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Introduction
What Types of Experiments Can I Perform with the LTQ XL MS Detector?
Thermo Electron Corporation
LTQ XL Getting Started
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First, with either depth or breadth focus, the LTQ XL MS detector scans for
parent ions (MS) over the specified mass range. The most intense ion of the
MS spectrum is selected for fragmentation (MS/MS).
• Second, if you chose the depth focus, after the most intense ion of the
MS spectrum is fragmented—producing an MS/MS spectrum—the
LTQ XL MS detector selects and fragments the most intense ion of the
MS/MS
spectrum. This results in an MS3 spectrum, the level specified
as the maximum depth for this example. The LTQ XL MS detector then
backs up one level and fragments the second most intense ion of the
MS/MS
spectrum, creating more product ions on the level of MS3 from
this parent ion. This process is then repeated for the second most intense
ion in the
MS
spectrum.
• If you chose the breadth focus, after the most intense ion of the MS
spectrum is fragmented—producing an MS/MS spectrum—the LTQ
XL MS detector selects and fragments the second-most intense ion of
the
same
MS spectrum. The fragmentation of parent ions continues to
the
Max Breadth
level that you specified (2, for this example). After the
two most intense peaks on the MS level are fragmented, the LTQ XL
MS detector scans the first
MS/MS
spectrum to select and fragment the
two most intense ions. This results in product ions on the level of MS3,
the level specified as the maximum depth for this example. This process
is then repeated for the second most intense ion in the
MS
spectrum.
The results of a Data-Dependent Ion Tree experiment can be viewed in the
Xcalibur Qual Browser window. The results are displayed as a structure tree
that originates from a particular parent ion.
