Threshold collision-induced dissociation measurements using a ring ion guide as the collision cell in a triple-quadrupole mass spectrometer.

A triple-quadrupole mass spectrometer has been modified for bond-dissociation energy measurements via threshold collision-induced dissociations (TCIDs) by replacing the conventional collision cell with a ring ion guide. Optimal operating conditions for the ring ion guide were determined or derived, and validated using a set of complexes for which bond dissociation energies are known. A comparison with reference data (within a range of 16-57 kcal/mol) indicates an accuracy approaching that of TCID determined on a guided ion-beam mass spectrometer. Complexes for which bond-dissociation energies were measured include metal ion complexes of simple ligands, amino acids and peptides, as well as of carbonic acid. There is excellent agreement between our experimental data and literature data, as well as theoretical data determined using a high-level computational method.