Aqueous two-phase solvent sublation-HPLC for determining tilmicosin residues in environment water samples

The separation/enrichment of tilmicosin was studied based on the system of aqueous two phase-gas solvent subblation, the method of HPLC was established to determin tilmicosin enriched. The optimal condition of the solvent sublation was obtained: the sublation solvent was n-propanol. the salting-out agent was (NH₄)₂SO₄ with 36% (g/100ml), the pH was 3, N₂ flow rate was 20 ml/min, the sublation time was 30 min.The flotation efficiency under the optimum conditions was 84.7%, enrichment multiple was 16.8. And compared with the solvent extration, the solvent sublation had many merits, such as high enrichment factor, large volume of water sample, n-propanol with less, no emulsification, etc. The method is suitable for determining the antibiotics residue in environment sample.