Fabrication of CoFe2O4–graphene nanocomposite and its application in the magnetic solid phase extraction of sulfonamides from milk samples

• Published in: Talanta (Oxford) 2015-11, Vol.144, p.1279-1286
• Main Authors: Li, Yazhen, Wu, Xuewen, Li, Zhaoqian, Zhong, Shuxian, Wang, Weiping, Wang, Aijun, Chen, Jianrong
• Format: Article
• Language: English
• Subjects: Animals; Cobalt - chemistry; CoFe2O4–graphene nanocomposite; Drug Residues - analysis; Drug Residues - isolation & purification; Ferric Compounds - chemistry; Food Contamination - analysis; Graphite - chemistry; High performance liquid chromatography; Hydrogen-Ion Concentration; Limit of Detection; Magnetic solid phase extraction; Magnets - chemistry; Milk - chemistry; Milk sample; Models, Molecular; Molecular Conformation; Nanocomposites - chemistry; Solid Phase Extraction - methods; Solvents - chemistry; Sulfonamides; Sulfonamides - analysis; Sulfonamides - isolation & purification; Time Factors
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2015.08.006

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 0.02–50.00mgL−1 with correlation coefficients (r)≧0.9982. The limits of detection were less than 1.59μgL−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 20μgL−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. The procedure of MSPE using magnetic CoFe2O4–graphene. [Display omitted] •CoFe2O4–graphene nanocomposite was used successfully as adsorbent for sulfonamides.•Parameters affecting extraction efficiency were investigated in detail.•Limits of detection less than 1.59μgL−1 were obtained.•The method was successfully applied for milk samples.