Analysis of impurities in vertilmicin sulfate by liquid chromatography ion-trap mass spectrometry.

The characterization of impurities present in vertilmicin by liquid chromatography (LC) coupled with mass spectrometry (MS) is described. A reversed phase (RP)-LC method using a C18 column resistant to basic pH with an alkaline (pH 11) aqueous mobile phase was developed and coupled to MS with an electrospray ionization (ESI) source in the positive ion mode which provides MS(n) capability. In total, 18 impurities were detected in a commercial sample. Eleven impurities described in this work were newly identified.