A method of high performance liquid chromatography with hollow fiber-based liquid phase microextraction(HF-LPME/HPLC) was developed for the analysis of four trace cephalosporin antibiotics

i.e.cefazolin(CZO)

cefuroxime(CXM)

ceftazidime(CAZ) and cefoxitin(FOX) in water.The optimized conditions were as follows:1-octyl-3-methylimidazolium hexafluorophosphate(［Omin］PF6) added with 10% trioctylphosphine oxide(TOPO) was selected as extraction solvent

in which TOPO was used for assisted extraction.The pH of sample solution was adjusted to 2.5.The extraction was conducted for 20 min at 30 ℃

with a stirring rate of 600 r/min.Four cephalosporin antibiotics were separated within 7 min on an Agilent Poroshell 120 EC-C18 column(100 mm×4.6 mm

2.7 μm) using 0.05 mol/L sodium acetate buffer(pH 4.0)-acetonitrile(9∶1

volume ratio) as mobile phase.Results showed that there were good linear relationships for four cephalosporin with the enrichment factors of 45-78 and the limits of detection(LOD) of 0.2-0.7 ng/mL.Recoveries for the four analytes ranged from 83.2% to 102%

with relative standard deviations(RSD) of 2.0%-9.8%.With the advantages of simple operation

high efficiency

low cost

low solvent consumption

environmental protection and high sensitivity

the proposed method was suitable for the determination of four trace cephalosporin residues in water.