Huo Xinming, Chen Jin, Tang Fei, Yao Tongtong, Piao Shiyun, Ni Kai, Wang Xiaohao
State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China.
Division of Advanced Manufacturing, Graduate School at Shenzhen, Tsinghua University, Shenzhen, 518055, China.
Rapid Commun Mass Spectrom. 2017 Jun 30;31(12):1031-1040. doi: 10.1002/rcm.7880.
Secular frequency scanning is a mass spectrometry (MS) analysis method in which the frequency of the auxiliary alternating current (AC) signal is scanned. It has low requirements for radio-frequency (RF) power, which is beneficial for the miniaturization of the mass spectrometer. In this study, the MS performance in the reverse secular frequency scanning (RSFS) mode is optimized for a rectilinear ion trap (RIT), and a method for rapid MS analysis using continuous secular frequency scanning (CSFS) is proposed.
A RIT mass spectrometer with an auxiliary AC frequency scanning function was built. The resolution, tandem mass spectrometry (MS/MS) and quantitation capability in the RSFS mode were characterized and optimized. Operation in the CSFS mode was then performed by scanning the frequency of the auxiliary AC signal continuously and periodically while maintaining the RF signal and the front Z electrode in the ion injection state, so that the ion injection and cooling were performed at the same time as the mass analysis.
With this system, the RSFS mode achieved unit mass resolution at 332 Th, and the MS/MS analysis was completed without changing the RF amplitude at q = 0.4583 for reserpine. The limit of quantitation for imatinib was about 250 ng/mL with the determination coefficient R = 0.9981. In the CSFS mode, a single analysis cycle of less than 20 ms could be achieved, which is 14 times faster than the traditional sweep modes. In addition, 100% ion utilization can theoretically be achieved in the CSFS mode.
The CSFS mode is different from the traditional phased sequential operation mode of an ion trap mass spectrometer. By periodic scanning of the auxiliary AC frequency while maintaining ion injection, it is possible to improve the analysis efficiency of the mass spectrometer, which has the prospect of useful application in the field of rapid MS monitoring. Copyright © 2017 John Wiley & Sons, Ltd.
长期频率扫描是一种质谱（MS）分析方法，其中辅助交流（AC）信号的频率被扫描。它对射频（RF）功率要求较低，这有利于质谱仪的小型化。在本研究中，针对直线离子阱（RIT）优化了反向长期频率扫描（RSFS）模式下的质谱性能，并提出了一种使用连续长期频率扫描（CSFS）进行快速质谱分析的方法。
构建了具有辅助交流频率扫描功能的RIT质谱仪。对RSFS模式下的分辨率、串联质谱（MS/MS）和定量能力进行了表征和优化。然后通过在保持RF信号和前Z电极处于离子注入状态的同时，连续且周期性地扫描辅助交流信号的频率来进行CSFS模式下的操作，从而使离子注入和冷却与质量分析同时进行。
使用该系统，RSFS模式在332 Th处实现了单位质量分辨率，并且在利血平的q = 0.4583时，无需改变RF幅度即可完成MS/MS分析。伊马替尼的定量限约为250 ng/mL，测定系数R = 0.9981。在CSFS模式下，单个分析周期可小于20 ms，比传统扫描模式快14倍。此外，理论上在CSFS模式下可实现100%的离子利用率。
CSFS模式不同于离子阱质谱仪的传统分阶段顺序操作模式。通过在保持离子注入的同时周期性扫描辅助交流频率，可以提高质谱仪的分析效率，在快速质谱监测领域具有应用前景。版权所有© 2017 John Wiley & Sons, Ltd.
