Metrohm 790 Personal IC - Manual (Page 105)

4 Operation
790 Personal IC
96
4.4.4 Integration
790 PERSONAL IC / Method / Integration
This menu item opens the Integration parameters window that contains
parameters and events for peak integration and consists of the follow-
ing two tabs:
Setup Integration parameters.
Events Integration events.
The «790 Personal IC» software includes a built-in automatic integration
algorithm to detect peaks on the chromatographic curve and to evalu-
ate them using calculated baselines. The integration procedure is tuned
by the integration parameters on the Setup tab and the integration
events on the Events tab. Integration events have higher priority than in-
tegration parameters. The integration can be modified manually using
the peak editor (see section 4.5.4).
The built-in integrator algorithm is based on the use of the first deriva-
tive (slope). In order to decide whether the slope at some point is sig-
nificant, 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 down slope differ.
The baseline and the start and end points are determined for each
peak. For separated peaks, the baseline consists of a straight line be-
tween the start point and the end point. For overlapping neighboring
peaks, a common baseline is normally constructed; this connects the
start point of the first peak with the end 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 base-
line. Alternatively, the baseline can also be drawn directly between the
valleys of the peaks with the event Enable valley-to-valley (see integration
events for baseline).
Single
peak
Peak apex
Merged peaks
Drop line Valley point Baseline Peak end Peak start