title: Evaluation of a novel microextraction technique for aqueous samples: porous membrane envelope filled with multiwalled carbon nanotubes coated with molecularly imprinted polymer.
abstract: A novel microextraction technique based on membrane-protected multiwalled carbon nanotubes coated with molecularly imprinted polymer (MWCNTs-MIP) was developed. In this technique, MWCNTs-MIP were packed inside a polypropylene membrane envelope, which was then clamped onto a paper clip. For extraction, the packed membrane envelope was first impregnated with toluene and then placed in sample solutions. Target analytes in the solutions were first extracted into toluene in the membrane envelope, and were then extracted specifically onto the MWCNTs-MIP. After the extraction, target analytes were desorbed in methanol for liquid chromatography analysis. MWCNTs-MIP of prometryn were used as a model to demonstrate the feasibility of this novel microextraction technique. Factors affecting the extraction including organic solvent, stirring rate, extraction time, salt concentration, and pH were investigated. Under the optimized conditions, the limits of detection (a signal-to-noise ratio of 3) for the selected triazine herbicides were 0.08-0.38 μg/L. The prepared membrane envelope could be used at least 50 times. The developed method was used for the analysis of the triazines spiked in river water, wastewater, and liquid milk, with recoveries ranging from 79.3-97.4, 58.9-110.3 and 76.2-104.9%, respectively.
authors.affiliation: Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education, School of Environmental Science and Technology, Dalian University of Technology, Dalian, P. R. China. tanfdl@yahoo.com.cn
authors.forename: Feng
authors.initials: F
authors.lastname: Tan
authors.forename: Minjie
authors.initials: M
authors.lastname: Deng
authors.forename: Xue
authors.initials: X
authors.lastname: Liu
authors.forename: Hongxia
authors.initials: H
authors.lastname: Zhao
authors.forename: Xiaona
authors.initials: X
authors.lastname: Li
authors.forename: Xie
authors.initials: X
authors.lastname: Quan
authors.forename: Jingwen
authors.initials: J
authors.lastname: Chen
mesh_terms: D000327:Adsorption; D002851:Chromatography, High Pressure Liquid; D006540:Herbicides / Q000032:analysis / Q000302:isolation & purification*; D054802:Molecular Imprinting; D037742:Nanotubes, Carbon / Q000737:chemistry*; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D016062:Porosity; D052617:Solid Phase Microextraction / Q000295:instrumentation / Q000379:methods*; D014227:Triazines / Q000032:analysis / Q000302:isolation & purification*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000302:isolation & purification*
chemical_list: D006540:Herbicides; D037742:Nanotubes, Carbon; D011108:Polymers; D014227:Triazines; D014874:Water Pollutants, Chemical