title: Fabrication of CoFe2O4-graphene nanocomposite and its application in the magnetic solid phase extraction of sulfonamides from milk samples.
abstract: In the present study, a graphene-based magnetic nanocomposite (CoFe2O4-graphene, CoFe2O4-G) was synthesized and used successfully as an adsorbent for the magnetic solid phase extraction (MSPE) of sulfonamides for the first time. The surface morphologies and structures of the CoFe2O4-G nanocomposite were investigated by scanning electron microscopy (SEM), FT-IR, UV-vis spectroscopy, X-ray diffraction (XRD) and vibration sample magnetometer (VSM). Five sulfonamides, including sulfamerazine, sulfamethizole, sulfadoxine, sulfamethoxazole and sulfisoxazole were used as model analytes to evaluate the enrichment properties of the prepared adsorbent in MSPE. After preconcentration, the adsorbent could be conveniently separated from the aqueous samples by an external magnet, and the analytes desorbed from adsorbent were determined by high performance liquid chromatography-ultraviolet detection (HPLC-UV). Extraction parameters including sample pH, amount of sorbent, extraction time and desorption conditions were optimized in detail. Under the optimal conditions, good linear relationships between the peak areas and the concentrations of the analytes were obtained. The linear ranges were 0.02-50.00 mg L(-1) with correlation coefficients (r)≧0.9982. The limits of detection were less than 1.59 μg L(-1). Good reproducibility was obtained. The relative standard deviations of intra- and inter-day analysis were less than 4.3% and 6.5%, respectively. The proposed method was successfully applied for the analysis of sulfonamides in milk samples. The average recoveries determined for two milk samples spiked at levels from 5 to 20 μg L(-1) were 62.0-104.3% with relative standard deviations less than 14.0%. In addition, the CoFe2O4-G could be reused after cleaning with acetone and ultrapure water successively.
authors.affiliation: College of Chemistry and Life Science, Zhejiang Normal University, Jinhua 321004, China.
authors.forename: Yazhen
authors.initials: Y
authors.lastname: Li
authors.affiliation: College of Chemistry and Life Science, Zhejiang Normal University, Jinhua 321004, China.
authors.forename: Xuewen
authors.initials: X
authors.lastname: Wu
authors.affiliation: College of Chemistry and Life Science, Zhejiang Normal University, Jinhua 321004, China.
authors.forename: Zhaoqian
authors.initials: Z
authors.lastname: Li
authors.affiliation: College of Chemistry and Life Science, Zhejiang Normal University, Jinhua 321004, China.
authors.forename: Shuxian
authors.initials: S
authors.lastname: Zhong
authors.affiliation: College of Chemistry and Life Science, Zhejiang Normal University, Jinhua 321004, China. Electronic address: wangwp@zjnu.edu.cn.
authors.forename: Weiping
authors.initials: W
authors.lastname: Wang
authors.affiliation: College of Geography and Environmental Science, Zhejiang Normal University, Jinhua 321004, China.
authors.forename: Aijun
authors.initials: A
authors.lastname: Wang
authors.affiliation: College of Geography and Environmental Science, Zhejiang Normal University, Jinhua 321004, China.
authors.forename: Jianrong
authors.initials: J
authors.lastname: Chen
mesh_terms: D000818:Animals; D003035:Cobalt / Q000737:chemistry*; D004350:Drug Residues / Q000032:analysis / Q000302:isolation & purification*; D005290:Ferric Compounds / Q000737:chemistry*; D005506:Food Contamination / Q000032:analysis; D006108:Graphite / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D059346:Magnets / Q000737:chemistry*; D008892:Milk / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D053761:Nanocomposites / Q000737:chemistry*; D052616:Solid Phase Extraction / Q000379:methods*; D012997:Solvents / Q000737:chemistry; D013449:Sulfonamides / Q000032:analysis / Q000302:isolation & purification*; D013997:Time Factors
chemical_list: D005290:Ferric Compounds; D012997:Solvents; D013449:Sulfonamides; C569492:cobalt ferrite; D003035:Cobalt; D006108:Graphite
keywords: CoFe(2)O(4)–graphene nanocomposite; High performance liquid chromatography; Magnetic solid phase extraction; Milk sample; Sulfonamides