Page 41 - Application Handbook - TOC

SCA-130-307

■ Interferences 40
In addition to CO 2 formed from the organic
30
components, various nitrogen oxides are
formed during the combustion of ammonium 20
salts or ammonia water. Excessively high Signal[mV]
nitrogen levels can lead to the formation of 10
significant amounts of N 2O (nitrous oxide).
0
Nitrous oxide exhibits absorption bands in the -4
same IR detection range as CO 2 and can, 0 7 14
Zeit[min]
therefore, be misinterpreted for CO 2. In
addition, nitrous oxide can cause tailing and Fig. Example peaks of 40% ammonium nitrate
can affect the peak symmetry. solution
A B-type scrubber is used to eliminate
possible interference by nitrous oxide. Due to
the high solubility of N 2O in water, the gas is
dissolved in the B-type scrubber and will not
reach the detector.

■ Results
The duplicate determination of the
ammonium nitrate solution yielded the
following results:

■ Recommended analyzer / Configuration
Probe NPOC RSD TOC-L CPH
[mg/l] [%] OCT-L (8-port sampler)
Ammonium
B-Type- Scrubber
nitrate solution 56,5 0,8
(40%)
Ammonium
nitrate solution 56,7 1,2
(40%)