User`s guide

Operation
105
Standard Injection—If your ATD/TD is equipped with the optional
Internal Standard Addition accessory (P/N M041-3657) you can
enable or disable the option from this tab. A standard can
automatically be introduced onto every sample tube prior to
desorption. The standard is added after the tube is purged.
If you have enabled this option, then you must enter a standard
injection time on the Timing tab (see the Standard Inject Time in the
Timing tab section above). The Internal Standard (IS) valve is
activated for the duration of the Standard Injection time to allow the
introduction of a volume of standard onto the sample tube. After the
end of the standard injection time, the IS valve is closed and the
ATD/TD will proceed with desorption of the tube.
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 100,000:1, enabling the ATD/TD to handle
sample concentrations ranging from part-per-trillion (ppt) to high
percentage levels.
You will use these commands to enable the split flows.
If you enable the Inlet and/or the Outlet Split options, you must set
the split flow rates using the Maintenance option on the Tools
menu. See Setting the GC Column Head Pressure on page 77 for
details on setting the flows rates. See Setting Sample Split Ratios on
page 228 for details on determining also the values of the split flow
rates.
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