Waters Xevo TQ MS, Руководство оператора и по техническому обслуживанию, Страница: 30 / 184

1-14 Waters Xevo TQ MS Overview
Typical application
You typically use MRM mode to quantify known analytes in complex samples:
• Drug metabolite studies.
• Forensic or toxicology, for example, screening for target drugs in sport.
MRM mode does not produce a spectrum because only one transition is
monitored at a time. As in SIR mode, a chromatogram is produced.
Constant neutral loss mode
Constant neutral loss mode detects the loss of a specific neutral fragment or
functional group from an unspecified precursor(s).
The scans of MS1 and MS2 are synchronized. When MS1 transmits a specific
precursor ion, MS2 “looks” to see whether that precursor loses a fragment of a
certain mass. If it does, the loss registers at the detector.
In constant neutral loss mode, the spectrum shows the masses of all
precursors that actually lost a fragment of a certain mass.
Constant neutral loss mode
Typical application
You typically use constant neutral loss mode to screen mixtures for a specific
class of compound that is characterized by a common fragmentation pathway,
indicating the presence of compounds containing a common functional group.
ScanWave daughter scan mode
This mode is very similar to conventional product ion mode in that you can
specify an ion of interest for fragmentation in the collision cell, thus yielding
MS1
Scanning
(synchronized with MS2)
Collision cell
Pass all masses
MS2
Scanning
(synchronized with MS1)