Analysis of gentamicin by liquid chromatography with pulsed electrochemical detection

The analysis of gentamicin by liquid chromatography using a column packed w ith poly(styrene-divinylbenzene) and pulsed electrochemical detection on a gold electrode is described. The mobile phase consists of an aqueous soluti on containing sodium sulfate, tetrahydrofuran, sodium 1-octanesulfonate and a phosphate buffer of pH 3.0. In contradistinction to methods previously p ublished, this method not only allows a better separation of gentamicins C- 1, C-1a, C-2, C-2a and C-2b, but also the separation of several other, mino r components, most of which were not identified. The effects of the differe nt chromatographic parameters on the separation were also investigated. A n umber of commercial samples was analysed using this method, allowing sensit ive detection of gentamicin without derivatization, and the results were co mpared with the results obtained with the European Pharmacopoeia method, pr escribing pre-column derivatization. (C) 1998 Elsevier Science B.V. All rig hts reserved.