31
The
Precursor Ion
is usually an intense ion in the full scan mass spectrum.
Usually, the
Isolation Window
is the parent ion mass
±
1.0 (3.0 mass units
wide).
Waveform Type
is either Resonant or Non-resonant. The
Excitation
Storage Level
is the lowest mass stored during collision-assisted dissociation. A
good value can be calculated using the
“q” Calculator
at the bottom of the
window. The “q” Calculator sets arbitrary limits to the Excitation Storage Level so
you should be aware that it may calculate a value of 300 when the Precursor Ion
m/z is large. The excitation amplitude needed to dissociate the precursor ion
must be determined experimentally; e.g., using several runs with different ranges
of excitation amplitudes. Using the AMD (Automated Method Development)
mode is the easiest way to determine this voltage. The
Product Ion Mass
range
during method development encompasses the range from
Excitation Storage
Level
to the
Precursor Ion
mass. For more detail on MS/MS methods, seethe
Tandem Mass Spectrometry section in the 4000 GC/MS Software Operation
Manual.
Viewing Method Parameters in Manual Control
After a method is created in Method Builder, it can be previewed in Manual
Control. All MS parameters can be edited and previewed before a run. However,
the number of segments, or the start and end times of existing segments, can
only be changed in Method Builder.
Activating a Method
To activate a different method, do the following:
1. Click
the
File
menu.
2. Click
Activate Method
.
3. Select a method by doing one of the following:
•
Click
Recent Files
to display the eight most recent methods.
•
Click
Open
after selecting a method from a folder.
Summary of Contents for 4000 MS
Page 2: ......
