INFICON Explorer Portable Gas Chromatograph - Manual (Page 182)

Method Development
180
Sometimes a peak is discovered which trails off the falling edge of a much larger
peak. In this case dropping a perpendicular baseline would overestimate the area of
the second peak. To compensate for this, a simple baseline, directly connecting the
start and stop points of the second peak is used. The area beneath the baseline is
allocated to the preceding (or primary) peak. The method of drawing in the baseline
for the second peak is called a tangent skim. The criteria for skimming a peak are:
Equation 1: t1/t2 > 4
Equation 2: H1/H2 > 2
where t = the time between the peak maxima and the valley between the two peaks
and H = the height of the peak.
Setting Integration Parameters
To set the peak recognition factors:
1. Select Integration Method from the Analyzer menu.
The Integration Method dialog is displayed.
2. The Slope Up factor determines what the integration start point will be.
If Up Slope is set to 6 mV/S, then the integrator will look for the signal level to
rise at a rate of for 6 mV/S one sample and at least 3 mV/S for four samples.
Up Slope can be any value from 0.1 to 99 mV/S. Typically values between 0.5
and 5 mV/S are used.