title: Fabrication of magnetic microsphere-confined graphene for the preconcentration of some phthalate esters from environmental water and soybean milk samples followed by their determination by HPLC.
abstract: In this study, a magnetic microsphere-confined graphene (Fe3O4@SiO2-G) was prepared as a novel adsorbent for the preconcentration of some phthalate esters in environmental water and soybean milk samples prior to high performance liquid chromatography analysis. The properties and morphology of the Fe3O4@SiO2-G were characterized by transmission electron microscopy and X-ray diffraction. This novel graphene-based magnetic nanocomposite showed great adsorptive ability toward the analytes. The method, which takes the advantages of both the high adsorption capacity of G and easy phase separation of the magnetic adsorbent from the sample solution, could avoid the time-consuming experimental procedures related to the traditional solid phase extraction. Various experimental parameters that could affect the extraction efficiencies, such as the amount of Fe3O4@SiO2-G, the extraction time, the pH of sample solution and the desorption conditions, were investigated. Under the optimum conditions, the limits of detection (S/N=3) of the method for the compounds were between 0.07 and 0.10 ng mL(-1) in water samples, and between 0.15 and 0.30 ng mL(-1) in soybean milk samples. The relative standard deviations (RSDs) varied from 2.7% to 6.1% (n=5). The recoveries of the method were in the range between 87.2% and 109.0% for environmental water and soybean milk samples. The method is suitable to determine the five phthalate esters (diallyl phthalate, di-n-propyl-phthalate, benzyl butyl phthalate, dicyclohexyl-phthalate and diethyl-hexyl-phthalate) in environmental water and soybean milk samples.
authors.affiliation: Department of Chemistry, College of Basic Sciences, Agricultural University of Hebei, Baoding, Hebei, China.
authors.forename: Weina
authors.initials: W
authors.lastname: Wang
authors.forename: Ruiyang
authors.initials: R
authors.lastname: Ma
authors.forename: Qiuhua
authors.initials: Q
authors.lastname: Wu
authors.forename: Chun
authors.initials: C
authors.lastname: Wang
authors.forename: Zhi
authors.initials: Z
authors.lastname: Wang
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation / Q000379:methods*; D004952:Esters / Q000032:analysis; D005618:Fresh Water / Q000032:analysis*; D006108:Graphite / Q000737:chemistry*; D057230:Limit of Detection; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D008863:Microspheres; D010795:Phthalic Acids / Q000032:analysis*; D012822:Silicon Dioxide / Q000737:chemistry; D041942:Soy Milk / Q000737:chemistry*; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D004952:Esters; D058185:Magnetite Nanoparticles; D010795:Phthalic Acids; D012822:Silicon Dioxide; D006108:Graphite