Determination of tylosin in chicken, pork and beef by high-performance liquid chromatography.

A simple and rapid method for the determination of tylosin in chicken, pork and beef has been developed by high-performance liquid chromatography (HPLC). The drug was extracted from meat with 0.5% metaphosphoric acid-methanol (7 : 3), and followed by liquid-liquid partition for clean-up procedure. The HPLC separation was carried out on an Inertsil ODS column (25 cm×4.6 mm i.d.) using 0.05 M sodium dihydrogenphosphate (pH 2.4)-acetonitrile (65 : 35) as a mobile phase, and detected at 287 nm with 0.04 a.u.f.s. Although tylosin consists of four major components such as tylosin A, B, C and D, their molecular extinction coefficients at 287 nm maximum were virtually identical. Therefore, the method of calculating the contents of tylosin was carried out by total peak area normalization of peaks of tylosin A, B, C and D observed on the chromatogram. The calibration graph for tylosin was rectilinear from 10 to 200 ng. The average recoveries of tylosin added to chicken, pork and beef at the level 1.0 μg/g were 88.5, 88.4 and 84.5%, and the coefficients of variation were 2.5, 3.4 and 4.1%, respectively. The limits of detection of tylosin in chicken, pork and beef were 0.05μg/g. The accuracy and reproducibility of the present method were enough for residual analysis, and an excellent correlation (r=0.99) between the HPLC method and the bioassay method was obtained.