ABSTRACT
Objective To determine chloramphenicol and metronidazolel in honey by isotope-labelled internal standards ultra performance liquid chromatography-mass spectrometry.Methods Samples were extracted with ethyl acetate solution,and cleaned up on a MCS cartridge.The target analytes were separated on a ZORBAX SB-C18column with gradient elution using a mobile phase made up of methanol and 5 mmol/L ammonium acetate solution (containing 0.05％ formic acid).Detection was carried out using positive and negative electrospray ionization and multiple reaction monitoring (MRM),and quantified with isotope internal standardmethod.Results The chloramphenicol and metronidazolel showed good linearity in the range of 0.05-5.00 ng/ml.The recovery at three spiked levels of 0.5,2.0 and 5.0 μg/kg were in the range of 79.3％-96.7％.The relative standard deviation (RSD) was 5.5％-14.8％.The limits of quantitation were 0.15 μg/kg,the limits of detection were 0.05 μg/kg.Conclusion The method is sensitive and accurate.It could be applied to the high-throughput analysis of chloramphenicol and metronidazolel.