Improved Quantitative Dynamic Range of Time-of-Flight Mass Spectrometry by Simultaneously Waveform-Averaging and Ion-Counting Data Acquisition
Improved Quantitative Dynamic Range of Time-of-Flight Mass Spectrometry by Simultaneously Waveform-Averaging and Ion-Counting Data Acquisition
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DOI：
10.1007/s13361-018-1967-1
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发表时间：
2018-07-01
影响因子：
3.2
通讯作者：
Terada, Kentaro
中科院分区：
文献类型：
--
作者：
Kawai, Yosuke;Hondo, Toshinobu;Terada, Kentaro
两种不同类型的数据采集方法，“平均模式”和“离子计数模式”，已被用于飞行时间（TOF）质谱。最常用的方法是平均模式，将从每个飞行周期获得的波形信号相加。虽然可以处理在一个飞行周期中到达相同TOF的许多离子，但是低丰度离子难以测量，因为离子信号被来自检测系统的噪声淹没。离子计数模式适合于检测这样的低浓度离子，但是当两个或更多个离子在采集系统的死区时间内到达检测器时，发生计数损失。在这项研究中，我们介绍了一种技术，结合两种方法来测量具有高浓度差的目标离子，即，平均模式和离子计数模式分别同时用于高丰度和痕量离子。通过在数据采集期间同时处理波形，可以选择分析任一种或两种类型的数据，以在宽范围的样品浓度上实现高度定量的质谱。氩同位素分析的结果表明，该方法提供了一个更准确的同位素比的测定相比，平均模式单独的离子计数单独所需的分析时间的二十分之一。
Two different types of data acquisition methods, "averaging mode" and "ion-counting mode", have been used in a time-of-flight (TOF) mass spectrometry. The most common method is an averaging mode that sums waveform signals obtained from each flight cycle. While it is possible to process many ions arriving at the same TOF in one flight cycle, low-abundance ions are difficult to measure because ion signals are overwhelmed by noises from the detection system. An ion-counting mode is suitable for the detection of such low-concentration ions, but counting loss occurs when two or more ions arrive at the detector within the dead time of the acquisition system. In this study, we introduce a technique that combines two methods to measure target ions with a high concentration difference, i.e., averaging mode and ion-counting mode are used simultaneously for high abundant and trace ions, respectively. By processing waveforms concurrently during data acquisition, one can choose to analyze either or both types of data to achieve a highly quantitative mass spectrum over a wide range of sample concentrations. The result of the argon isotope analysis shows that this method provides a more accurate determination of the isotope ratio compared to averaging mode alone at one-twentieth of the analysis time required by ion-counting alone.