INFICON Explorer Portable Gas Chromatograph - Manual (Page 282)

Assay 1 User Notes
280
Compound Separation
Separation of the 40 compounds is accomplished in three separate runs in which the
heavy, mid-range, and light compounds of the sample are directed to Columns A, B,
C, respectively, for analysis.
The heavy compounds are analyzed on Column A. Any lighter compounds present
in the sample are not well separated and elute as an early series of peaks. The
integration delay can be used to prevent these peaks from being included in the peak
report and from being identified in the chromatogram. See Figure 19 and Figure 20.
For a run on Column A, the analytical column is also the precolumn. Backflush can
only begin after the last compound of interest elutes. The system must then
backflush, for a time slightly greater than the retention time of the last compound of
interest. The resulting analysis time should be approximately twice the backflush
time.
The maximum Explorer analysis time is 3200 seconds. If any heavy
compounds have not been backflushed from Column A by this time, it may be
necessary to delay the start of the next analysis until the necessary time has
elapsed (2 x backflush time).
Figure 19 Column A Compounds on the PID