User guide

Inlets 8
Advanced User Guide 227
The flow diagrams in the rest of this document show the septum
head in place with a separate drawing for the septumless head.
Heating the PTV inlet
The control parameters for PTV temperature programming are
the same as for the column oven, but are reached by pressing
[Front Inlet]. Temperature can be programmed with an initial
temperature and up to 3 rates and plateaus. Rates between 0.1
and 720 °C/min can be selected. See “Setting COC inlet
parameters” on page 225 for details.
At the end of the run and during post- run, the PTV is held at its
final temperature. This permits backflushing without
contaminating the inlet.
Additional temperature ramps
For most purposes, the PTV is designed to hold the sample in
the inlet liner until the entire sample—there could be several
injections—has been injected. Then the PTV is heated rapidly to
transfer the sample to the column. This can be accomplished
with an initial hold, a single ramp, and a hold at the end to
complete sample transfer.
Two additional ramps are available and have several possible
uses:
• The inlet can be heated to a high temperature to thermally
clean the liner for the next run.
• The inlet can be programmed downward—just set the Final
temp below the previous temperature—to reduce thermal
stress on the inlet.
Septum head
Septumless head
CAUTION
If the initial inlet temperature and the oven initial temperature are
too close, the inlet may be unable to maintain its setpoint. We
recommend a difference of at least 6 °C, either higher or lower.