6 inline sample preparation, 7 rinsing the sample path, Inline sample preparation – Metrohm 872 Extension Module User Manual
Page 63: Rinsing the sample path
￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭
6 Operation and maintenance
872 Extension Module IC Module
￭￭￭￭￭￭￭￭
55
6.6
Inline sample preparation
To protect the separation column against foreign particles which can
affect the separating efficiency, we recommend that all samples undergo
a microfiltration (filter 0.45 µm). The ultrafiltration cell can be used for fil-
tration (see manual of the IC Equipment for Ultrafiltration).
Matrix-loaded samples (e.g. blood, oil) should be prepared for the meas-
urement by means of dialysis (see manual on the IC Equipment for Dialy-
sis).
If the concentration of the sample is too high, the sample should be dilu-
ted before feeding (see documentation on the IC Equipment for Sample
Dilution).
For the sample preparation methods Neutralization (replacement of e.g.
Na
+
with H
+
) and cation exchange (replacement of e.g. heavy metals
with H
+
), a sample preparation module (SPM) is used.
For an overview of all Metrohm inline sample preparation methods go to
6.7
Rinsing the sample path
Before a new sample can be measured, the sample path must be rinsed
with it so that the measuring result is not falsified by the previous sample
(Sample carry-over).
In the case of automated sample feeding, the rinsing time should be at
least 3 times the transfer time.
The transfer time is the time required by the sample to flow from the sam-
ple vessel to the end of the sample loop. ##NO_MATCH##.
Ascertaining the transfer time
To ascertain the transfer time, proceed as follows:
1 Emptying the sample path
Pump air through the sample path (pump tubing, tubing connec-
tions, sample loop) for several minutes until all liquid is displaced by
the air.