When

TIP

With conventional use of the Vanquish Neo system as recommended in this manual, regularly flushing the pump is usually sufficient. See Flushing the Pump to Avoid Contamination.

For example, if ghost peaks appear reproducibly in your blank chromatogram without injecting a sample, consider a harsher cleaning procedure. Follow the instructions below.

Parts and additional items required

  • Appropriate backpressure capillary, generating about 20 – 90 MPa at a flow rate of 50 µL/min in water (for example, nanoViper capillary, fused silica, inner diameter: 20 µm, length: 350 mm)

  • 6 molar (6 M) nitric acid (HPLC-grade)

  • Waste container (for collecting the nitric acid)

  • Fresh water (HPLC-grade)

  • Fresh acetonitrile (HPLC-grade)

  • New solvent reservoirs with fresh solvent

  • New frits for solvent line filters

Follow these steps

  1. Install the backpressure capillary on the pump outlet. Guide the free end of the capillary to the waste container.

  2. Replace the frits in the solvent line filters with new frits.

  3. Replace the installed waste container with the new waste container to prevent any chemical reaction between the nitric acid and the solvent in the waste container.

  4. Flush the pump with 6 M nitric acid for 2 hours, applying 50% B at a flow rate of 50 µL/min.

  5. Flush the pump with fresh HPLC-grade water until the pH value is neutral.

  6. Remove the waste container with the nitric acid and re-install the waste container that was installed previously.

  7. Flush the pump with fresh acetonitrile for 2 hours, applying 50% B at a flow rate of 50 µL/min.

  8. Connect the new solvent reservoirs, which contain fresh solvent.

  9. Uninstall the backpressure capillary and reconnect the system as required by your application.

  10. Purge the pump.

  11. Equilibrate the system.