Determination of residual thiamphenicol in yellow tail by high performance liquid chromatography

A high performance liquid chromatographic method (HPLC) was developed for the determination of thiamphenicol in yellow tails. The drug was extracted from homogenized yellow tail tissue with acetonitrile, followed by centrifugation. The supernatant was washed with n-hexane, and then the lower phase was evaporated to dryness. The residue was dissolved in ethyl acetate and washed with 5% sodium chloride solution. The ethyl acetate layer was concentrated and then cleaned up on a Florisil column to remove interfering substances. Thiamphenicol was eluted with acetone and determined by HPLC (with absorbance measurement at 225nm) on a TSK gel ODS-120T column (4mm×150mm) with methanol-water mixture (15:85v/v%) as a mobile phase. Recoveries of thiamphenicol added to yellow tail tissues at levels of 0.1, 0.2 and 0.5ppm were 82.9%, 87.7% and 94.1%, respectively. The lower limit of detection was 1.25ng. This method was considered to be suitable for residue analysis.