Eicom ENO-30, Руководство пользователя

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10. Precolumn
The guard column protects the separation column (P4-NO-PC) from contaminants and prolongs
the life of the column. The precolumn traps substances that will stick to the separation column
material, and not be able to be removed, before they can damage the separation column. The
packing material (NO-PRM) inside the precolumn can easily be replaced. Frequent changes of
the precolumn will increase the useable life of the separation column. As a rough estimation, the
life span of the precolumn column is about 100 injections of denatured protein samples taken
from blood serum plasma or tissue and 200 injections for lower protein samples. These
numbers are strongly influenced by sample preparation methods, precolumn packing and so
forth. Please refer to unit 15-1. (About sample preparation, please refer to Eicom technical
publication entitled “Nitrite and Nitrate Analysis” )
10-1. Determining the Precolumn Condition
If any of the following phenomena occur, it is time to change the precolumn.

As the precolumn is used, the peak shape loses its symmetry. This means that the back
of the peak
returns to baseline very slowing and is said to be “tailing”.

Sometimes if a void develops, or is present after repacking, the peak-tip can be divided.

The pressure of the Carrier pump will rise
as the precolumn’s filter becomes clogged. If
the carrier pumps pressure is 1.5 MPa higher than normal, please repack the precolumn
and change the upstream filter.
To confirm any suspicion that the precolumn is a problem, please replace the precolumn with a
two way joint and inject a standard. If the peak shape improves, the main column is in a good
condition and the pre-column should be replaced.