表面增强拉曼光谱法对水中残留绿麦隆的检测

利用银镜反应原理在玻璃片上镀一层具有表面增强拉曼散射(SERS)效应的表面粗糙的银膜,通过测定农药绿麦隆在银镜表面上的表面增强拉曼光谱,探讨了绿麦隆在银镜表面的吸附取向。结果表明,在银镜表面,当绿麦隆浓度小到10-10mol L时,仍然能得到明确的光谱信息,且吸附饱和时间仅为2h,这为探索水体中微量污染物的检测方法提供了一个很好的途径。     

基于门控制电催化效应的分子印迹传感器

以绿麦隆为模板分子,在镍电极表面聚合制得绿麦隆分子印迹膜。洗脱后的分子印迹膜重新吸附不同浓度绿麦隆分子,在印迹膜上形成不同量的印迹孔穴,H2O2通过印迹孔穴在镍电极表面产生电催化氧化,从而形成门控制电催化效应,以此对绿麦隆进行定量分析。研究表明,镍电极对H2O2有较好的催化效果,分子印迹聚合膜中模板分子、功能单体和交联剂的摩尔配比为1∶12∶30,重吸附时间为10 min,测试缓冲液pH=7.2。H2O2的催化电流值与绿麦隆浓度在1.0×10-4～4.0×10-7 mol/L范围内呈良好的线性关系;检出限为2.9×10-8 mol/L。将传感器应用于农田水样的检测,其回收率在97%～103%之间。     

GC-ITD analysis of chlortoluron and its metabolites in cereals

Summary Chlortoluron and its metabolites have been determined in cereals by gas chromatography. Chlortoluron is pyrolyzed to the corresponding phenylisocyanate, which is determined by GC with nitrogen-phosphorous detection (NPD) and confirmed by GC with ion trap detection (ITD).N-demethyl metabolites of chlortoluron are determined, after conversion to the perfluoroacyl derivatives, by GC with ion trap detection by single ion monitoring;N-ethyl-p-chloroacetanilide is used as internal standard. The hydroxymethyl metabolite, mainly present as -glucoside, can be analyzed, after enzymatic hydrolysis with -glucosidase and conversion to the ethyl derivative, by GC with ion trap detection by SIM;N-ethylchlortoluron is used as internal standard.The methods proposed are reproducible and sensitive enough for determination of these compounds at residue levels in cereals.     

A Sensitive and Renewable Chlortoluron Molecularly Imprinted Polymer Sensor Based on the Gate‐Controlled Catalytic Electrooxidation of H2O2 on Magnetic Nano‐NiO

A new sensor was fabricated by MIP synthesized on the surface of magnetic nickel(II) oxide (NiO) nanoparticles which based on the oxidation current change of H₂O₂. Chlortoluron was selected as template which can be detected indirectly by the decrease of the H₂O₂ oxidation current on the NiO nanoparticle‐modified GCE caused by the blocking access after rebinding. A high sensitivity was obtained because of the high catalytic effect of NiO nanoparticles on H₂O₂ oxidation. Chlortoluron was determined from 1.0×10^?8/L to 1.0×10^?4 mol/L, with a detection limit of 2.4×10^?9 mol/L. The proposed method combines the high sensitivity of the catalytic effect and the high selectivity of the MIP technique. Water samples were assayed using the MIP sensor, and recoveries of 96.9 % to 104.7 % were obtained.