Fast determination of underivatized gentamicin C components and impurities by LC-MS using a porous graphitic carbon stationary phase.Gentamicin C antibiotics are important because they are active against many multidrug-resistant Gram-negative bacilli.  Under the described conditions, all analytes were eluted in less than 10 min and the LC-MS analyses exhibited excellent stability and linearity. 
LC-MS
Here, we assess the usefulness of a porous graphitic carbon (PGC) HPLC column for separating the components of gentamicin C, and report chromatographic conditions that enable its direct characterization by PGC chromatography directly coupled to electrospray mass spectrometry. 
HPLC
Here, we assess the usefulness of a porous graphitic carbon (PGC) HPLC column for separating the components of gentamicin C, and report chromatographic conditions that enable its direct characterization by PGC chromatography directly coupled to electrospray mass spectrometry. 
electrospray mass spectrometry
When coupled with detection by conventional electrospray ion trap mass spectrometry (ESI-IT-MS), several previously reported impurities were detected easily, including the most polar gentamicin impurity, garamine. 
ESI-IT-MS
When the PGC chromatographic system was coupled to an evaporative light-scattering detector, detection limits of 40-70 ng were achieved for various major gentamicin components. 
evaporative light-scattering detector