Mass Spectrometry of Small Molecules: Magnetic-Sector Instruments Electron-impact,magnetic- sector instrument Sample is vaporized into ionization source Magnet Ionsdeflected Bombarded by electron beam according to m/z (70 eV)dislodging valence Heated filament electron of sample producing cation-radical RH 。 RH+.+e- Sample Organic Cation molecule radical beam LCD display Most cation-radicals fragment and are separated in magnetic field according to their mass-to- charge ratio (m/z) Since z 1 for most ions the value of mz is mass of ionElectron-impact, magnetic￾sector instrument ▪ Sample is vaporized into ionization source ▪ Bombarded by electron beam (70 eV) dislodging valence electron of sample producing cation-radical ▪ Most cation-radicals fragment and are separated in magnetic field according to their mass-to￾charge ratio (m/z) ▪ Since z = 1 for most ions the value of m/z is mass of ion Mass Spectrometry of Small Molecules: Magnetic-Sector Instruments