Preconcentration of tetracycline antibiotics on a hyper-crosslinked polystyrene and their determination in waters by high-performance liquid chromatography

The possibility of using hyper-crosslinked polystyrene for the dynamic sorption preconcentration (solid-phase extraction) of tetracycline antibiotics (tetracycline, oxytetracycline, chlortetracycline, and doxycycline) from aqueous solutions has been studied. The conditions of the preconcentration of tetracyclines on a microcolumn filled with hyper-crosslinked polystyrene have been optimized. The compounds were desorbed with 2 mL of an acetonitrile-methanol mixture and determined in the eluate by reversed-phase HPLC with an amperometric detector. With preconcentration the limits of detection for tetracyclines were reduced by 90-100 times. The limits of detection were 0.6 ng/mL for oxytetracycline and tetracycline, 1 ng/mL for chlortetracycline, and 2 ng/mL for doxycycline. The method has been used for the analysis of model mixture based on river water.