Metrohm 746 VA Trace Analyzer - Manual (Page 287)

5.6 Method Specifications
746 VA Trace Analyzer / 747 VA Stand
5-136
Parameter Range; Default value / Meaning
Baseline display only
Baseline
Title for those parameters which concern calculation of the baseline.
These parameters are not displayed for substances recorded with
measurement mode PSAMODE.
Type linear, polynom, expon., AC2 rel., AC2 abs.; linear
Baseline type
The following possibilities are available for approximation of the
baseline and the evaluation of peaks/waves (see also section 6.7):
linear Linear baseline with DPMODE, SQWMODE, AC1MODE,
DCTMODE (with SSWEEP):
The
linear type baseline is determined using the tangent
method. After definition of the peak base points dU.front
and dU.rear (automatically or by manual entry), starting
from the base points an iterative search within a fixed
range (inward: up to 1 point before the peak maximum;
outward: ca. 20 mV) is made for a common slope. The
two points of tangency are connected to produce the lin-
ear baseline.
If no common slope is found, the linear baseline is drawn
directly through the two base points.
linear, whole
dU.front dU.rear
Linear baseline with DCTMODE (with SWEEP):
Wave-shaped curves recorded with DCTMODE are al-
ways evaluated with the tangent method
Type = linear .
The base points dU.front and dU.rear and the associ-
ated slopes S.front and S.rear can be determined
automatically or entered manually. In contrast to peaks
with a linear baseline, the slopes may be different.
S.front
S.rear
U.wave
I.wave
dU.front dU.rear
linear, whole (DCT)
Point of tangency
(rear)
Point of tangency
(front)
Base point
(front)
Range for
tangent search
Range for
tangent search
Base point
(rear)
Base point
(rear)
Base point
(front)