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Introduction
Why Use the LTQ XL MS Detector?
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LTQ XL Getting Started
Thermo Electron Corporation
Why Use the LTQ XL
MS Detector?
The attribute that sets the LTQ XL MS detector apart from other LC
detectors is the high level of analytical specificity that it provides. The LTQ
XL MS detector can provide multiple levels of analysis. Each level of analysis
adds a new dimension of specificity for positive compound identification.
The various levels of analysis are as follows:
• Chromatographic separation and compound detection (non MS
technique utilizing chromatographic retention time)
• Mass analysis (molecular mass information)
• Two-stage mass analysis, MS/MS (structural information)
• Multiple MS-MS mass analysis, MS
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(structural information)
• ZoomScan™ analysis (charge state information)
Chromatographic separation and compound detection can be obtained by
all LC/detector systems. Retention time alone, however, does not positively
identify a compound because many compounds can have the same retention
time under the same experimental conditions. In addition, even if a
compound is identified correctly by retention time, quantitation results can
be in error because other compounds in the sample might co-elute with the
compound of interest.
Single stage mass analysis allows for the identification of analytes of interest.
Atmospheric pressure ionization typically produces mass spectra that
provide molecular mass information.
Two-stage mass analysis allows for even more positive compound
identification. MS/MS analysis monitors how a parent ion fragments when
exposed to an additional stage of ionization. There are two types of MS/MS
analysis: Full Scan MS/MS and Selective Reaction Monitoring (SRM). Full
Scan MS/MS monitors the production of all product ion from a specific
parent ion. SRM MS/MS analysis monitors a specific reaction path: the
production of a specific product ion from a specific parent ion. Using
MS/MS analysis, you can easily quantitate target analytes in complex
matrices such as plant or animal tissue, plasma, urine, groundwater, or soil.
Because of the specificity of MS/MS measurements and the ability to
eliminate interferences by an initial mass selection stage, quantitative target
compound analysis is easily accomplished using the LTQ XL MS detector.
Multiple MS/MS mass analysis provides a unique capability to obtain
structural information that can be useful in structure elucidation of
metabolites, natural products, and sugars. MS
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techniques on the LTQ XL
MS detector allow for stepwise fragmentation pathways, making
interpretation of MS
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spectra relatively straightforward. The LTQ XL MS