Fixing:
head space or void
If your column
has developed a head space or void at the column inlet:
1. Consider
simply replacing the column. Void spaces can often be repacked, but
the procedure is time consuming, far from foolproof, and often only
temporary. Unless the column is extremely expensive or you have no
replacement column available, replacing the column can be the most
cost-effective solution.
2. Get
replacement packing material from the outlet end of an old column,
or purchase inert, impermeable glass beads. Make a thick paste of the
filling with an appropriate solvent (usually the organic solvent from
the mobile phase); the paste should have about the same consistence as
spackling compound.
3. Use a small
spatula to dig out any obviously contaminated or discolored packing
from the inlet end of teh column and then use the same spatula to force
the filling paste into the void. Press the paste in as tightly as
possible, then scrape off the exess exactly level with the end of the
column tube.
4. Carefully
rinse the end of the column tube, including the ferrule and or
threads, with organic solvent (be careful not to disturb your newly
packed bed, then replace the inlet frit and end fitting and tighten per
the manufacturers' recommended torque setting.
5. Connect the
column to the system and pump mobile phase through until the
baseline stabilizes (this may take quite some time as trapped dissolved
air forms bubbles, then test the column.
The re-packing may
have to be done several times in succession as the newly packed bed
will compress slightly under pressure.
© 2006
LC Resources, Inc. all rights reserved