Tandem mass spectrometry advantages

The main advantages of the ms/ms systems are related to the sensitivity and selectivity they provide. Two mass analyzers in tandem significantly enhance selectivity. Thus samples in very complex matrices can be characterized quickly with Htde or no sample clean-up. Direct introduction of samples such as coca leaves or urine into an ms or even a gc/lc/ms system requires a clean-up step that is not needed in tandem mass spectrometry (28,29). Adding the sensitivity of the electron multiplier to this type of selectivity makes ms/ms a powerhil analytical tool, indeed. It should be noted that introduction of very complex materials increases the frequency of ion source cleaning compared to single-stage instmments where sample clean-up is done first. 

MS detection does not necessarily require as highly resolved GC separations as in the case of selective detectors because the likelihood of an overlapping mass spectral peak among pesticides with the same retention time is less than the likelihood of an overlapping peak from the same element. Unfortunately, this advantage cannot always be optimized because SIM and current gas chromatography/tandem mass spectrometry (GC/MS/MS) methods, it is difficult to devise sequential SIM or MS/MS retention time windows to achieve fast GC separations for approximately > 50 analytes in a single method. 

Tandem mass spectrometry is the ultimate problemsolving tool for chemical analysis when enhanced specificity, specificity, selectivity, sensitivity, and/or speed are required, but at a price. This is primarily due to the capacity of MS/MS to obtain spectra of selected precursor ions in complex mixtures. Advantages in using MS/MS are ... 

The major advantage of the tandem mass spectrometry approach compared to MALDI peptide fingerprinting, is that the sequence information obtained from the peptides is more specific for the identification of a protein than simply determining the mass of the peptides. This permits a search of expressed sequence tag nucleotide databases to discover new human genes based upon identification of the protein. This is a useful approach because, by definition, the genes identified actually express a protein. 

Flow injection analysis—mass and tandem mass spectrometry in the analysis of surfactants—advantages and disadvantages 123 Horst Fr. Schroder... 

As a consequence, for unequivocal identification of the constituents of complex mixtures found in surfactant blends and also in the analyses of surfactants and their metabolites in environmental samples, MS and tandem mass spectrometry (MS-MS) have proved to be more advantageous and are discussed thoroughly in Chapter 2. To optimise the output of reliable results and to save manpower and time certain procedures in sample preconcentration, clean-up and separation prior to MS examinations are inevitable. These are discussed in the present book in more detail in Chapter 3. 

SPECTROMETRY—II. FLOW INJECTION ANALYSIS—MASS AND TANDEM MASS SPECTROMETRY IN THE ANALYSIS OF SURFACTANTS—ADVANTAGES AND DISADVANTAGES... 

The TOF mass analyzer has a low duty cycle, and the combination with an ion accumulation device such as an ion trap is therefore very advantageous. It offers also MS capabilities with accurate mass measurement. In all acquisition modes, the ions are accelerated into the time of flight for mass analysis. Various other hybrid mass spectrometers with TOF have been described, including quadrupole ion trap [70] and linear ion trap [58]. High energy tandem mass spectrometry can be performed on TOF-TOF mass spectrometers [71, 72]. 

Another advantage of the use of tandem mass spectrometry is the ability to isolate a particular ion such as the molecular ion of the... 

In subsection 7.2.1, it was discussed that the neutral clusters generated from the beam source have a wide range of cluster sizes. Although there is no single, easily available technique which allows the size specific detection of neutral clusters, it is now well accepted that the cluster size distribution can be manipulated, to a certain extent, by careful control of the various experimental parameters. Mass spectrometric detection of clusters in general and tandem mass spectrometry in particular offer the inherent advantage of enabling size specific studies of the cluster ions. 

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