Determination of chloramphenicols in the eels by UPLC-MS / MS

The aim of this experiment was to establish an ultra performance liquid chromatography-tandem mass spectrometry（ UPLC-MS /MS） method to detect chloramphenicol,thiamphenicol and florfenicol residues in the eel muscles. Twenty millilitres of alkaline ethyl acetate was used to extract chloramphenicols in the tissue under adding anhydrous sodium sulfate and sodium chloride. The combined elution was evaporated to dryness under nitrogen stream in a water bath maintained at 45 ℃. The residues were reconstituted in 5% methanol solution together with n-hexane saturated by 5% methanol to remove fat. The upper layer of n-hexane was discarded,and the lower aqueous phase was poured through a 0. 22 μm filter into UPLC-MS / MS. The results showed that the calibration curves were good linear at the concentrations of0. 5 50 μg·L -1 . The detection limit of chloramphenicol,thiamphenicol and florfenicol was 0. 1 μg·kg -1 and the limit of quantification was 0. 3 μg· kg -1 . The average recoveries of chloramphenicol at concentrations of 0. 3,0. 45 and 0. 6 μg · kg -1 were from 92. 83% to111. 26%,thiamphenicol at 25,50 and 75 μg·kg -1 ranged from 86. 76% to 107. 30% and florfenicol at 50,100 and 150 μg·kg -1 were from 96. 21% to 104. 14%. The average recoveries were from 86. 76% to 111. 26%,the Intra-day RSD of this method was from 2. 16% to13. 66%,and the Inter-day RSD was from 1. 42% to 8. 06%. In conclusion,the method established in this study greatly improved detection efficiency on the basis of ensuring the recovery.