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

Baseline spikes

Probable cause
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Low sensitivity

Probable cause
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Agilent 1290 Infinity II ELSD User Manual
Particulate matter in the gas supply
Column shedding
Poor nebulisation
Insufficient evaporation
Non-volatile additive in mobile phase
Partial blockage in Nebuliser or nebuliser
inlet tube
Internal solvent trap is empty
Gas pressure too low
Laser power
Optical chamber is contaminated
Diffuser saturated with solvent
Troubleshooting and Diagnostics
General Problems
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
Usa 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 S/By 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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