Micro Gc Cycle With Ramped Pressure - Agilent Technologies 990 User Manual

2 Instrument Overview

Micro GC Cycle with Ramped Pressure

Micro GC Cycle with Ramped Pressure

The timing diagram below provides an overview of the ramped (programmed) pressure cycle of
the Micro GC. The timing before the injection is identical to the constant pressure cycle.
1
The pressure rise is started,
the duration is depending
on two parameters:
• Pressure rise
• Final pressure
Final
pressure
Ready
Initial
pressure
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method time
Equilibration
time
Run started
2
During initial time,
the column head
pressure remains
the same.
Agilent 990 Micro GC User Manual
The remaining final time depends on the total run time, the
duration of the initial time and the pressure rise. This means that
it is possible that the final time is zero. Another situation is that
the final pressure is limited because of these settings. The
software will check all parameter values and change them into
realistic values.
Note: During the run time, there can be only one pressure ramp to
a higher pressure.
Pressurization Inject time
time
Inject Start data
acquisition
3
As soon as the final
pressure is reached,
the rise stops and
the final time
begins. The
pressure remains
the same.
Not ready
1
Pressure
rise
Initial Rise time Final time
time
3
2
Run time
4
Relieve time, the
time needed to
decrease the
column head
pressure from the
final pressure to
the initial
pressure.
Pressure
release
Ready
Time
Relieve
Stabilization
time
time
4 5
Run
finished
5
Stabilization
time for the
pressure after it
has been
returned to the
initial pressure.
Fixed at 500 mS.
31