Advantages of FTMS

Advantages of FTMS for Screening Ligands for Protein Binding... 

Another advantage of FTMS for MS/MS experiments is that high resolution daughter ion spectra can be obtained. Using a single cell and narrow band (heterodyne) (7, 17) detection, daughter ion... 

To exploit the advantages of FTMS fully we have implemented several predefined ejection, activation and acceleration options, like single shots, covers, sweeps over some mass window, sweeps around some unaccelerated mass window, tickling belts with phase inversion, parent ion selection chirps, activation shots for daughter ion production, etc. 

The high sensitivity of FTMS can be used to great advantage. 

Although both hybrid LTQ-FTMS instruments find applications in the dmg metabolism area, the LTQ-Qrbitrap, with its simplified maintenance, lower cost, and in most cases better sensitivity at low masses, is generally more applicable to small-molecule analysis. The LTQ-FTICR, with the advantage of higher resolution and mass accuracy, covers a wider range of applications, from small molecules to peptides and proteins, where most advantages are found in the analysis of large biomolecules. 

Time-of-flight (TOF) MS detectors (Fig. 15.7) are commonly used in pro-teomics studies of proteins and protein fragments because this type of detector can handle and analyze very large molecular and fragmentation ions. Fourier transform mass spectrometers (FTMS) are being incorporated into commercial LC/MS systems and offer the advantage of being nondestructive detectors that can trap and repeatedly analyze the same sample in order... 

Selected topics in Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry instrumentation are discussed in depth, and numerous analytical application examples are given. In particular, optimization ofthe single-cell FTMS design and some of its analytical applications, like pulsed-valve Cl and CID, static SIMS, and ion clustering reactions are described. Magnet requirements and the software used in advanced FTICR mass spectrometers are considered. Implementation and advantages of an external differentially-pumped ion source for LD, GC/MS, liquid SIMS, FAB and LC/MS are discussed in detail, and an attempt is made to anticipate future developments in FTMS instrumentation. 

Recently, low pressure Cl and SCI experiments, which take advantage of the long reaction times (typically 10 to 60 seconds) possible in an FTMS, have been demonstrated (9). Figure 4 exhibits low-pressure El and DCI spectra of Riboflavin (Vitamin B2), taken without a pulsed valve. Only the DCI spectrum taken at 2x10"8 mbar contains the quasi-molecular ion at M = 377. 

Finally, Equation 1 exhibits another important advantage of high fields in FTMS. Both the maximum trapping time and the maximum number of collisions (and gas-phase reactions) increase quadratically with B. Consequently increased magnetic field strength offers experimental access to larger ion clusters (Figure 2). 

In this review we discuss five techniques involving Fourier transform mass spectrometry (FTMS) for determining qualitative and quantitative metal ion-ligand bond energies. These include (i) exothermic ion-molecule reactions, (ii) equilibrium measurements, (iii) competitive collision-induced dissociation, (iv) endothermic ion-molecule reactions, and (v) photodissociation. A key advantage of the FTMS methodology is its ion and neutral manipulation capabilities which permit the formation and study of a limitless number of interesting metal-ion systems. 

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