Determination of tetracycline residues in honey by CZE with ultraviolet absorbance detection

We have developed a sensitive CE method to determine eight tetracyclines (TCs) (chlortetracycline, demeclocycline, doxycycline, methacycline, minocycline, oxytetracycline, TC, and rolitetracycline (RTC)) in honey samples. The running buffer was 150 mM sodium borate (pH 9.8) and 2.5% 2-propanol with 15 s hydrodynamic injection at 25 kV. We have also developed an SPE procedure with a C18 cartridge as a clean-up step. Analytes were detected at 360 nm in less than 16 min. LODs ranged in honey from 23.9 microg/kg for TC to 49.3 microg/kg for RTC. Seven samples of Spanish honey of different floral origins were examined. None of them showed contamination with these antibiotics using the proposed method.