Simultaneous determination of tetracyclines in poultry muscle by capillary zone electrophoresis

A capillary zone electrophoresis method with UV detection was developed for the simultaneous detection and quantification of three tetracyclines in chicken meat samples: tetracycline (TC), oxytetracycline (OTC) and doxycycline (DOC). The separation conditions were: a running buffer containing 30 mM sodium phosphate, 2mM EDTA disodium salt and 2.5% 2-propanol, pH 12.0, a 5s hydrodynamic injection and a 14kV separation voltage. Two different clean-up methodologies were employed: solid-phase extraction with C(18) cartridges and ion exchange with Amberlite XAD7 resin. Analytes were detected at 360 nm in less than 12 min. LODs ranged from 61 microg kg(-1) for OTC to 68 microg kg(-1) for DOC with C(18) cartridges, and 81 microg kg(-1) for DOC to 89 microg kg(-1) for TC with Amberlite XAD7 resin. The recoveries for TC, OTC and DOC obtained by both methods were between 85 and 95%, and the peak area repeatability for all of the samples was below 5% in all cases. Twenty-four samples of commercial chicken drumsticks were examined with both clean-up methodologies. In nine cases (37.5%) TC was detected, in a range from 197.8 to 2564.3 microg kg(-1), and in seven cases (29.2%) OTC was detected in a range from 83.0 to 2049.3 microg kg(-1). DOC was not detected in any of the tested samples. This method would be useful for the routine monitoring of TCs residues in poultry muscle.