title: Films coated with molecular imprinted polymers for the selective stir bar sorption extraction of monocrotophos.
abstract: The flexibility and simplicity of stir bar sorption extraction (SBSE) have been combined with the selectivity of molecularly imprinted polymers (MIP). Stir bars were coated reproducible with a 180 microm film formed from a formic acid solution of nylon-6 polymer either nonimprinted or imprinted with monocrotophos. Time sorption profiles were measured for the extraction of monocrotophos from dichloromethane at the concentration of 10-200 micromol/L levels with both types of films in order to compare extraction characteristics. The results indicated that the MIP coated layer showed remarkable high affinity toward monocrotophos and equilibrium adsorption was attained rapidly (60 min) in contrast to free standing molecularly imprinted polymer in which equilibrium adsorption was normally attained after several hours. The stir bars coated with MIP films were capable of extracting four structural analogues of monocrotophos from dichloromethane solution, which suggests that both the amino group and PO part of these molecules is responsible for interaction with the imprinted polymer. Evidence was also presented by FT-IR analysis that the amide-hydrogen-bonding interaction between the MIP-coated films and monocrotophos was originated for monocrotophos recognition. To achieve selective extraction of monocrotophos from sample, stir bars coated with MIP films were washed with 10% (v/v) acetic acid/methanol and methanol. Clean extracts and yields of 95% were obtained, demonstrating the suitability of stir bar coated with MIP films for the analysis of environmental and biological samples. Compared with traditional MIP and SBSE, the MIP-coated film showed not only the high selectivity but also the rapid equilibrium adsorption.
authors.affiliation: Department of Chemistry, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Xiaolan
authors.initials: X
authors.lastname: Zhu
authors.forename: Jibao
authors.initials: J
authors.lastname: Cai
authors.forename: Jun
authors.initials: J
authors.lastname: Yang
authors.forename: Qingde
authors.initials: Q
authors.lastname: Su
authors.forename: Yun
authors.initials: Y
authors.lastname: Gao
mesh_terms: D002209:Caprolactam / Q000031:analogs & derivatives / Q000737:chemistry; D002849:Chromatography, Gas / Q000379:methods; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D008855:Microscopy, Electron, Scanning; D015394:Molecular Structure; D008999:Monocrotophos / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification*; D009943:Organophosphorus Compounds / Q000032:analysis; D010575:Pesticides / Q000032:analysis; D011108:Polymers / Q000737:chemistry*; D015203:Reproducibility of Results
chemical_list: D009943:Organophosphorus Compounds; D010575:Pesticides; D011108:Polymers; C009916:nylon 6; D002209:Caprolactam; D008999:Monocrotophos