Spiky Peak Tops But Flat Baseline; Large Baseline Offset - Agilent Technologies InfinityLab 1290 Infinity II User Manual

6 Troubleshooting and Diagnostics
General Problems

Spiky peak tops but flat baseline

Probable cause
1
2
3
4
5
6

Large Baseline offset

Probable cause
1
2
3
4
Agilent InfinityLab ELSD User Manual
Inconsistent nebulization
Incorrect gas being used
Poor regulation of inlet gases
Insufficient smoothing
Sample precipitation during nebulization
Inconsistent pump flow rates
Inefficient evaporation
High concentration of nonvolatile buffer or
stabilizer
Contaminated diffuser
Optics Heater failed
Suggested actions
Nitrogen is the recommended gas - others can
be used but may not nebulize as efficiently.
Change gas to nitrogen or evaluate different
nitrogen sources.
• If using bottled gas, check that gas regulator
is functioning correctly and giving consistent
flow.
• Alternatively, use a pulse dampener.
The broader the peaks, the higher the smoothing
value is required. Increase smoothing to 50 for
Flash separations.
• Reduce sample concentration or inject same
loading in larger volume.
• Check sample solubility in mobile phase
eluents.
See remedy for pump pulsation in the baseline
noise section.
Suggested actions
Increase the evaporator temperature and/or gas
flow.
Use a lower concentration of stabilizer,
unstabilized solvent or, a more volatile buffer
(ammonium acetate or ammonium formate).
Perform cleaning procedure.
Refer to local distributor or Agilent Technologies.
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