A Novel Upconversion Fluorescent Sensor Based On Molecularly Imprinted Polymer For Patulin Detection

Patulin [4-hydroxy-4H-furo[3,2-c]pyran-2(6H)-one] is a naturally occurring toxic and carcinogenic secondary metabolite produced by a variety of species. It has a broad spectrum of toxicity also against plants, protozoa and animals. For human beings, patulin has caused nausea, vomiting and gastrointestinal disturbances. Patulin has been found mainly in apples and its products, and occasionally in other fruits. Thus, it is necessary to establish a high selective method for patulin detection.We proposed a novel upconversion fluorescent sensor based on molecularly imprinted polymers for highly selective and sensitive recognition of patulin. Firstly, we prepared a oil-soluble hexagonal phase β-NaYF4 Yb3+, Er3+ and modifyed it into water-soluble by Triton X-100, then synthesized a kind of new support vector UCNPs@SiO2 by classic Stober Alkaline hydro lysis, which can also be used as signal output materal. Since patulin is expensive and highly toxic, HMF which is patulin analogue was chosen as the template. UCNPs@MIPs was synthesized via a sol-gel polymerization process with APTES as functional monomer, TEOS as cross-linker and UCNPs@SiO2 as support vector. The prepared oil-soluble UCNPs, water-soluble UCNPs, UCNPs@SiO2 and UCNPs@MIPs was characterized by FT-IR, SEM, TEM, XRD, fluorescence spectrophotometer and adsorption experiment.The results showed that after binding patulin, the fluorescence intensity of UCNPs@MIPs quenched. Under optimal conditions, the relative fluorescence intensity of UCNPs@MIPs decreased linearly with the increasing concentration of patulin in the range of 0.05-0.8 mg L-1 with a detection limit of 0.04 mg L-1.To evaluate the usefulness of the new developed method, UCNPs@MIPs was applied to detect patulin in apple juice, pear juice, and haw flakes, and at three concentration levels (100,200 and 400μg kg-1), the recoveries for three samples were 87.4%-95.3.0%(RSD <4.6%)、 84.5%-87.7%(RSD< 2.5%)、 76.3%-83.2%(RSD< 6.7%).respectively. It proves that the developed method based on UCNPs@MIPs for detection of patulin in cereals is feasible. Furthermore, to verify the validity of the developed method, liquid chromatography-SPD detection was used to detect patulin recoveries of above samples. The results were 84.3%-89.0%(RSD< 4.8%),80.7%-88.1% (RSD< 3.8%).67.7%-82.9% (RSD< 7.2%)...