Metrohm 790 Personal IC - Manual (Page 146)

4.5 Chromatograms
790 Personal IC
137
Subtraction of a chromatogram
790 PERSONAL IC / Process / More / Subtract
This menu item opens the Subtract chromatogram window allowing the
subtraction of any opened chromatogram from the active, selected
chromatogram.
Select the chromatogram that should be subtracted, click on
and then on 790 PERSONAL IC / View / View all . The result is shown in the
active chromatogram window, which is considered as a new chroma-
togram and will be stored under a new name to avoid overwriting of old
data.
Data compression
790 PERSONAL IC / Process / More / Compress
Selection of this menu item opens the Raw data compression window for
compression of the raw data of the active chromatogram by summing
up several neighboring points.
Divisor Coefficient of compression (the number of data points is
reduced by this value). The default value of the compres-
sion coefficient is calculated so that the width at half-height
of the narrowest peak will be digitized by at least 30 points.
If the user enters a coefficient of compression that exceeds
the value offered by the software, integration precision may
decrease.
Invert chromatogram
790 PERSONAL IC / Process / More / Invert!
This menu item inverts the response curves for all channels of the
chromatogram so that negative peaks become positive and vice versa
(useful for chromatograms with wrong input polarity).