Tandem MS with FT-ICR Instruments - Part

As ion trapping devices, FT-ICR instruments belong to the tandem-in-time category of instruments. The stage of precursor ion selection (MSI) is accomplished by selectively storing the ions of interest, whereas all others are ejected by means of a suitably tailored excitation pulse. For this purpose, the SWIFT technique [124] or correlated sweep excitation (CHEF) [125,126] are used (Chap. 4.7.7). Both methods generate tailored waveforms that cause excitation of all but the selected ions. Like QITs and LITs, FT-ICR analyzers are also capable of MS . 

Although hybrid designs such as Qh-FT-ICR or LIT-FT-ICR are prevalent in modem FT-ICR instmmentation (Chaps. 4.7.11 and 4.9.1), there is still the need for tandem MS experiments inside the ICR cell. Its dedicated abilities of very precise precursor ion selection, elongated ion storage in the order of tens of seconds, and possibility to admit gaseous reactants to perform even slow ion-molecule reactions make the ICR cell a unique tool [3]. 

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