Mass analyzer features

Mass analyzer/ Feature Linear Quadrupole Quadrupole ion trap Linear time-of-flight Reflectron time-of-flight... 

Once the ions are formed in the ion source, they are accelerated towards the mass analyzer where separation according to their m/z ratio occurs. Before describing the main analyzers, it is better to consider one feature common to all of them the resolution. 

TABLE 2.2. A Rough Comparison of Some Features of the Mass Analyzers... 

Gunzer, F. Grotemeyer, J. New Features in the Mass Analyzed Threshold Ionization (MATl) Spectra of Alkyl Benzenes. Phys. Chem. Chem. Phys. 2002, 4, 5966-5972. 

TABLE 5 General Specifications and Features for Mass Analyzers Used in CE/CEC-MS ... 

In tandem MS mode, because the product ions are recorded with the same TOF mass analyzers as in full scan mode, the same high resolution and mass accuracy is obtained. Isolation of the precursor ion can be performed either at unit mass resolution or at 2-3 m/z units for multiply charged ions. Accurate mass measurements of the elemental composition of product ions greatly facilitate spectra interpretation and the main applications are peptide analysis and metabolite identification using electrospray iomzation [68]. In TOF mass analyzers accurate mass determination can be affected by various parameters such as (i) ion intensities, (ii) room temperature or (iii) detector dead time. Interestingly, the mass spectrum can be recalibrated post-acquisition using the mass of a known ion (lock mass). The lock mass can be a cluster ion in full scan mode or the residual precursor ion in the product ion mode. For LC-MS analysis a dual spray (LockSpray) source has been described, which allows the continuous introduction of a reference analyte into the mass spectrometer for improved accurate mass measurements [69]. The versatile precursor ion scan, another specific feature of the triple quadrupole, is maintained in the QqTOF instrument. However, in pre-... 

One critical feature of mass spectrometry when combined with chromatographic or electrophoretic separation techniques remains the duty cycle of the mass analyzer. A conventional LC chromatographic peak lasts about 10 s, which is sufficient to perform various MS and MS/MS experiments on various types of instruments. In the case of fast LC, the peak width can be in the range 1-2 s which is too fast for most mass analyzers except for TOF mass spectrometers. 

The ion microprobe mass analyzer s unique features permit three dimensional microanalysis of all elements in the periodic table and in... 

Hybrid Mass Spectrometer A tandem mass spectrometer comprised of multiple mass analyzers of different types. A Q-TOF is a hybrid, but a triple quadmpole is not. Ideally, a hybrid instrument harnesses the best features of each mass analyzer type to produce a system perhaps greater than the sum of the parts. 

The analytically important features of Fourier transform ion cyclotron resonance (FT/ICR) mass spectrometry (1) have recently been reviewed (2-9) ultrahigh mass resolution (>1,000,000 at m/z. < 200) with accurate mass measurement even 1n gas chromatography/mass spectrometry experiments sensitive detection of low-volatility samples due to 1,000-fold lower source pressure than in other mass spectrometers versatile Ion sources (electron impact (El), self-chemical ionization (self-Cl), laser desorption (LD), secondary ionization (e.g., Cs+-bombardment), fast atom bombardment (FAB), and plasma desorption (e.g., 252cf fission) trapped-ion capability for study of ion-molecule reaction connectivities, kinetics, equilibria, and energetics and mass spectrometry/mass spectrometry (MS/MS) with a single mass analyzer and dual collision chamber. 

Ions exiting the drift tube are mass analyzed in mass spectrometer MS2, an important feature if reactions are occurring in the drift cell. Ions are generally detected after MS2 by ion counting techniques. The mass spectrometers MSI and MS2 are typically quadrupole mass filters, and either one or the other can be run in RF-only mode for better signal but without mass selection, if desired. 

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