Department of Chemistry , Purdue University , West Lafayette , Indiana 47907-2084 , United States.
Anal Chem. 2019 Oct 1;91(19):12574-12580. doi: 10.1021/acs.analchem.9b03560. Epub 2019 Sep 19.
Simultaneous isolation of ions of disparate mass-to-charge (/) ratios is demonstrated via appropriately timed pulsing of entrance and exit ion mirrors in an electrostatic linear ion trap (ELIT) mass spectrometer. Manipulation of the voltages of the entrance and exit mirrors, referred to as "mirror switching", has been demonstrated as a method in which ions can be both captured and isolated. High resolution isolation (>35 000) was previously demonstrated by selective gating of trapping electrodes to avoid ion lapping while closely spaced ions could continue to separate [ Johnson et al. 2019 , 91 , 8789 ]. In this work, we demonstrate that advantage can be taken of the ion lapping phenomenon in an ELIT to enable the simultaneous isolation of ions of disparate / ratios using mirror switching. This process is demonstrated with minimal ion loss using isotopologues of three carborane compounds ranging in / from 320 to 1020. Simultaneous isolation is demonstrated with the isolation of two and three peaks in separate isotopic distributions as well as with the isolation of alternating isotopologues within the same distribution. Such simultaneous isolation experiments are particularly useful when conducting experiments in which a mass calibrant is needed or when multiplexing in a tandem MS workflow.
通过在静电线性离子阱（ELIT）质谱仪中适时脉冲进入和离开离子镜，可实现不同质荷比（/）的离子同时分离。这种通过控制进入和离开离子镜的电压（称为“镜切换”）来操纵离子的方法已被证明可用于离子捕获和隔离。先前的研究已经证明，通过选择性地门控捕获电极，可以实现高分辨率的隔离（>35000），从而避免离子重叠，而紧密间隔的离子可以继续分离[Johnson 等人，2019 年，91，8789]。在这项工作中，我们证明可以利用 ELIT 中的离子重叠现象，通过镜切换来实现不同/比的离子的同时分离。使用从 320 到 1020 不等的三种碳硼烷化合物的同位素对，我们演示了这一过程，离子损失最小。我们通过在单独的同位素分布中隔离两个和三个峰以及在同一分布中隔离交替的同位素对来证明同时分离。当在需要质量校准剂的实验中或在串联 MS 工作流程中进行多重实验时，这种同时分离实验特别有用。
