Peak tailing

Possible Cause

Remedial Action

Extra column volume too large

  • Use short capillary connections with a suitable inner diameter.

  • Use the Viper capillaries appropriate for your application (refer to the script: A06 - Change Fluidics / Workflow).

Improper capillary connections

  1. Check fittings for correct placement.

  2. Loosen and retighten Viper fittings (see Connecting NanoViper Capillaries).

  3. Use the Viper capillaries appropriate for your application (refer to the script: A06 - Change Fluidics / Workflow).

  4. Replace the capillary.

Dead volumes in capillary connections

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

  2. Inspect the capillary and replace the capillary, if necessary.

Peak broadening

Possible Cause

Remedial Action

Extra-column volume too large

  • If early peaks are broader than later eluting ones, check the capillary I.D. and the capillary length, for example.

  • Use a capillary with a smaller volume for the connection between column compartment and downstream detecting device.

Temperature gradient in column

  • If using flow rates > 50 µL/min, in particular with 1-mm ID columns in the flow range of 50-100 µL/min, use a pre-heater.

  • If a pre-heater is already installed, check the pre-heater for correct installation. If necessary, reinstall the pre-heater (see Replacing the Passive Pre-Heater).

Capillaries partly clogged

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

  2. Replace the capillaries.

Sample loop partly clogged

Run the script: D01 - Test System Back Pressure.

Dead volumes in capillary connections

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

  2. Properly install the capillary connections.

  3. Tighten the capillary connections.

  4. Replace the capillary.

Peak broadening, increased dead time

Possible Cause

Remedial Action

After-column volume high

  • Use a capillary with an appropriate:

    • Inner diameter

    • Length

  • Inspect the capillary. If it is defective, replace the capillary.

Needle seat filter clogged

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

  2. Replace the needle seat, if necessary.

Triangular peaks

Possible Cause

Remedial Action

Column overloaded (sample concentration too high)

Dilute the sample.