￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭
5 Operation and maintenance
942 Extension Module Vario ChS-PP (2.942.0300)
￭￭￭￭￭￭￭￭
35
5.3.3.1
Parts of the Metrohm Suppressor Module (MSM)
The SPM is made up of the same parts as the Metrohm Suppressor Mod-
ule (MSM).
1
2
3
4
5
Figure 11
Parts of the Metrohm Suppressor Module (MSM)
1
Union nut
2
Connecting piece
3
Rotor
4
Housing
5
Slot in the housing
5.3.3.2
Regenerating the anion suppression rotor
If the anion suppressor units are loaded with certain heavy metals (such as
iron) or organic contamination for long periods, then the standard regen-
eration solution may no longer be able to completely remove them. This
constantly reduces the capacity of the suppressor units, which results in
reduced phosphate sensitivity in mild cases and a large increase in the
baseline in severe cases.
If such capacity problems occur at one or more positions, all anion sup-
pressor units must be regenerated with one of the following solutions:
Regeneration solutions
￭
Contamination with heavy metals or elevated backpressure
:
1 mol/L H
2
SO
4
+ 0.1 mol/L oxalic acid
￭
Contamination with organic cationic complexing agents
:
0.1 mol/L H
2
SO
4
/
0.1 mol/L oxalic acid
/
acetone 5%
￭
Heavy contamination with organic substances
:
0.2 mol/L H
2
SO
4
/
acetone
≥
20%
￭
Contamination by certain environmental samples
1 mol/L H
3
PO
4