Wu Mao, Fan Yajun, Li Jiawei, Lu Danqing, Guo Yaping, Xie Lianwu, Wu Yiqiang
College of Sciences, Central South University of Forestry and Technology, Changsha 410004, China.
College of Material Science and Technology, Central South University of Forestry and Technology, Changsha 410004, China.
Polymers (Basel). 2019 Oct 27;11(11):1770. doi: 10.3390/polym11111770.
The rapid detection of organophosphorus pesticide residues in food is crucial to food safety. One type of novel, magnetic, molecularly-imprinted polymeric microsphere (MMIP) was prepared with vinyl phosphate and 1-octadecene as a collection of dual functional monomers, which were screened by Gaussian09W molecular simulation. MMIPs were used to enrich organic phosphorus, which then detected by fluorescence quenching in vinyl phosphate-modified carbon dots (CDs@VPA) originated from anhydrous citric acid. MMIPs and CDs@VPA were characterized by TEM, particle size analysis, FT-IR, VSM, XPS, adsorption experiments, and fluorescence spectrophotometry in turn. Through the fitting data from experiment and Gaussian quantum chemical calculations, the molecular recognition properties and the mechanism of fluorescence detection between organophosphorus pesticides and CDs@VPA were also investigated. The results indicated that the MMIPs could specifically recognize and enrich triazophos with the saturated adsorption capacity 0.226 mmol g, the imprinting factor 4.59, and the limit of recognition as low as 0.0006 mmol L. Under optimal conditions, the CDs@VPA sensor has shown an extensive fluorescence property with a LOD of 0.0015 mmol L and the linear range from 0.0035 mmol L to 0.20 mmol L (R = 0.9988) at 390 nm. The mechanism of fluorescence detection of organic phosphorus with CDs@VPA sensor might be attributable to hydrogen bonds formed between heteroatom O, N, S, or P, and the O-H group, which led to fluorescent quenching. Meanwhile, HN-C=O and Si-O groups in CDs@VPA system might contribute to cause excellent blue photoluminescence. The fluorescence sensor was thorough successfully employed to the detection of triazophos in cucumber samples, illustrating its tremendous value towards food sample analysis in complex matrix.
食品中有机磷农药残留的快速检测对食品安全至关重要。以磷酸乙烯酯和1-十八烯为双功能单体组合，通过Gaussian09W分子模拟筛选，制备了一种新型磁性分子印迹聚合物微球（MMIP）。MMIP用于富集有机磷，然后通过源自无水柠檬酸的磷酸乙烯酯修饰的碳点（CDs@VPA）中的荧光猝灭进行检测。依次通过透射电子显微镜（TEM）、粒度分析、傅里叶变换红外光谱（FT-IR）、振动样品磁强计（VSM）、X射线光电子能谱（XPS）、吸附实验和荧光分光光度法对MMIP和CDs@VPA进行表征。通过实验数据与高斯量子化学计算的拟合，还研究了有机磷农药与CDs@VPA之间的分子识别特性和荧光检测机理。结果表明，MMIP对三唑磷具有特异性识别和富集能力，饱和吸附容量为0.226 mmol/g，印迹因子为4.59，识别限低至0.0006 mmol/L。在最佳条件下，CDs@VPA传感器表现出广泛的荧光特性，在390 nm处的检测限为0.0015 mmol/L，线性范围为0.0035 mmol/L至0.20 mmol/L（R = 0.9988）。CDs@VPA传感器对有机磷进行荧光检测的机理可能归因于杂原子O、N、S或P与O-H基团之间形成的氢键，从而导致荧光猝灭。同时，CDs@VPA体系中的HN-C=O和Si-O基团可能有助于产生优异的蓝光光致发光。该荧光传感器已成功应用于黄瓜样品中三唑磷的检测，表明其在复杂基质食品样品分析中具有巨大价值。
