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Part 1. Electronic Pneumatic Control (EPC) Flow and Pressure Control
Enter the rest of the inlet parameters
Enter the rest of the inlet parameters
The split/splitless inlet has four operating modes:
• Split—The sample is divided between the column and a vent flow.
• Splitless—The sample is not divided. Most of it enters the column. A small
amount is purged from the inlet to avoid excessive peak broadening and
solvent tailing.
• Pulsed split—Similar to split, except that the inlet pressure is raised before
and during injection and returned to normal at a user-specified time. Total
flow is increased as well so that the split ratio does not change. This special
kind of “programming” is independent of the three-ramp flow or pressure
programming.
• Pulsed splitless—Like pulsed split, but splitless.
The split/splitless inlet has a gas saver feature. This reduces the flow of carrier
into the inlet and out the split vent after the injection is complete. It does not
alter the flow through the column.
The septum purge flow is set automatically on all EPC inlets.
And, of course, the inlet temperature can be controlled.
SUMMARY
Note that, except when setting the carrier gas type, we have been
concerned only with the Column tables. This is fundamental to successful
operation of the 6890 with EPC inlets.
FIRST: Set up the column
THEN: Set up the rest of the instrument
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