Abstract:

A high performance liquid chromatography-tandem mass spectrometric (HPLC-MS/MS) method was developed for the determination of chloramphenicol, thiamphenicol and florfenicol in animal muscles. Samples were spiked with deuterated chloramphenicol-d5 (d5-CAP) as internal standard and extracted with alkaline ethyl acetate. The resulting extract was then treated with n-hexane for the removal of lipids and injected directly into the HPLC-MS/MS system without the requirement of solidphase extraction clean-up. The electrospray ionization (ESI) mass spectrometry was run in negative ion multiple reaction monitoring mode. Instrumental parameters for MS analysis were optimized to maximize the detection sensitivity. The method exhibited the same limit of detection of up to 0.01μg/kg for the analytes. The internal standard method gave determination results closer to the actual values than the external method and the correlation coefficients of the linear regression equations developed for the determination of the analytes were all more than 0.9990. Mean recoveries of 5 replicates for chloramphenicol, thiamphenicol and florfenicol at the spike levels of 0.02－1μg/kg were within the ranges of 92.8%－97.0%, 93.5%－96.6% and 91.2%－ 95.9%, respectively.

Key words: high performance liquid chromatography-tandem mass spectrometry, animal muscles, chloramphenicol, thiamphenicol, florfenicol