微波辅助-液液微提取环境水样中的三嗪类除草剂

采用微波辅助-液液微提取高效液相色谱法测定环境水样中的三嗪类除草剂.优化了提取溶剂的种类和体积、样品溶液的pH值、盐的浓度、提取时间、微波功率、振荡时间和离心速度等实验条件.在20 mL水样中,加入200 μL 1-己基-3-甲基咪唑六氟磷酸盐(提取剂),控制NaCl的含量为3%(m/V),在300 W时常压微波提取加热1 min,振荡15 min. 提取完成后,在冰水浴中冷却20 min后, 以8000 r/min离心5 min.在最佳实验条件下,5种除草剂在2.5～60 μg/L范围内线性良好,相关系数在0.9972～0.9991之间; 检出限为0.56～1.44 μg/L.     

衍生气相色谱-质谱法测定水中氯代酸性除草剂

采用H2SO4加入法改变了酸性除草剂在水中的存在状态,对碱性活化点的存在与消除进行了分析,同时对不同试剂的萃取效率进行了对比,建立了衍生气相色谱-质谱法测定水中10种氯代酸性除草剂的方法。化合物检出限均低于10.0 ng/L,回收率范围为60%～120%。     

Novel liquid-liquid-solid microextraction method with molecularly imprinted polymer-coated stainless steel fiber for aqueous sample pretreatment

A novel liquid-liquid-solid microextraction (LLSME) method was developed to overcome the well-known water-compatibility problem of molecularly imprinted polymers (MIPs). The enrichment factors with MIP-LLSME method were within 70-210 for trace chloroacetanilide herbicides under optimized extraction conditions. The method was characterized by simplicity, low solvent-consumption and high selectivity, and it was suitable for the one-step pretreatment of various aqueous samples such as river water and farm water.     

New oxacalix[4]arene carboxylate detects viologen in protic media

ABSTRACT

We demonstrate that Ullman fragment-coupling can be used to synthesise an oxacalix[4]arene monocarboxylic acid, which provides easy access to its water-soluble carboxylato derivatives. Crystallographic and computational data suggest that the new carboxyl-substituted oxacalix[4]arene adopts a 1,3-alternate conformation both in the solid-state and in methanol solution. Its water-soluble tetrabutylammonium derivate can detect the herbicide paraquat at neutral pH in aqueous media (K _a = 111 ± 3 M^–1) and in methanol (K _a = 2020 ± 70 M^–1).     

Phenoxy herbicidal ammonium ionic liquids

Ammonium ionic liquids with the 4-chloro-2-methylphenoxyacetate anion were synthesized and characterized. Physicochemical properties, such as thermal stability, phase transition temperatures, viscosity, density, refractive index, as well as surface activity and herbicidal activity were determined. Improved physicochemical properties suggest a reduced environmental impact of newly formed group of herbicidal ionic liquids (HILs). HILs with a longer substituent can be characterized with better herbicidal activity in comparison with commercial products.     

四唑啉酮除草剂的研究进展

综述了四唑啉酮除草剂的研究进展,讨论了其结构和除草活性之间的构效关系。总结了四唑啉酮化合物的合成、取代基对母体除草活性的影响。参考文献27篇。     

高效液相色谱法同时测定牛肉及其制品中敌草隆、绿麦隆的残留量

介绍了用高效液相色谱同时测定牛肉及其制品中脲类除草剂——敌草隆、绿麦隆残留量的方法。色谱柱为ＳｅｌｅｃｔｏｓｉｌＣ１８柱,流动相为甲醇－水（６０∶４０,Ｖ／Ｖ）,ＵＶ－２４５ｎｍ检测。最小检测量：敌草隆为０．４ｎｇ,绿麦隆为０．５ｎｇ。线性范围均为０．０５～１０ｍｇ／Ｌ。回收率：敌草隆为８７．３４％～８７．６４％,绿麦隆为８８．７８％～９１．９４％。     

气相色谱法测定除草剂吡嘧黄隆

A gas chromatography method for the quantitative analysis of pyrazosulfuron is described. Analytical conditions were as follows:column:OV-225 (5% )on Chromosorb W AW DMCS(60-80 mesh),2m column with 3mm i.d.at 172℃;FID at 260℃;N2 as carrier gas with flow rate of 30mL/min.     

QuEChERS-液相色谱-串联质谱法测定甜玉米及毛豆中32种磺酰脲类除草剂残留

建立了基于QuEChERS方法的液相色谱-串联质谱同时测定甜玉米及毛豆中32种磺酰脲类除草剂残留的方法。以提取液净化前后蒸发残渣质量及回收率为考察指标,评估了C18、氧化锆包覆硅胶(Z-Sep)/C18混合物、C18键合锆胶(Z-Sep+) 3种分散吸附剂对甜玉米的净化效果,结果Z-Sep/C18吸附剂的净化效果最佳。样品采用乙腈提取、无水硫酸镁及氯化钠盐析、Z-Sep/C18分散固相萃取净化;液相色谱以CSH C18色谱柱梯度洗脱分离,质谱分析采用电喷雾负离子电离、按时间表的多反应监测模式(Scheduled MRM),以基质匹配校准曲线外标法进行定量。32种农药在甜玉米及毛豆中3个添加水平(10、20、100 μg/kg)的回收率为80.0%~108.2%,相对标准偏差为1.2%~13.0%, 32种农药的定量限(S/N≥10)为0.2~5.0 μg/kg。方法简便、灵敏、环保,适用于甜玉米及毛豆中32种磺酰类除草剂残留的定性定量分析。     

分子印迹固相萃取-液相色谱质谱联用对4种磺酰脲类除草剂残留的测定

采用苄嘧磺隆分子印迹固相萃取柱(MISPE)对加标大米中的苄嘧磺隆、甲磺隆、苯磺隆和烟嘧磺隆4种磺酰脲类除草剂进行净化和富集预处理,并采用LC-MS方法进行定量分析.质谱条件为:正离子检测模式(M+H),检测质量范围为m/z 200 ～800 ,毛细管电压3.93 kV,锥孔电压20 V,脱溶剂温度250 ℃,辅助气流速4 L/min.4种磺酰脲类除草剂在0.01 ～0.70 mg·L~(-1)范围内线性良好.回收率为68% ～100%,表明样品液中的烟嘧磺隆、甲磺隆、苯磺隆和苄嘧磺隆能直接被分子印迹固相萃取柱中的印迹位点保留,而杂质几乎不被保留.分子印迹固相萃取柱对磺酰脲类除草剂表现出良好的识别性能.