Metrohm 2.942.0500, Manual, Page: 36 / 63

3.6 Metrohm CO
2
Suppressor (MCS)
￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭
28
￭￭￭￭￭￭￭￭
942 Extension Module Vario SeS/PP (2.942.0500)
1 Prepare a tubing cartridge of the peristaltic pump for the regenera-
tion solution
(see chapter 3.4.1, page 15) .
2 Connect the capillary labeled rinsing solution to the outlet of the
pump tubing using a pressure screw (6.2744.070).
3 Connect the PTFE capillary from the rinsing solution bottle to the inlet
of the pump tubing.
3.6 Metrohm CO
2
Suppressor (MCS)
3.6.1 General information on the MCS
NOTICE
The Metrohm CO
2
Suppressor (MCS) is used only in conjunction with
conductivity detection with chemical suppression.
The Metrohm CO
2
Suppressor (MCS) removes the CO
2
from the eluent
stream. This lowers the background conductivity, improves detection sen-
sitivity and minimizes the injection peak and carbonate peak.
CO
2
can enter the eluent stream through the sample itself or can develop
due to the suppression reaction in the suppressor. Connecting the MCS
between the suppressor and detector minimizes the carbonate peak in the
chromatogram.
The MCS essentially consists of a degassing cell containing a capillary
made from a fluoropolymer membrane. The capillary is permeable to
gases. The degassing cell is connected to the vacuum pump. In the
degassing cell, the eluent is directed through the capillary made of a fluo-
ropolymer membrane. At the same time, the vacuum pump generates a
vacuum and draws in the air from the outside. The pressure and concen-
tration difference this creates in the degassing cell relative to inside the
capillary causes the CO
2
to be diffused out of the eluent stream. The
ambient air is drawn in by a CO
2
adsorption cartridge to filter out the CO
2
from the air.