￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭
5 Operation and maintenance
850 Professional IC–Anion – MSM-HC – MCS – LP Gradient
￭￭￭￭￭￭￭￭
93
5.7
Inline sample preparation
To protect the separation column
against for-
eign particles which can affect the separating efficiency, we recommend
that all samples undergo a microfiltration (filter 0.45 µm). The ultrafiltra-
tion cell can be used for
filtration
(see documentation on the
IC Equip-
ment for Ultrafiltration
).
Samples containing significant amounts of
gas
should be degassed. The
sample degasser
(if available) is used for
degassing.
Matrix-loaded
samples (e.g. blood, oil) should be prepared for the mea-
surement by means of dialysis (see documentation on the
IC Equipment
for Dialysis
).
If the concentration of the sample is too high, it should be
diluted
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.
5.8
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 sample vessel to the end of the sample loop.
Ascertaining the transfer time
The transfer time depends on the pump capacity of the peristaltic pump,
the total capillary volume and the volume of the gas removed by the sam-
ple degasser (if used) - in other words the amount of gas in the sample.
1 Emptying the sample path
Pump air through the sample path (pump tubing, tubing connec-
tions, capillary in the degasser, sample loop) for several minutes until
all liquid is displaced by the air.