Metrohm 940 Professional IC Vario ONE/SeS/PP/Prep 3 - Manual (Page 111)

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5 Operation and maintenance
940 Professional IC Vario ONE/SeS/PP/Prep 3 (2.940.1530)
￭￭￭￭￭￭￭￭ 101
The SPM consists of three neutralization units, which are used in rotation,
regenerated with perchloric acid, and rinsed with ultrapure water. In order
to record every new chromatogram under comparable conditions, you
should normally work with a freshly regenerated SPM.
CAUTION
The SPM must never be switched over if liquid is not flowing through it,
since otherwise it may become jammed. If the SPM is in a dry state, it
must be rinsed for at least five minutes before it may be switched over.
CAUTION
The SPM has to be regenerated (see Chapter 5.17.2.1, page 101),
cleaned (see Chapter 5.17.2.2, page 102) or replaced (see Chapter
5.17.2.3, page 102) if the capacity of the SPM is reduced or if the
backpressure is high.
5.17.2 Servicing the SPM
5.17.2.1 Regenerating the SPM
If the neutralization units are loaded for a longer period with certain heavy
metals (e.g. iron) or organic impurities, these can no longer be completely
removed with the standard regeneration solution (100 mmol/L HClO
4
).
The capacity of the neutralization units and the detection sensitivity
decrease.
If such capacity problems occur at one or more positions, all neutralization
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.
Regenerate the SPM as described in chapter 5.12.3.2, page 90.