Decreasing retention times

Possible Cause

Remedial Action

Improper solvent composition

  • Check the premixed solvent for age.

  • Purge the pump.

  • When preparing the system for operation, let it equilibrate for 5-24 hours.

  • Run the script: C01 - Adjust Pump Flow Sensor Offsets.

Increasing retention times

Possible Cause

Remedial Action

Improper solvent composition

  • Check the premixed solvent for age.

  • Purge the pump.

  • When preparing the system for operation, let it equilibrate for 5-24 hours.

  • Run the script: C01 - Adjust Pump Flow Sensor Offsets.

Decreasing flow rate

  1. Run the script: D02 - Test System Tightness (What Should Be Tested = System). Follow the instructions.

  2. Check flow rate settings.

Scattering retention times

Possible Cause

Remedial Action

Pressure fluctuations from pump

Run the script: D02 - Test System Tightness (What Should Be Tested = System).

Air trapped in the autosampler

Run the script: C04 - Purge Sampler with the parameter: Inner Needle Wash Weak Liquid.

Shifts in retention time for a longer period

Possible Cause

Remedial Action

After changing the solvents, the previous solvent has not been removed completely from the pump.

Purge the pump.

Column temperature, sample temperature or solvent temperature is instable

Wait until the column temperature, sample temperature or solvent temperature is fully equilibrated.

Retention time outside the expected range

Possible Cause

Remedial Action

The thermal flow sensors may have a small drift or a shift.

Run the script: C01 - Adjust Pump Flow Sensor Offsets.

Pre-mixed solvents are too old.

  • Use fresh eluent.

  • Use fresh and appropriate solvents (for example, MS-grade).

  • Purge the pump.

Pre-heater used in nano LC applications

Remove the pre-heater (see Replacing the Passive Pre-Heater).

Wrong volume after the column

Check the volume of the capillary connected to the OUT port of the column.

Sample loop variant does not match the set variant

Check whether the setting for the sample loop matches the installed one and correct it if necessary.

Solvent in solvent reservoir does not match the solvent setting

Change the solvent in the solvent reservoir or change the solvent setting.