15
Intended use
Accumulation of a sample
Basics
The accumulation of a sample is employed in chromatography,
for example in the following case:
Samples that are very diluted by solvents
Note:
The solvent is fed through a detector
A
into the waste
container. As soon as sufficient sample has been accu-
mulated on the precolumn, the valve is switched over
and the thus accumulated sample is flushed with a dif-
ferent solvent to the analytical column.
Fig. 12
Sample accumulation on precolumn – injection from the
6P/3C valve
From the injection valve, the precolumn is filled with solvent A
through the channel
2->1
. From channel
4->3
, the eluent is fed
through the detector
A
into the waste container.
Note:
Make sure there is no pressure when switching
between the columns so that the columns are not
damaged.
After switching over the valve to the channel
5->4
, a solvent B
are flushed back in opposite direction through the precolumn.
The accumulated sample is flushed through channel
1->6
onto
the analytic column and measured with detector
B
.
Fig. 13
Sample accumulation – analysis of the accumulated sample
Injection
on precolumn
1
2
3
4
5
6
Precolumn
Injection
Pump A
Eluent A
Pump B
Eluent B
Detector B
Column
Detector A
Waste
Switchover
of the direction
of flow
Precolumn
Column
Injection
Pump A
Pump B
Eluent B
Detector B
Eluent A
1
2
3
4
5
6
Detector A
Waste
