Impurity analysis of gentamicin bulk samples by improved liquid chromatography-ion trap mass spectrometry

Several gentamicin bulk samples from different origins were investigated using an LC/MS method. LC equipped with ion trap MS with positive ionization was performed on a Capcell Pak C18 (AQ) column with the mobile phase containing 50 mM trifluoroacetic (TFA) and methanol. Impurities present in batches of gentamicin bulk samples were elucidated and compared according to their fragmentation behavior. In total seventeen impurities present in samples, five impurities were not elucidated and two compounds were identified preliminarily. It was observed that the impurity profiles were different in samples from different origins which indicate necessity in the quality control of gentamicin.