Analysis of underivatized gentamicin by capillary electrophoresis with UV detection

A selective and rapid capillary zone electrophoresis method for determination of the multicomponent aminoglycoside antibiotic gentamicin is described. Baseline separation of gentamicin C1, C1a, C2, C2a and C2b components was achieved with a background electrolyte containing 0.35 mM cetyl trimethylammonium bromide, 3% methanol and 90 mM sodium pyrophosphate (pH 7.4) and detected directly with UV detection without derivatization. Quantitative analysis was performed and illustrated the potential use of capillary electrophoresis for the identification and quantitation of gentamicin components, but the application of this method is limited to a gentamicin concentration range of 2–6 mg/ml.