User`s guide

Operation
146
Inlet Split and Outlet Split Options—Two split points are
provided on the ATD/TD: one before and one after the cold trap. By
using either one, or both together, it is possible to set split ratios
ranging from zero to 200,000:1, enabling the ATD/TD to handle
sample concentrations ranging from part-per-trillion (ppt) to high
percentage levels.
For models operating with the PPC carrier gas control, you will use
these check boxes to enable the split flows. The actual flow values
can be entered on the PNU tab.
The Split Mode is selected by the drop down menu on the Option
tab. With Flow selected, the column flow selected on the PNU tab
can be Pressure or Flow Mode. The Inlet and Outlet Split flow
values are entered by the user. Values from 0 to 200 mL/Min are
allowable. With Ratio selected, the column flow selected on the
PNU tab must be in Flow Mode. The Inlet and Outlet Split ratio is
entered by the user. The maximum allowable ratio is a function of
the column flow selected. Values up to 500:1 are allowable for
column flows of 0.4 mL/min or less. For higher column flow values,
the ratio can be calculated by the following formula;
As the value of the Outlet Split is changed, the “% Injected” value
will be displayed at the bottom right of the Status screen.
Ratio = 200 mL/Min / Column Flow mL/Min
You will use these commands to enable the split flows.
Number of Injections—This parameter specifies the number of
injections (desorptions) per sample tube.
Single Tube—If you enter 99 the first selected tube will be loaded
and will continue to go through the desorption cycle repeatedly, until
you press Stop.
Sequence—If for any of the methods in the sequence a value of 99 is
entered for injections per tube, the sampling will be continuous. any
number entered from 1 to 98 will do that many injections.
Purge—When this button is pressed a popup menu appears. You
will be able to set the dry and heated purge temperatures. Dry Purge
is when the sample is purged of residual air at ambient temperature.