ISQ User Guide - Write Frame of Mind

4 Creating a Method
h. In the Groups pane, review the information in each row. As you create scans in the
Scans pane, information in the groups pane is automatically displayed.
Note If some of the columns mentioned below are not shown in the Method Setup pane,
you can right-click on a heading and display them. You can also reorganize the columns by
clicking on the heading of a column and dragging it to the left or right.
• The Time column is used to set the time that the ISQ begins to acquire data after
the GC starts. It is typical to have enough of a time delay to allow the solvent to
get through the column before starting acquisition.
All of these scans use the last tune file that was created. You can also use a specific
tune file for each of the scans.
• The Total Scan Time column indicates the sum of all the scans in each segment.
The total scan time also contains the stabilization time that occurs between each
scan. In this method, beginning 2.5 minutes into the GC run, you will get a
complete set of scans every 0.816 seconds. At 4 minutes into the GC run, the
scanning has completely changed.Now the scans will repeat every 0.412 seconds
until the GC run is complete.
• The Chrom Filter On column is used to enable the chromatographic filter. This
filter smoothes spectral data as it is acquired, which may increase the
signal-to-noise ratio by a factor of 2 or more. The chromatographic filter is most
useful when at least four full scans are acquired across a GC peak. This setting is
typically left on.
• The Chrom Filter Peak Width column is used to set the peak width to match
the width of the GC peak (in seconds). If the peak width is set too large, signal
intensity may be reduced. The default value is 1 s.
38 ISQ User Guide Thermo Scientific