title: pH-controlled quaternary ammonium herbicides capture/release by carboxymethyl-β-cyclodextrin functionalized magnetic adsorbents: Mechanisms and application.
abstract: In our work, the pH-controlled magnetic solid phase extraction for the determination of paraquat and diquat was introduced firstly. Furthermore, to clarify the mechanism of carboxymethyl-β-cyclodextrin functionalized magnetic adsorbents, we studied the pH-responsive supramolecular interaction between carboxymethyl-β-cyclodextrin (CM-β-CD) and paraquat/diquat by ultraviolet-visible (UV-vis) spectroscopy and nuclear magnetic resonance (NMR) experiment, and the energy-minimized structures were also obtained. Then, the functional group CM-β-CD was modified on the surface of magnetic materials to synthesize the adsorbent. The Fourier transform infrared spectrum (FT-IR) results proved the successful modification of CM-β-CD. Thus, this absorbent was applied for the determination of paraquat and diquat in water. Under the optimal condition, limits of detection (LODs) of paraquat and diquat were 0.8 μg L(-1) and 0.9 μg L(-1), relative standard deviations (RSD) and recoveries varied 0.7-4.6% and 86.5-106.6%, respectively. Good recoveries (70.2-100.0%) and low RSD (1.7-9.6%) were achieved in analyzing spiked water samples. Furthermore, with the capillary electrophoresis (CE) as the analyser, the whole analytical process did not need the attendance of organic solvents.
authors.affiliation: Department of Applied Chemistry, China Agricultural University, No. 2 West Yuanmingyuan Road, Beijing 100193, PR China.
authors.forename: Chang
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Applied Chemistry, China Agricultural University, No. 2 West Yuanmingyuan Road, Beijing 100193, PR China.
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.affiliation: Zhong Nong Fa Seed Industry Group Co. Ltd, Beijing 600313, PR China.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Shen
authors.affiliation: Department of Applied Chemistry, China Agricultural University, No. 2 West Yuanmingyuan Road, Beijing 100193, PR China.
authors.forename: Xueke
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Applied Chemistry, China Agricultural University, No. 2 West Yuanmingyuan Road, Beijing 100193, PR China.
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Department of Applied Chemistry, China Agricultural University, No. 2 West Yuanmingyuan Road, Beijing 100193, PR China. Electronic address: liudh@cau.edu.cn.
authors.forename: Donghui
authors.initials: D
authors.lastname: Liu
mesh_terms: D000327:Adsorption; D006540:Herbicides / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008280:Magnetics; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D006540:Herbicides; D000644:Quaternary Ammonium Compounds; D047392:beta-Cyclodextrins; C441457:carboxymethyl-beta-cyclodextrin
keywords: Green analytical chemistry; Host–guest chemistry; Magnetic solid phase extraction; Quaternary ammonium herbicides; pH-response