Function and design
multi N/C 2100S (duo, pharma)
28
3.3
Function and measuring principle
The analyzer is a compact, high-performance device for determination of the content of
organic bound carbon and/or the total nitrogen content in aqueous samples.
Halogen
trap
NDIR
detector
NO
detector
Flowmeter
PC
Controls
display
Data printout
Data export/
import
Water traps
Phosphoric
acid pump
Condensate
pump
TIC condensate
container
Dryer
Combustion
furnace
Waste
Figure 18Principle of operation
The samples are digested at high temperatures in the presence of special catalysts. This
allows even very stable and complex carbon and nitrogen compounds to be converted
quantitatively.
The sample aliquot is dosed directly into the hot zone of the filled reactor (combustion
tube). Here, the pyrolysis and oxidation of the sample in the carrier gas flow is per-
formed with the aid of the catalyst. The carrier gas is also used as an oxidizing agent.
R + O
2
→ CO
2
+ H
2
O (1)
R-N+ O
2
→ NO + CO
2
+ H
2
O (2)
R-Cl+ O
2
→ HCl + CO
2
+ H
2
O (3)
R - carbonic substance
The measuring gas is cooled in the condensation coil and condensed water is separated
from the measuring gas in the subsequent TIC condensate container. After further dry-
ing and removal of corrosive gases, the CO
2
measuring gas is added to the NDIR detector
or NO detector.
Inorganic carbon is detected by injecting a sample aliquot into the acidic TIC reactor and
driving out the formed CO
2
via the NDIR detector.
