Baseline Spikes; Low Sensitivity - Agilent Technologies InfinityLab 1290 Infinity II User Manual

6 Troubleshooting and Diagnostics
General Problems

Baseline spikes

Probable cause
1
2
3
4
5

Low sensitivity

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