Development of a screening method for analytical control of antibiotic residues by micellar electrokinetic capillary chromatography

Capillary electrophoresis was used for the separation of penicillin compounds. Micellar electrokinetic capillary chromatography (MEKC), by the addition of sodium dodecyl sulphate (SDS) to the buffer solution, demonstrated to be the appropriate mode for the separation of these compounds and their monitoring in drug residues. The method allowed to separate a mixture of antibiotics, such as amoxicillin, ampicillin, penicillin G, oxacillin, penicillin V, and cloxacillin. A mixture of 40 mM sodium tetraborate and 100 mM SDS at pH 8.5 was used as running buffer. The analysis was performed with a voltage of 10 kV at a temperature of 20 °C. The samples were hydrostatically introduced (10 s) into the capillary and electropherograms were recorded at 210 nm. Statistical analysis by Studentʹs t-test showed no significant evidence of systematic errors in the proposed method. This method proved to be highly suitable for the separation and determination of penicillins (at (mu)g ml^-1 level) in farm water samples, where the presence of these compounds can produce an environmental problem.