wtw NitraLyt 700 IQ, Operating Manual, Page: 44 / 61

Calibration and measuring NitraLyt
®
700 IQ
4 - 24 ba75397d03 12/2004
The calibration procedures, 1 point standard (1) and 2 point stand. (3)
are carried out in standard solutions. Chloride does not interfere here.
An incorrectly set chloride compensation only affects the following
measurement.
Chloride compensation
for measurements
The function, Cl compens. , should always be used if the concentration
of the interfering ion causes the measurement signal to leave the range
of the required accuracy. To avoid calibration and measuring errors, we
recommend to
!
routinely determine the chloride content
!
switch on the Cl compens. function
!
enter the chloride content.
The more the actual chloride content deviates from the value entered
for the chloride compensation, the more the displayed measured value
deviates from the current nitrate content.
Fig. 4-7 shows the interrelationship of the real and displayed
NO3-N value for different chloride contents. The characteristic curve
with optimum chloride compensation corresponds to the characteristic
curve without chloride contents.
Fig. 4-7 Influence of chloride on the measured nitrate value
4.2.2 Further influences on the measured value
Greases, oils, certain tensides and similar substances can shorten the
operational lifetime of the NitraLyt
®
NHA/AT exchange electrode.
Therefore, they should not be present in the test sample.
c (NO3-N) [mg/l]
real
c (NO3-N) [mg/l]
angezeigt von NitraLyt 700 IQ
0 mg/l Cl
-
100 mg/l Cl
-
500 mg/l Cl
-
0,1 1 10
100 1000
0,1
10
100
1000
1