8 | Help with faults
Büchi Labortechnik AG
82/102
Operation Manual Pure Chromatography Instruments
8.6 Faults, possible causes and solutions (detection)
Malfunction Possible cause Solution
ELSD signal is low or
disappears
Sample is too volatile u Sample cannot be detected
by ELSD due to its volatility.
No or low ELSD carrier gas flow u Verify there is gas supplied
to the instrument.
u Check for leak in the gas
lines.
u Verify that there is gas flow
to the nebulizer from the
ELSD sampling valve.
u Verify that there is gas flow
to the ELSD sampling valve.
Sample stuck on column u Use stronger solvent or
change column chemistry.
ELSD not equilibrated long
enough
u Restart run to re-stabilize
and rezero ELSD baseline.
Blocked nebulizer u Sonicate nebulizer to clean
or replace the nebulizer.
Blocked ELSD line u Trace the blockage and
replace the blocked line.
Rotor and/or stator in ELSD
Sampling valve is worn, dirty,
or clogged
u Replace the rotor and/or
stator.
Poor ELSD Peak
shape
Blocked nebulizer or nebulizer
tubing
u Clean the nebulizer or
replace the nebulizer tubing.
Nebulizer tubing is not prop-
erly connected
u Reinstall the nebulizer
tubing properly.
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