Development of method for simultaneous determination of chloramphenicol, thiamphenicol, florfenicol and florfenicol amine residues in chicken tissues by LC-MS/MS.

A liquid chromatography-tandem mass spectrometry(LC-MS/MS) method was developed for the simultaneous determination of chloramphenicol(CAP),thiamphenicol(TAP),florfenicol(FF) and florfenicol amine(FFA) in chicken tissues.The samples were extracted by ethyl acetate in basic conditions,defatted with hexane and evaporated to dryness,followed by a clean-up step using the solid phase extraction with MCX.The eluent was filtered through 0.22 μm membrane and then analyzed by LC-MS/MS.Mass spectral acquisition was done using electrospray ionization in the switched ion mode applying multiple reaction monitoring.The calibration curve of mixed standard solution showed a good linearity in the concentration range from 2 to 100 ng?mL-1 with the correla-tion coefficients(r) more than 0.990.The LOD(limit of detection) of chloramphenicol was 0.1 μg/kg,and the limit of quantification(LOQ) was 0.3 μg?kg-1.The LOD of florfenicol was 0.2 μg?kg-1,and the LOQ was 0.5 μg/kg.Both the LODs of thiamphenicol and florfenicol amine were 0.2 μg?kg-1,and the LOQs were 1.0μg?kg-1.The average re-coveries of 4 drugs ranged from 79.3% to 97.3%.The relative standard deviation(RSD) of the method was less than 20%.The method is useful for monitoring chloramphenicol,thiamphenicol and florfenicol residues in chicken tissues,and the most important metabolite can also be separated and quantitated.