Electrospray ion trap mass spectrometry of eight aminoglycoside antibiotics

AimTo study the dissociation pathways of aminoglycoside antibiotics. MethodsIn positive mode, eight aminoglycoside antibiotics were elucidated by use of electrospray ion trap mass spectrometry in the multi-stage MS full scan mode. ResultsIt 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/z324 (kanamycin and tobramycin) by loss of the C-ring (amino-α-D-glucopyranose) in MS² full scan mode. In MS³ full scan mode, the prominent fragmentation ions at m/z 163 as well as m/z191 were formed from the fragmentation ions atm/z 322, m/z350 and m/z324 by loss of the A-ring (amino-α-D-glucopyranose), separately, while the characteristic fragmentation ions at m/z 160 as well as m/z162 were formed from m/z 322, m/z350 and m/z324 by loss of the B-ring (2-deoxy-D-streptamine), separately. ConclusionThe structural information was obtained via collision-activated dissociation and these characteristics are applicable to the structural elucidation and quantitative analysis of aminoglycoside compounds.