Introduction to the Agilent 7100 Capillary Electrophoresis System

6 Troubleshooting and Diagnostics
CE Problem Solving
Problems with the Replenishment System and Buffers
Containing SDS
When a vial is replenished the SDS foam may stick to the side of the vial. The
empty function draws air around the foam into the replenishment needle.
When filling this vial, a set of new foam bubbles is introduced into the vial
before the fresh buffer. The surface sensing system recognizes the first foam
bubble as liquid. So the final liquid level is not at the height it should be. It may
also happen that the vial contains no buffer liquid but only foam. The result
could be seen as low current or even no current supplied.
As a workaround we recommend programming a replenishment program in
two steps.
1 Replenish to a level about 0.2 cm higher than required.
2 Fill to the desired level.
If the fill results a level higher than the desired one, the vial is emptied to the
level without using the sensing function and the foam has no influence.
As an example: the desired height is 1.4 cm
1 Replenish vial XX to 1.6 cm (0.2 cm more)
2 Fill vial XX to 1.4 cm
Alternative: No Replenishment Necessary.
1 Fill several vials with buffer.
2 Program methods which use these vials as the inhome and outhome vials
(for example vials 4, 5, 6, 7).
Method 1:
inhome = 4, outhome = 5
Method 2:
inhome = 6, outhome = 7
168 Agilent 7100 Capillary Electrophoresis System User Manual