Biology Reference
In-Depth Information
without scanning for different ions to acquire a complete mass spec-
trum. TOF-TOF instruments combine the quasi-simultaneous
detection of all ions in TOF
1
with high-energy CID MS/MS of
selected ions for PMF identification of proteins from genome
sequenced organisms [
57
]. High sequence coverage achieved by the
high dynamic range of TOF-MS (Table
1
), along with accurate mass
measurement coupled with sufficient resolution, makes it possible to
greatly restrict the number of false positives in protein database
searches. In addition, the high analytical speed and automation makes
MALDI-TOF-TOF MS suitable for large number of samples.
Despite the great sophistication of currently available configura-
tions, it is disappointing to note that there is no ideal mass spectrome-
try system capable of performing all applications required in proteomics
[
94
]. To complicate matters, the increasing trend of employing highly
automated mass spectrometry platforms in high-throughput
approaches is contributing to create numerous operators and users
who are unaware of the fundamentals of MS and for whom mass spec-
trometers are little more than black boxes able to produce thousands
of spectra per day in full computerized workflow. The objective pur-
sued by this chapter was to show that the basic operational principles of
mass spectrometry can be understood by a simple mathematical lan-
guage, and that this understanding is necessary to rationally utilizing
this versatile technique in its full potential. However, MS and MS/MS
spectra interpretation is outside the scope of this essay. The reader is
referred to several excellent monographs [
95
-
100
].
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