Flowing afterglow tandem mass spectrometer

Figure 6, The flowing afterglow-tandem mass spectrometer. Hypervalent anions are formed and cooled in the flow tube, and collision-induced dissociation occurs in the quadrupole-octopole-quadrupole tandem mass spectrometer.

Most of the studies in this decade were carried out with conventional single source mass spectrometers, which limited the kind and accuracy of the information. During the next decade, however, various sophisticated techniques for the study of ion—molecule reactions, such as tandem mass spectrometers, photoionization sources, pulsed sources, flowing afterglow and drift tube methods, crossed and merging beams and ion cyclotron resonance, have been developed. Much detailed information on various aspects of ion—molecule reactions has accumulated, and this has consequently stimulated the theoretical studies as well. This decade was, so to speak, the second epoch in the history of ion—molecule studies. 

Reaction (102) has also been searched for in a tandem mass spectrometer [95] and a flowing afterglow experiment [164]. In both studies it was not observed, in agreement with the result of single source mass spectrometer experiments. These studies set the upper limits of the cross-section for reaction (102) at 6 x 10 cm (for He energies from 1 to 10 eV) and at 10" cm (for thermal energy reactions), respectively. 

This chapter deals with instrumentation and experimental methods to study gas-phase ion-molecule reactions, especially in relation to ion attachment with alkali metal ions. The obvious tools for this are mass spectrometers and tandem mass spectrometers. These are discussed in Sects. 4.3 and 4.4. Alternatively, gas-phase reactions may be studied in a variety of reaction chambers, either in static mode or in flow systems. Examples of the static reaction chambers are high-pressure MS devices (see Sect. 4.7). Examples of flow devices are flowing afterglow and drift-tube systems (see Sects. 4.5 and 4.6, respectively). However, next to these tools, there are a number of other tools that may be helpful. 

---