deviations were less than 6.94%.In addition,this study greatly simplified the process of preparing perovskite quantum dot-molecularly imprinted fluorescent sensors.（2）A synthesis method for SudanⅠhollow molecularly imprinted fluorescent encoding microspheres was established,and a fluorescent sensor for the rapid detection of SudanⅠin food was developed.Firstly,the polymers were prepared by surface imprinting technique using ZIF-8 as the carrier and SudanⅠas the template molecule.Because the structure of ZIF-8 was unstable under acidic conditions,and the structure of ZIF-8 was destroyed during the elution of template.The polymers formed molecularly imprinted polymer with hollow structure.Similarly,hollow structure polymers were used as encoding matrix and three different colors of perovskite quantum dots were directly mixed and encoded to prepare hollow structure fluorescent encoding microspheres.The structure and fluorescence properties of the molecularly imprinted polymers and encoding microspheres were characterized in detail,and compared with solid structure fluorescent encoding microspheres.Finally,one of the encoding microspheres was used as fluorescent sensor to detect SudanⅠ.The linear range of the fluorescence sensor was 0.1-300μg L^-1,the limit of detection was 0.05μg L^-1,and the imprinted factor was 4.80.The recoveries of different samples were 94.91-105.36%,and the relative standard deviations were less than 6.28%.Compared with solid structure fluorescent sensor,the detection time was reduced to 10 min,and the sensitivity was increased by 6 times.The constructed hollow fluorescent sensor provided a fast,sensitive and efficient way for the detection of SudanⅠin food.