Ion Confinement in the Collision Cell of a Multiquadrupole Mass Spectrometer: Access to Chemical Equilibrium and Determination of Kinetic and Thermodynamic Parameters of an Ion-Molecule Reaction

Article abstract of DOI:10.1021/ac00188a029

Ions can be confined in an rf-only collision cell of a tandem quadrupole mass spectrometer so that ion-molecule reactions can be studied for variable interaction times (0.05-250 ms).The chemical system studied (ammonium ion, pyrrolidine, piperidine) involved the following reactions: proton exchange, formation of proton-bound dimers, and amine exchange between dimers.Chemical equilibrium could be reached for the exchange reactions.The equilibrium constants of these reactions, as well as the rate constants of the different reactions involved, were thus easily determined from the variation of relative abundance of reactant and product ions versus confinement time.