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Ion Trap Mass Analysis

A typical ion trap, also called quadmpole ion trap or three-dimensional ion trap, consists of a cylindrical ring electrode to which a quadmpole RF field is applied, and two end-cap electrodes [60,61] (Fig. 4.4). The end-cap electrodes contain holes for the introduction of ions from an external ion source and for the ejection of ions out of the trap towards the external electron multiplier detector. The ion trajectories in the trap are stabilized by a He bath gas ( 1 mbar). With respect to ion trap actions, the individual steps in the mass analysis process are performed [Pg.93]

As the number of ions that can be stored in the trap is limited by space charge effects, software procedures have been developed to control the number of ions in the ion trap by varying the duration of the ion injection pulse from the external ion source with the ion current at the time [61], Too high numbers of ions in the ion trap will adversely influence mass resolution and accuracy. Ion ejection and subsequent detection can be achieved with unit-mass resolution, or at enhanced resolution by slowing down the scan rate. [Pg.94]

More recently, instruments with a hnear two-dimensional ion trap (LIT), i.e., a linear quadrupole as ion trap, have become commercial available [24, 62, 63]. As a LIT is less prone to space charging effects, a higher number of ions can be accumulated, and enhanced sensitivity can be achieved. Initially, LITs were apphed in hybrid Q-LIT [24] a LIT and hybrid LIT-FT-ICR-MS [64] instruments, but later on stand-alone versions of an LIT were introduced too, thus competing the three-dimensional ion traps. A dual-pressme two-stage LIT has been reported as well the first high-pressure ion trap serves to capture, select, and fragment ions, whereas the second low-pressure ion trap is used to perform fast scamiing of product ions, eventually at enhanced resolution [65]. [Pg.94]


An isolation width of 1.5 amu is typically employed for PL analysis because the ions tend to be fragile in ion trap mass analysis (26). In some cases, a width of 1 amu is employed to remove potential background interferences. [Pg.228]


See other pages where Ion Trap Mass Analysis is mentioned: [Pg.344]    [Pg.93]   


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