Setting Coc Inlet Flows/Pressures - Agilent Technologies 7890 Series Advanced Operation Manual

3
Inlets

Setting COC inlet flows/pressures

94
Track oven mode
In the Track oven mode, the inlet temperature stays 3 °C
higher than the oven temperature throughout the oven
program. You cannot enter a temperature setpoint—it is set
automatically. If you have CryoBlast, the inlet will track oven
temperatures to –40°C; without CryoBlast, the lower limit is
set by room temperature.
Temperature programming mode
In this mode, you can enter up to three temperature ramps
in the inlet parameter list so that the inlet and the oven
operate independently. This is the recommended mode if
operating below –20 °C.
At these very low oven temperatures, the inlet temperature
should be at least 20 °C higher than the oven temperature.
This will be more than adequate for solvent focusing.
At temperatures greater than ambient, the inlet should
always be at least 3 °C warmer than the oven for proper
control of the inlet temperature.
The oven temperature program controls the run. If it is
longer than the inlet temperature program, the inlet will
remain at its final temperature until the oven program (and
the run) ends.
Cryogenic considerations
When using track oven mode with a cryogenic oven, all other
inlets must be off or in track oven mode.
If cryo is turned on, and if the inlet is cooled during a run,
cryogen is used to achieve the setpoint. This may have a
negative impact on the chromatographic performance of the
oven and cause distorted peaks.
The inlet uses the same cryo coolant as configured for the
oven.
1 Configure capillary column to inlet—select constant flow
or pressure.
Set column flow, linear velocity, or inlet pressure.
2
Set Septum Purge, typically 3 to 10 mL/min.
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Advanced Operation Manual