Calculation Of The Signal Value - Knauer Smartline 2300 Benutzerhandbuch

The Basic Principle of the RI Detector 2300/2400

Calculation of the Signal Value

Formula 2 Signal Value
The light beam reaches the two detector diodes 1 and 2 (see Fig. 3 on
page 6) which deliver the intensity values I
depending on the light beam's deflection. The results of the difference I
I and the sum I + I
2 1 2
menu SIGNAL.
The value of SIGNAL is calculated with the following formula:
(I
SIGNAL =
(I
formula 3
With I - I difference of intensity values
1 2
I + I sum of intensity values
1 2
a constant factor, defined by the function AUTOZERO
c constant factor, defined by the function CALIBRT
The signal result, indicated in the menu SIGNAL, is given out to the
device outputs. The signal value can theoretically be either positive or
negative.
The refractive index is highly temperature dependent. The change per
1 K for pure water is ~ 1x10
-4
5x10 RIU.
Refractive index detectors are very sensitive to changing the eluent
or it's composition. Therefore this detector type is not to be used for
gradient chromatography.
and I
1
are calculated continuously and indicated in the
- I )
1 2
+ a
*
+ I )
1 2
-4
RIU and for typical organic solvents is ~
during measurement,
2
c
7
-
1