Tatosian Irena J, Iacovino Anna C, Van Stipdonk Michael J
Department of Chemistry and Biochemistry, Duquesne University, 600 Forbes Avenue, Pittsburgh, PA, 15282, USA.
Rapid Commun Mass Spectrom. 2018 Jul 15;32(13):1085-1091. doi: 10.1002/rcm.8135. Epub 2018 May 27.
In a previous study [Rapid Commun Mass Spectrom. 2004;18:3028-3034], collision-induced dissociation (CID) of [U O (ClO )] appeared to be influenced by the high levels of background H O in a quadrupole ion trap. The CID of the same species was re-examined here with the goal of determining whether additional, previously obscured dissociation pathways would be revealed under conditions in which the level of background H O was lower.
Water- and methanol-coordinated [U O (ClO )] precursor ions were generated by electrospray ionization. Multiple-stage tandem mass spectrometry (MS ) for CID and ion-molecule reaction (IMR) studies was performed using a linear ion trap mass spectrometer.
Under conditions of low background H O, CID of [U O (ClO )] generates [U O (Cl)] , presumably by elimination of two O molecules. Using low isolation/reaction times, we found that [U O (Cl)] will undergo an IMR with H O to generate [U O (OH)] .
With lower levels of background H O, CID experiments reveal that the intrinsic dissociation pathway for [U O (ClO )] leads to [U O (Cl)] , apparently by loss of two O molecules. We propose that the results reported in the earlier CID study reflected a two-step process: initial formation of [U O (Cl)] by CID, followed by a very rapid hydrolysis reaction to leave [U O (OH)] .
在先前的一项研究[《快速通信质谱》。2004年；18:3028 - 3034]中，[UO(ClO)]的碰撞诱导解离（CID）似乎受到四极离子阱中高背景H₂O水平的影响。在此重新研究了同一物种的CID，目的是确定在背景H₂O水平较低的条件下是否会揭示出额外的、先前被掩盖的解离途径。
通过电喷雾电离产生水和甲醇配位的[UO(ClO)]前体离子。使用线性离子阱质谱仪进行用于CID和离子 - 分子反应（IMR）研究的多级串联质谱（MSⁿ）。
在低背景H₂O条件下，[UO(ClO)]的CID产生[UO(Cl)]⁺，推测是通过消除两个O₂分子。使用低隔离/反应时间，我们发现[UO(Cl)]⁺将与H₂O发生IMR以生成[UO(OH)]⁺。
在较低的背景H₂O水平下，CID实验表明[UO(ClO)]的固有解离途径导致[UO(Cl)]⁺，显然是通过失去两个O₂分子。我们认为早期CID研究中报道的结果反映了一个两步过程：通过CID最初形成[UO(Cl)]⁺，随后是非常快速的水解反应，留下[UO(OH)]⁺。
