6
Troubleshooting and Diagnostics
General Problems
Agilent InfinityLab ELSD User Manual
68
Baseline spikes
Low sensitivity
Probable cause
Suggested actions
1
Particulate matter in the gas supply
Filter the incoming gas, or change the supply.
2
Column shedding
Replace column or fit an inline filter with a 0.2 µm
membrane filter directly after the column.
3
Poor nebulization
•
Check solvent flow rate into ELSD is
constant.
•
Check inlet gas flow is >60 psi and stable.
4
Insufficient evaporation
Increase the temperature of the evaporator by
10 °C until the baseline noise decreases.
5
Nonvolatile additive in mobile phase
Use a volatile mobile phase.
Probable cause
Suggested actions
1
Partial blockage in nebulizer or nebulizer inlet
tube
Pump a 50/50 water/acetone mixture into ELSD
at highest flow rate possible (do not exceed
5 mL/min) for 16 h.
2
Internal solvent trap is empty
Fill the front solvent trap with liquid until any
excess flows out through front drain tube.
3
Gas pressure too low
Ensure inlet gas pressure
>
60 psi.
4
Laser power
Verify by switching the unit from
STANDBY
to
RUN
and check offset.
5
Optical chamber is contaminated
Clean contamination from widows in optical
chamber.
6
Diffuser saturated with solvent
Stop the eluent flow and increase the evaporator
temperature to maximum. Increase the flow rate
to 2.8 SLM and wait 1 h.
