Setting Coc Inlet Flows/Pressures - Agilent Technologies 7820A Advanced User's Manual

Setting COC inlet flows/pressures

Advanced User Guide
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.
Configure capillary column to inlet—select constant flow or
1
pressure.
Set column flow, linear velocity, or inlet pressure.
2
Set Septum Purge, typically 3 to 10 mL/min.
3
3
Inlets
45