Preparation And Application Of A Molecularly Imprinted Material Of Ctrinin

Citrinin is a toxic metabolite produced by several filamentous fungi such as Penicillium, Aspergillus and Monascus. It has been encountered as a natural contaminant in grains, foods, feedstuffs, as well as biological fluids. Researchers have recognized its dangers and established a series of research approaches including thin-layer chromatogram-phy, high performance liquid chromatography, enzyme-linked immunosorbent assay, liquid chromatography mass spectrometry, gas chromatography mass spectrometry, etc. However, these relative limited analytical datas were based on diverse analytical methods with differrent sensitivity and accuracy. It was difficult to establish widely acceptable limit for citrinin. Presently, there is no specific legislation for citrinin worldwide. In order to protect public health and promote international trade, more sensitive and accurate analytical methods for citrinin should be developed, and international criteria should be established for the quality control of products contaminated with citrinin.In this paper, by combining surface molecular imprinting technique with1,4-naphthalene dicarboxylic acid was used as template, silica gel as support material,3-aminopropyltriethoxysilane as functional monomer, and tetraethoxysilicane as cross-linker, a novel basic citrinin molecularly imprinted polymer with good selectivity and sensitivity was prepared. A series of optimization experiments were carried out to determine the optimum synthesis conditions, including the ratios, the amount of silica beads, catalyst and so on. And then this imprinted polymer was evaluated through static adsorption test, kinetic adsorption test, selective adsorption test and infrared spectroscopy experiments. The results obtained indicated that the imprinted polymer exhibited high selective ability, good adsorption capacity and fast binding kinetics for citrinin.The polymer was packed as’the sorbent of the solid-phase extraction, and used it to enrich the citrinin exisit in food samples, after that it was detected on the HPLC-FLD. Experiments on the sample solution, sample flow rate, eluent composition, elution volume and other conditions were optimized to determine the optimal conditions for solid-phase extraction. Under the optimum conditions, the detection limit (S/N=3) was37.46ng L-1.The linear plots with R2=0.999were achieved over a range of0.5-50μg L-1and the peak area precision (RSD) for nine parallel determinations was below6.655%.In order to evaluate the applicability of the method, rice, maize and vinegar which were determined to be free of citrinin, were spiked with three levels of citrinin (50μg kg-1、100μg kg-1、250μg kg-1) and analyzed after simple pretreatment. And then, the citrinin was detected by the established method, the result showed that the recoveries were ranging from77.8%to95.8%, and thus proving that the established analytical method had good practicability for citrinin.