Applications of Collision Dynamics in Quadrupole Mass Spectrometry

Abstract

Some applications of collision dynamics in the field of quadrupole mass spectrometry are presented. Previous data on the collision induced dissociation of ions in triple quadrupole mass spectrometers is reviewed. A new method to calculate the internal energy distribution of activated ions directly from the increase in the cross section for dissociation with center of mass energy is presented. This method, although approximate, demonstrates explicitly the high efficiency of transfer of translational to internal energy of organic ions. It is argued that at eV center of mass energies, collisions between protein ions and neutrals such as Ar are expected to be highly inelastic. The discovery and application of collisional cooling in radio frequency quadrupoles is reviewed. Some previously unpresented data on fragment ion energies in triple quadrupole tandem mass spectrometry are shown that demonstrate directly the loss of kinetic energy of fragment ions in the cooling process. The development of the energy loss method to measure collision cross sections of protein ions in triple quadrupole instruments is reviewed along with a new discussion of the effects of inelastic collisions in these experiments and related ion mobility experiments.