Metrohm 940 Professional IC Vario ONE/ChS/LPG - Manual (Page 90)

5.12 Suppressor
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940 Professional IC Vario ONE/ChS/LPG (2.940.1250)
5.12.3.2 Regenerating the suppression rotor
If the suppressor units are loaded with certain heavy metals (such as iron)
or organic contamination for long periods, then the standard regeneration
solution may no longer be able to completely remove them. This con-
stantly 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 suppressor
units must be regenerated with one of the following solutions:
￭ Contamination with heavy metals:
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%
CAUTION
Pump tubing made of PVC must not be used for solutions containing
organic solvents.
We recommend using the high-pressure pump for regeneration.
Regenerating the suppressor
1 Disconnecting the suppressor from the IC system
￭ Disconnect the capillaries of the suppressor labeled regenerant
and rinsing solution from the IC system.
2 Regenerating the suppressor
Regenerate the three suppressor units one after the other for approx.
15 minutes using one of the solutions mentioned above.
￭ Connect the capillary labeled regenerant to the outlet of the
high-pressure pump using a coupling (6.2744.040).
￭ Set the flow of the high-pressure pump to 0.5 mL/min in the soft-
ware.
￭ Switch on the high-pressure pump.
If the pressure decreases during regeneration, slowly increase the
flow of the pump to a maximum of 2 mL/min. When doing so,
make sure that the pressure does not exceed 2 MPa!
￭ After approx. 15 minutes, switch off the high-pressure pump.