High baseline drift

Possible Cause

Remedial Action

System not sufficiently equilibrated

  1. Flush the system until equilibration. Usually, a volume of 5–10 times the column volume will be sufficient.

  2. If flushing the system does not solve the problem, purge the pump and let the system equilibrate for at least 5 hours.

Unstable environmental conditions

Make sure that the temperature and the humidity are constant.

Absorption of eluent changes when gradient is run

Absorbing additives may change the absorption spectrum, depending on the solvent. Consider varying additive concentrations to level the drift.

Autosampler contaminated

Run the script: B03 - Clean Up System.

Column contaminated

Clean or replace the column.

Old solvent present in metering device head or sample loop

To purge the metering device or sample loop, run the script: C04 - Purge Sampler with the parameter Inner Needle Wash Strong Liquid.

In general, when replacing the solvent reservoirs, run the script: B01 - Change Liquids / Solvents.

Solvents degraded or inhomogeneous

  • Before starting an analysis, make sure that the solvents are already homogenized in the reservoirs.

  • In aqueous solvents, microorganisms can grow and degrade the solvent. To replace the solvent with a new solvent reservoir containing fresh solvent, run the script: B01 - Change Liquids / Solvents. Follow the instructions.

Non-periodic baseline fluctuation, high noise

Possible Cause

Remedial Action

Air trapped in the system

Purge the pump and the autosampler.

Solvent is degraded or of poor quality

  • Use fresh eluent.

  • Use appropriate solvents (MS-grade).

  • To change the solvent, run the scripts: A01 - Set Pump Solvent Types and then B01 - Change Liquids / Solvents.

Periodic baseline fluctuation, pulsation

Possible Cause

Remedial Action

Pressure fluctuations from pump

  • Purge the pump.

  • Run the script: D01 - Test System Back Pressure.

Air trapped in the system

Purge the pump.