Threshold Collision-Induced Dissociation Measurements Using a Ring Ion Guide as the Collision Cell in a Triple-Quadrupole Mass Spectrometer

Abstract

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.

Bond Dissociation Energies of Solvated Silver(I)−Amide Complexes: Competitive Threshold Collision-Induced Dissociations and Calculations

“…Losses of the solvent and ligand molecules can be represented in a thermodynamic cycle, see Figure . Published individual binding energies of Ag(I)−solvent (E 0 ( III )) and Ag(I)−amide (E 0 ( II )), , and bond dissociation energies obtained using direct fitting of the lower-energy channel (E 0 ( I )) (see Table S1 in Supporting Information) can be combined with the thermodynamic cycle to yield the value for the second, higher-energy channel (E 0 ( IV )), the loss of the amide ligand from the complex using: E 0 false( I V false) = E 0 false( bold-italicI false) + E 0 false( I I false) − E 0 false( I I I false) …”

“…To account for background ion generation, collision gas was diverted from the collision cell to the vacuum chamber. Collisional cross sections were measured with and without diverting the gas, and the difference for each data point was used to construct the background-subtracted TCID curve. , All E 0 values were determined four times, except for [Ag(CH 3 CONH 2 )] + and [Ag(CH 3 CN)] + , which were measured six times.…”

“…The TCID measurements were executed on a modified triple-quadrupole instrument using a ring ion guide as the collision cell. 37 Computational Method. Initial DFT calculations employed Becke's three-parameter hybrid functional formalism (B3LYP), involving Hartree-Fock exchange and Becke's exchange functionals 38,39 and the Lee-Yang-Parr correlation functional.…”

“…We compare the theoretical binding energies calculated using nine different functionals with binding energies of the doubly ligated silver complexes determined using competitive threshold collision-induced dissociation. The TCID measurements were executed on a modified triple-quadrupole instrument using a ring ion guide as the collision cell …”

Energy-Resolved Ion Mobility Spectrometry: Composite Breakdown Curves for Distinguishing Isomeric Product Ions

“…ERMS profiles allow (i) distinction of isomeric precursor ions, 10 (ii) a contribution to a better understanding of dissociations, even those taking place along complex pathways such as via an ion−dipole intermediate, 11 and (iii) estimation of E Threshold for selected ion dissociations. 12 Formation of a product ion with isomeric forms generated by different pathways from a precursor ion with one unique structure had not previously been described by ERMS using commercial tandem MS. However, Armentrout et al 13−16 achieved such a purpose using a custom-built guided ion beam tandem mass spectrometer (GIBMS) for threshold collisioninduced dissociation (TCID) measurements 15,17−19 from ERMS experiments.…”