Metrohm Inline Dialysis - Manual (Page 22)

4.1 Operation
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IC equipment: Dialysis
4 Operation and maintenance
4.1 Operation
4.1.1 Optimizing the dialysis
Determining the rinsing time
A rinsing time of two minutes is usually sufficient for completely rinsing
the sample and the acceptor channel. If necessary, this time can be
extended.
Determining the transfer time
The time for the transfer of the preconcentrated acceptor solution into the
sample loop must be chosen in such a way that the part of the acceptor
solution with the highest ion concentration will be transferred into the
sample loop.
The optimum transfer time should be determined for each analysis prob-
lem on the basis of measurements of the individual ion concentrations in
relation to the transfer time and periodically verified.
1 Initial measurement
￭ Set the following values in the software:
– Transfer time: 15 s
– Dialysis time: 10 min
￭ Immerse the sample aspiration capillary in a standard solution
with 10 mg/L of the desired anion or cation.
￭ Start the determination with the appropriate method in the soft-
ware and wait until the chromatogram has been evaluated.
2 Additional measurements
￭ Increase the transfer time in the software by 5 s each time and
start the determination.
￭ Repeat the measurements until the measured area starts to
decrease again.
3 Determining the optimum transfer time
￭ Record the area in relation to the transfer time and determine the
optimum transfer time.
Figure 5 exemplifies this relation.