title: Rapid magnetic-mediated solid-phase extraction and pre-concentration of selected endocrine disrupting chemicals in natural waters by poly(divinylbenzene-co-methacrylic acid) coated Fe3O4 core-shell magnetite microspheres for their liquid chromatography-tandem mass spectrometry determination.
abstract: A new Fe(3)O(4)/poly(divinylbenzene-co-methacrylic acid) core-shell magnetite microspheric material have been successfully developed as magnetic-mediated solid-phase extraction micro-particle sorbent in dispersion mode (MM-SPE-MP) for the determination of selected estrogenic endocrine disrupting chemicals (EDCs), namely: estrone (E1), 17beta-estradiol (E2), estriol (E3), 17alpha-ethynylestradiol (EE2) and bisphenol-A (BPA), in natural water, via quantification by HPLC tandem mass spectrometry. The magnetite Fe(3)O(4) core of this MM-SPE-MP sorbent was fabricated by a solvothermal approach and the thin layer of amphipolar poly(divinylbenzene-co-methacrylic acid) (pDVB-MAA) coating was established via suspension polymerization. The resultant core-shell MM-SPE-MP sorbent material was characterized by electron microscopy, X-ray diffraction and Fourier-transformed infrared spectroscopy. Particle size distribution of the core-shell microspheres was within the range 300-700 nm in diameter and the thickness of the pDVB-MAA coating was ca. 10nm. This magnetite microspheric material can be easily dispersed in aqueous samples and retrieved by the application of external magnetic field via a small piece of permanent magnet. The MM-SPE-MP process for the selected estrogenic EDCs involved the dispersion of the core-shell microspheric sorbent in water samples with sonication, followed by magnetic aided retrieval of the sorbent and solvent (methanol) desorption of extracted EDCs for LC-MS/MS analysis. Partition equilibrium for all the selected EDCs onto this MM-SPE-MP sorbent was achieved within 15 min. Recoveries of the EDCs were in ranges of 56-111%. Analytes with smaller K(OW) value showed relatively lower recovery (and relatively longer equilibration time for partitioning). Method detection limits achieved were found to be 1-36 pg ml(-1) (n=3), while the repeatability was 6-34% (p<0.05, n=3). This work demonstrates the usefulness of MM-SPE-MP in the rapid and highly sensitive monitoring of trace organic contaminants in natural waters.
authors.affiliation: Department of Biology & Chemistry, Centre of Coastal Pollution & Conservation, City University of Hong Kong, Tat Chee Ave, Kowloon, Hong Kong SAR, China.
authors.forename: Qingling
authors.initials: Q
authors.lastname: Li
authors.forename: Michael H W
authors.initials: MH
authors.lastname: Lam
authors.forename: Rudolf S S
authors.initials: RS
authors.lastname: Wu
authors.forename: Biwang
authors.initials: B
authors.lastname: Jiang
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D052244:Endocrine Disruptors / Q000032:analysis*; D052203:Ferrosoferric Oxide / Q000737:chemistry; D057230:Limit of Detection; D008280:Magnetics; D052616:Solid Phase Extraction / Q000191:economics / Q000295:instrumentation / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013997:Time Factors; D014867:Water / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D052244:Endocrine Disruptors; D014874:Water Pollutants, Chemical; D014867:Water; D052203:Ferrosoferric Oxide