Analysis of tobramycin by liquid chromatography with pulsed electrochemical detection

The determination of tobramycin by liquid chromatography using a column packed with poly(styrene-divinylbenzene) and pulsed electrochemical detection on a gold electrode is described. The mobile phase consisted of an aqueous solution containing 52 g/l of sodium sulfate, 1.5 g/l of sodium octanesulfonate and 50 ml/l of a 0.2 M phosphate buffer pH 3.0. The total time of analysis was not more than 30 min. The effects of the different chromatographic parameters on the separation were also investigated. When a number of commercial samples of tobramycin was analyzed using this method, nine different components were separated, five of which are of unknown identity.