INFICON Explorer Portable Gas Chromatograph - Manual (Page 299)

Explorer Operator Manual
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2. Delete unwanted compounds from the Column C library.
3. Save the custom assay under a new name.
4. Send the new assay to Explorer.
You will have the 3 target compounds in the library.
Since developing this method did not involve changing any of the critical
method parameters such as pressure, temperature or injection time the existing
calibration information should still result in peak identification when you run
these compounds.
5. Run an analysis and calibrate the library compounds, as discussed in
Calibration on page 215.
Solution 2 - Two Runs with Analysis Time = 8 minutes
If the 13 minute analysis time is too long, then we can optimize the method for
minimum analysis time, noting that:
Benzene on Column A is well separated from the other compounds of interest.
Vinyl chloride and chloromethane are only separated on Column C, so these
compounds must be run on Column C.
This new method will consist of two runs. The first analysis on Column A will
separate benzene from the light compounds. We will then do another run to separate
the light compounds on Column C. Benzene will be backflushed off the precolumn
(Column A) to minimize the analysis time.
Benzene elutes at about 102 seconds on Column A. The backflush time will be set to
approximately 150 seconds for the first run on Column A, this allows a little extra
time to ensure the entire benzene peak has cleared the column. To set the analysis
time, multiply the backflush time by a factor of 2.2, this allows time for any
compounds eluting after benzene to be backflushed out of Column A.
The total analysis time for the first run will be 150 s x 2.2 = 330 s ~ 6 minutes.