莠去津磁性分子印迹材料的制备及在蔬菜检测中的应用

Determination of atrazine in vegetables by magnetic molecularly imprinted polymer flow injection preconcentration and gas chromatography

目的建立基于流动注射系统磁性分子印迹技术联用气相色谱法快速测定蔬菜中莠去津的检测方法。方法磁性分子印迹材料以壳聚糖包裹的四氧化三铁(Fe_3O_4-CS)为载体,莠去津为模板分子,甲基丙烯酸为功能单体,二甲基丙烯酸乙二醇酯为交联剂制备所得。蔬菜样品经乙酸乙酯提取,自制磁性分子印迹固相萃取柱净化富集,用甲醇洗脱目标化合物随后进入气相色谱仪进行定量测定。结果通过静态吸附实验考察磁性分子印迹材料对莠去津的最大吸附容量为52.0 mg/g。在本实验条件下,莠去津在5～100μg/L范围内线性良好,相关系数(R^2)0.9976,样品加标时,方法回收率为81.5%～107.7%(n=6),检出限为0.6μg/kg。结论本方法净化效果较好,可以用于蔬菜样品中莠去津残留检测。

OBJECTIVE A method for rapid determination of atrazine in vegetables by gas chromatography based on magnetic molecular imprinting technology in flow injection system was established.METHODS Core-shell magnetic molecularly imprinted polymers were prepared using ferroferric oxide modified with chitosan as the carrier,atrazine as the template,methacrylic acid as the functional monomer,and ethylene glycol dimethacrylate as the cross-linker.The attraction of the imprinted polymers for atrazine was studied through static equilibrium binding.The atrazine in the sample were extracted with ethyl acetate and then cleaned-up with MIPs SPE cartridges.The target molecules were eluted by methanol and then quantitatively determined by gas chromatograph.RESULTS The maximum adsorption capacity was 52.0 mg/g.Under the optimal conditions,the linearity of the method obtained was 5-100μg/L.The detection limits of atrazine was 0.6μg/kg.The recoveries were between 81.5%and 107.7%(n=6).CONCLUSION The proposed method is successfully applied to determine atrazine in vegetables.