双模板分子印迹材料固相萃取-高效液相色谱法联用测定果蔬中三嗪类农药

Determination of Triazine Residues in Fruits and Vegetables by Dual-Template Molecularly Imprinted Solid Phase Extraction Combined with High Performance Liquid Chromatography

采用灭蝇胺和三聚氰胺为双模板分子,制备对多种三嗪类农药高效吸附的新型分子印迹聚合物材料,并评价其对果蔬中三嗪类杀虫剂残留的吸附性能。经过优化其制备工艺,当灭蝇胺分子和三聚氰胺分子物质的量之比为3∶2时,其吸附量最大。对该聚合物结构进行表征与吸附性能评价,结果表明其最大吸附量分别为2.85 mg/g和5.46 mg/g,结合常数分别为26.688 mg/L和80.775 mg/L,并且其吸附能力在100 min后基本达平衡状态,且呈现比非印迹聚合物更高的吸附量。联用双模版分子印迹聚合物固相萃取-高效液相色谱法以分析黄瓜、苹果和玉米中阿特拉津、扑草净、莠灭净、西草净等三嗪类农药,在加标质量浓度为0.1~0.5μg/mL时,该方法检出限为0.01~0.03 ng/mL,平均回收率为83.2%~102.3%(n=3),相对标准偏差为2.3%~6.8%,适于含有痕量三嗪类农药果蔬样品的检测。

A new dual-template molecularly imprinted polymer(MIPs)for efficient adsorption of triazines was prepared with cyromazine and melamine as template molecules,and its adsorption performance was evaluated for triazine residues in fruits and vegetables.Under the optimized condition of molar ratio of cyromazine to melamine=3:2,the highest adsorption capacity of MIPs was achieved.The maximum adsorption capacity of MIPs at two specific binding sites 2.85 and 5.46 mg/g,and the binding constants were 26.688 and 80.775 mg/L,respectively.The adsorption process attained equilibrium in 100 minutes and showed a higher adsorption capacity than did non-imprinted polymers(NIPs).Molecular imprinting-based solid-phase extraction(MI-SPE)combined with high performance liquid chromatography(HPLC)was used for the measurement of four triazine residues including atrazine,prometryn,ametryn,and simetryn in cucumber,apple,and corn.The limit of detection of this method was 0.01–0.03 ng/mL,and the average recoveries of spiked samples at concentrations ranging from 0.1 to 0.5μg/mL were 83.2%–102.3%(n=3),with relative standard deviation(RSD)between 2.3%and 6.8%.The proposed method,therefore,is suitable for the trace detection of triazine residues in fruit and vegetable samples.