EXPERIMENTAL ASPECTS OF THE COLLISION-INDUCED DECOMPOSITION OF IONS IN A 4-SECTOR TANDEM MASS-SPECTROMETER

The collision-induced decomposition (CID) of ions in the collision cell of a four-sector tandem mass spectrometer (EBEB) was studied as a function of cell potential and collision gas over the mass range 246-1847. When the cell is at a potential of 2 kV or greater above earth, the loss of light ions by scattering is negligible and the detection sensitivity for light ions increases owing to their being reaccelerated on leaving the cell. The CID spectra given by helium and argon are very similar for ions derived from samples of m/z less-than-or-equal-to 1000 but at higher masses argon is the more efficient collision gas.