Linden CMS, Auf dem Berge 25, 28844, Weyhe, Germany.
Institute of Organic Chemistry, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany.
J Am Soc Mass Spectrom. 2019 Nov;30(11):2358-2368. doi: 10.1007/s13361-019-02297-1. Epub 2019 Aug 2.
A new implementation of a dedicated ion source for field ionization (FI), field desorption (FD), and liquid injection field desorption/ionization (LIFDI) for the JEOL AccuTOF GC series of orthogonal-acceleration time-of-flight instruments is presented. In contrast to existing implementations, this third-party LIFDI probe and source combination does not require the exchange of the entire ion source comprising ion source block and lens stack to switch from electron ionization (EI) to LIFDI. Rather, the methods may be swapped conveniently by only exchanging the ion source block for a mechanical probe guide and inserting the LIFDI probe in place of the standard direct insertion probe (DIP) via the vacuum lock. Further, this LIFDI setup does not require any changes of the electronics or software of the AccuTOF mass spectrometer because it is self-supplied in terms of power supply, observation optics, and computer control. The setup offers advanced FI/FD/LIFDI control features such as emission-controlled emitter heating current and emitter flash baking during elongated runs as required for gas chromatography-FI-mass spectrometry (MS). The LIFDI source and probe and its operation are reported in detail. FI spectra of the volatile analytes toluene, heptane, and pentafluoroiodobenzene are presented. LIFDI operation is demonstrated for the analysis of the saturated hydrocarbon dotriacontane and the low-mass hydrocarbon polymers polystyrene 484 and polystyrene 1050. Further, the air-sensitive 2nd-generation Hoveyda-Grubbs catalyst is analyzed by LIFDI-MS. For comparison with long-established LIFDI instrumentation, some of the spectra obtained with the new setup are also compared with those from a double-focusing magnetic sector instrument.
一种新的专用场致电离（FI）、场解吸（FD）和液体喷射场解吸/电离（LIFDI）离子源的实现方案，用于 JEO L AccuTOF GC 系列正交加速飞行时间仪器。与现有实现方案相比，这种第三方 LIFDI 探头和源组合不需要更换整个离子源，包括离子源块和透镜组，即可从电子电离（EI）切换到 LIFDI。相反，可以通过仅更换离子源块为机械探头导向器，并通过真空锁将 LIFDI 探头插入标准直接插入探头（DIP）的位置，方便地进行方法交换。此外，这种 LIFDI 装置不需要对 AccuTOF 质谱仪的电子设备或软件进行任何更改，因为它在电源、观察光学器件和计算机控制方面都是自给自足的。该装置提供了先进的 FI/FD/LIFDI 控制功能，例如在需要进行气相色谱-FI-质谱（MS）的情况下，发射控制的发射器加热电流和发射器闪光烘焙。详细报告了 LIFDI 源和探头及其操作。展示了挥发性分析物甲苯、庚烷和五氟碘苯的 FI 光谱。演示了 LIFDI 操作，用于分析饱和烃三十烷和低质量烃聚合物聚苯乙烯 484 和聚苯乙烯 1050。此外，通过 LIFDI-MS 分析了空气敏感的第二代 Hoveyda-Grubbs 催化剂。为了与成熟的 LIFDI 仪器进行比较，还将一些用新装置获得的光谱与来自双聚焦磁扇形仪器的光谱进行了比较。
