Metrohm IC Net 2.0 - Manual (Page 119)

7.4 Integration
IC Net 2.0 111
7.4 Integration
7.4.1 General information
IC NET / Method / Integration
This menu item opens the Integration parameters window which
contains parameters and events for peak integration and consists
of the two tabs Setup (see section 7.4.2) and Events (see section
7.4.3).
The «IC Net» software includes a built-in automatic integration al-
gorithm to detect peaks on the chromatographic curve and to
evaluate them using calculated baselines. The integration proce-
dure is tuned by the integration parameters on the Setup tab and
the integration events on the Events tab. Integration events have
higher priority than integration parameters. The integration can be
modified manually using the peak editor (see section 8.4).
The built-in integrator algorithm is based on the use of the first
derivative (slope). In order to decide whether the slope at some
point is significant, the first derivative value is divided by the
baseline noise and the result is compared with a threshold value
called
Slope
. The threshold values for the upslope and downslope
differ.
The baseline and the starting and finishing points are determined
for each peak. For separated peaks the baseline consists of a
straight line between the starting point and the finishing point. For
neighboring peaks which overlap a common baseline is normally
constructed; this connects the starting point of the first peak with
the finishing point of the last peak. The peaks are separated from
one another by dropping a perpendicular line from the lowest
point (valley) between the peaks to the common baseline. Alter-
natively the baseline can also be drawn directly between the val-
leys of the peaks with the event Enable valley-to-valley (see inte-
gration events for baseline).
Peak
apex
Single
peak
Merged peaks
Drop line Valley point Baseline Peak end Peak start