On the detailed mechanisms of collision‐induced dissociation experiments performed by electrospray ion trap

Abstract

The product ion spectra obtained by electrospray ionization (ESI) ion trap instruments exhibit a higher number of fragment ions than those achieved by other ion-trap-based systems, indicating the presence of more effective energy deposition mechanisms. This behavior can be attributed to several different reasons, among which different initial internal energy of the precursor ions, pre-activation due to collisions taking place outside the trap, different target gas mixtures inside the trap, and different ion trap geometry were considered. Data obtained from experiments using a triple quadrupole instrument, CI-ion trap, and ESI-ion trap have been compared. The results so achieved seem to indicate that the presence inside the trap of neutral molecules of the solvent employed for the ESI process have a relevant role, promoting high energy deposition in the colliding ions.

Elucidation of the collision induced dissociation pathways of water and alcohol coordinated complexes containing the uranyl cation

“…Noting again the recent experiments that have demonstrated activating collisions between precursor ions and small molecules such as N 2 and H 2 O (He bath gas contaminants) [50], such a process is plausible. The presence of numerous, abundant H 2 O adducts in the MS n experiments show that significant levels of H 2 O are present within the He bath gas within the ion trap (Figures 2 and 3).…”

“…An alternative pathway for the formation of the m/z 287 product ion from the uranyl-alkoxy precursor ions might involve a reactive collision with an H 2 [50,51]. The reaction shown above would involve the ultimate elimination of EtOH, with a proton extracted from the H 2 O collision partner, and retention of the hydroxyl group by the uranyl ion.…”

Electrospray Ionization Mass Spectrometry of Palladium(II) Quinolinylaminophosphonate Complexes

“…It is interesting to note that a variety of aggregate ions including dimer and trimer species have been observed in the ESI-MS experiments of some palladium(II) and platinum(II) complexes derived from ethylenediamine, amidine, and azetidinone ligands [21,35,36]. As a general remark, it should be pointed out that by increasing the source collision energy, the cluster ions as well as the molecular ions became less abundant and the intensity of the ions obtained by complex fragmentation increased ( Figure S2) [37].…”

Production and collision‐induced dissociation of gas‐phase, water‐ and alcohol‐coordinated uranyl complexes containing halide or perchlorate anions

“…In this case, low‐energy collisions between [UO 2 Cl(H 2 O)] + and gas‐phase H 2 O may cause the formation of an activated version of [UO 2 Cl(H 2 O) 2 ] +* , which subsequently decomposes to form [UO 2 OH(H 2 O)] + by the elimination of HCl and retention of OH. The involvement of reactive collisions with indigenous H 2 O during the isolation step is plausible because of earlier accounts that have demonstrated the participation of small neutral molecules such as N 2 and H 2 O during CID in ion‐trap instruments when present as contaminants within the He buffer/bath gas 7, 8. In addition, the involvement of reactive collisions with gas‐phase H 2 O/D 2 O was demonstrated in an earlier study to account for the generation of [UO 2 OH] + from the CID of the uranyl‐2‐propoxide cation, [UO 2 OCH(CH 3 ) 2 ] + 4…”