Troubleshooting 6-3
U n p l u g g i n g t h e C a p i l l a r y
Each capillary is checked before leaving the factory to ensure
proper operation. However, a capillary can become fully or partially
plugged due to several reasons, including those listed in Table 6-2.
As a general rule, if the capillary becomes plugged and the capillary
tip is not broken, first try applying back pressure to the capillary
(see the procedure listed below), then try applying a 5 psi forward
pressure drop across the capillary, and finally try cleaning the
capillary tip or purging the capillary (see
). If the capillary
is still plugged, it should be discarded and replaced (see
).
Table 6-2
Troubleshooting if the Capillary has Become Plugged
Reason
Solution
A contaminant or large
particle in the sample vial
has plugged the capillary
inlet
Back pressure the capillary using the
procedure listed below
Residue has built up on the
inner walls of the capillary
)
Residue has built up on the
capillary tip
The capillary has not been
cleaned properly when
shutting down the
Electrospray
)
The capillary tip has become
broken during maintenance
or handling procedures
Replace the capillary (see Chapter 5,
“
” and
“
Applying Back Pressure to the Capillary
If the capillary becomes plugged, the first attempt to unplug the
capillary should be to apply back pressure to the capillary. The
following procedure should unplug the capillary if a contaminant or
large particle in the sample vial has plugged the capillary inlet:
1.
Remove power from the instrument and turn off all flows.
2.
Connect a compressed air source capable of generating 5 psi
pressure or a large syringe (>50 cc) to the aerosol exit. Do
not
exceed 5 psi since a relief valve is attached to the Electrospray
chamber. If the relief valve opens, remove all pressure from the
Electrospray chamber and the relief valve will reset
automatically.
