10-2 Interpreting Mass Spectra Molecular weight determined from molecular ion peak -High resolution double-focusing mass spectrometers are accurate to about 0.0005 amu M+1 peak results from presence of 13C and 2H Fragmentation occurs when high-energy cation radical falls apart One fragment retains positive charge and is a carbocation One fragment is a neutral radical fragmentMolecular weight determined from molecular ion peak ▪ High resolution double-focusing mass spectrometers are accurate to about 0.0005 amu ▪ M+1 peak results from presence of 13C and 2H ▪ Fragmentation occurs when high-energy cation radical falls apart ▪ One fragment retains positive charge and is a carbocation ▪ One fragment is a neutral radical fragment 10-2 Interpreting Mass Spectra