Mass Spectrum of Benflumetol:Comparison of FAB-MS,ESI-MS and EI-MS

FAB-MS and ESI-MS of benflumetol were measured and compared with its EI-MS.It was shown that ESI is the most soft technique for benflumetol ionization.FAB-MS of benflumetol is similar to EI-MS.In both mass spectra the main fragmentation is β-cleavage of its side amine chain and the base peak is m/z 142CH 2= +N(C 4H 9) 2ion.When in-source CID is measured in ESI-MS,the first fragmentation step of benflumetol is dehydration and then fragmentation.