Eicom ENO-30, Руководство пользователя

Страница: 43 / 57

38 | P a g e
11. Separation Column (NO-PAK)
11-1. NO-PAK

The size of the separation column (NO-PAK) is ø4.6 mm and 50 mm in length, and it is
packed with a styrene polymer gel. The separation quality of column is verified before
shipping.

If methanol should enter into the separation column, the equilibrium with the Carrier will be
upset and no peaks will appear. You may have to deliver Carrier to the column for up to 8
hours until retention times are stable. This is sometimes the case with new columns.

The inside of separation column should not be allowed to dry out. So when storing, the
column ends should always be stoppered with stop fit connectors and left at room
temperature.

Generally, the columns pressure against the flow is about 1.0 to 2.0 MPa. Do not expose the
column to excessively higher pressures.
11-2. Identification of Separation Quality
As the column is used, the retention time of the peaks will typically decrease and the Nitrite and
Nitrate peaks may begin to broaden and overlap. To confirm that the problem is the separation
column, remove the precolumn and replace with a two way joint instead of the precolumn. Make
a standard injection. If there is no change, then it’s probably the separation column that needs to
be replaced. In addition, the Nitrite peak, and the negative dip just before it, will not separate
well. To check the quality in this case, please use water-diluted standard solution. This makes
the negative dip more apparent.
11-3. Washing the Separation Column
If the quality of the precolumn is maintained as described above, the separation column will not
need to be washed. However if the separation begins to show broad peaks because of the
separation column, you may want to wash the column to try to improve the separation.
1. To wash, reverse the column direction and do not connect the outlet.
2. Place directly in waste vessel.
3. Now run water at 0.5 mL/min for 1 hour, and then switch to 100% methanol for at least
one hour, but you may let it run over night.
4. Then switch back to water for an hour.
5. Now you can put the column back to the forward direction and deliver Carrier for up to 8
hours to re-establish the equilibrium.