
Chapter 5 Optimizing Instrument Settings
5-64 PerSeptive Biosystems
5
Effects of mass
and matrix
Note the following:
• At a fixed Delay Time, higher masses require a lower Grid
Voltage%. See Appendix E, Grid Voltage% and Delay
Time Settings, for a graphic representation of the
relationship between mass, Grid Voltage%, and Delay
Time.
• At a fixed Grid Voltage%, higher masses require a higher
Delay Time. See Appendix E, Grid Voltage% and Delay
Time Settings, for a graphic representation of the
relationship between mass, Grid Voltage%, and Delay
Time.
• Optimum tuning of Delay Time and Grid Voltage% is
slightly dependent on matrix due to the different initial
velocities associated with different matrices. The
optimum Delay Time may be different, within 100 nsec at
the same Grid Voltage%, for the same sample in different
matrices.
NOTE: The Grid Voltage% setting in Reflector mode is
typically significantly lower than the setting in Linear mode
for the same mass range. For example, if Grid Voltage% in
Linear mode is 94%, Grid Voltage% in Reflector mode may
be 70%. (These values are used as an example they may
not be optimal for your system.)
Readjusting the
laser after
optimization
After you have optimized Guide Wire Voltage%, Delay Time,
and Grid Voltage for optimum resolution, you can further
fine-tune by adjusting the laser intensity. For information on
adjusting the laser intensity, see “Adjusting laser intensity” on
page 5-58.
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