Charge permutation reactions in beam type mass spectrometers

This is a review of the gas-phase reactions, in beam type mass spectrometers. that change the charge states of ions. The Cooks research group has been a leader in both the understanding and use of these charge-changing reactions. The charge of ions can be manipulated in beam type instruments via collisions with neutral gas atoms or molecules in the high ion kinetic energy regime. The two major processes, charge inversion and charge stripping due to high energy ion/neutral collisions, are discussed. Charge permutation reactions often result in the formation of unique ion structures that aid in the differentiation of isomers. The products of charge per-mutation reactions may possess excess internal energy that cause the ions to fragment, and these fragment ions may provide complementary information to that obtained from high energy collision-induced dissociation. The charge of ions also can be changed as a result of a collision with a surface in the low ion kinetic energy regime. Charge exchange and charge inversion processes that occur as a result of low energy ion/surface collisions are presented, (C) 2001 Elsevier Science B.V.