Metrohm 853 IC CO2 Suppressor - Manual (Page 7)

1.1 Instrument description
853 CO
2
Suppressor / Instructions for Use 8.853.8001EN
1
1 Introduction
1.1 Instrument description
The 853 CO
2
Suppressor is used to remove CO
2
before detection
takes place. CO
2
can enter the eluent flow from the sample itself, or is
produced by the suppressor reaction (see below, Reaction in the sup-
pressor module «MSM II»).
If the 853 CO
2
Suppressors is connected between the suppressor mo-
dule «MSM II» and the detector block the CO
2
peak is effectively mini-
mized. The principle is based on the permeability of the Teflon AF TM
membrane in the degassing cell of the 853 CO
2
Suppressor to gases.
The eluent (together with the injected sample) passes through a capil-
lary with a Teflon AF TM membrane contained in the degassing cell, in
which a vacuum has been created by a pump. At the same time the
pump draws CO
2
-free air (the CO
2
is removed by the CO
2
Absorber
Cartridge) through the degassing cell. The lower CO
2
vapor pressure in
the degassing cell compared with that in the capillary results in the dif-
fusion of CO
2
from the eluent flow. The pump of the 853 CO
2
Suppres-
sors is provided with electricity from an external power supply. The 853
CO
2
Suppressor is controlled by Remote commands.
Reaction in the suppressor module «MSM II»
If a carbonate eluent is used then the following reaction (among others)
takes place in the suppressor module «MSM II»:
R-SO
3
- H + + NaHCO
3
/Na
2
CO
3
→ R-SO
3
- Na + + H
2
O + CO
2