[Electrospray ion trap mass spectrometry of eight aminoglycoside antibiotics].

AIM

To study the dissociation pathways of aminoglycoside antibiotics.

METHODS

In positive mode, eight aminoglycoside antibiotics were elucidated by use of electrospray ion trap mass spectrometry in the multi-stage MS full scan mode.

RESULTS

It was demonstrated that the eight aminoglycoside antibiotics gave abundant product ions at m/z 322 (gentamicin, micronomicin and sisomicin), m/z 350 (etimicin, netilmicin and vetilmicin) and m/z 324 (kanamycin and tobramycin) by loss of the C-ring (amino-alpha-D-glucopyranose) in MS2 full scan mode. In MS3 full scan mode, the prominent fragmentation ions at m/z 163 as well as m/z 191 were formed from the fragmentation ions at m/z 322, m/z 350 and m/z 324 by loss of the A-ring (amino-alpha-D-glucopyranose), separately, while the characteristic fragmentation ions at m/z 160 as well as m/z 162 were formed from m/z 322, m/z 350 and m/z 324 by loss of the B-ring (2-deoxy-D-streptamine), separately.

CONCLUSION

The structural information was obtained via collision-activated dissociation and these characteristics are applicable to the structural elucidation and quantitative analysis of aminoglycoside compounds.