Metrohm 746 VA Trace Analyzer - Manual (Page 479)

6 Data processing and evaluation
746 VA Trace Analyzer / 747 VA Stand
6-16
The two base points dU.front and
dU.rear as well as the two slopes
S.front and S.rear can also be
entered manually instead of being
determined automatically.
expon., whole
dU.front dU.rear
S.rear
S.front
• Type = expon., Scope = f.double/r.double
This type of baseline is used for the evaluation of overlapping peaks; for the
1 st peak the type expon. , f.double must be used and for the 2 nd peak the
type expon. , r.double . The baseline is calculated in exactly the same man-
ner as for expon. , whole . With the previously determined peak base points
dU.front for the 1 st peak and dU.rear for the 2 nd peak as a basis, the two
associated slopes S.front and S.rear are used to calculate the exponen-
tial baseline.
The two base points
dU.front and dU.rear as
well as the two slopes
S.front and S.rear can
also be entered manually in-
stead of being determined
automatically.
expon., f.double
expon., r.double
With all peak-shaped curves not only the smoothed curve, but also the subtracted
curve subtracted in which the calculated baseline is subtracted from the
smoothed measured values (see the examples with Scope = whole ) can be shown.
This curve or its knee region can be used to assess the evaluation, but the following
cases must be distinguished:
Curve knee nicely
curved, base point
correctly selected
Curve knee too steep,
base point too near the
peak maximum
Undershooting, base
point too far removed
from the peak maxi-
mum
Subtracted
curve
Base point
(rear)
Base point
(front)