Capillary electrophoretic method for the simultaneous determination of tetracycline residues in fish samples

A capillary electrophoresis (CE) method with UV detection was developed for simultaneous identification and quantitation of three tetracyclines: tetracycline (TC), oxytetracycline (OTC) and doxycycline (DC) in fish muscle samples. It was developed by analyzing a series of fish tissue samples containing TCs in different concentrations. The CE method was validated in terms of linearity, sensitivity, selectivity, decision limit (CCalpha), detection capability (CCbeta), precision and accuracy for investigated TCs. The limits of detection (LODs) estimated in the range 1.3-1.8 ng/g, while the limits of quantification (LOQs) for all analyzed TCs were ranged from 4.3 to 5.9 ng/g. The overall recoveries for TC, OTC and DC were 84.0, 80.6 and 89.2%, respectively, with repeatabilities below 6.2% R.S.D. In this report the use of extended light path (ELP) silica capillary and aqueous buffer solutions are combined with low wavelength UV detection (ca. 200 nm) to obtain the necessary sensitivity for simultaneous TCs determination in biological samples.