Use manual loop injections with or without an LC column. You can use this technique in H-ESI or APCI mode.

This technique requires attaching a sample loop, an injection port fitting (also known as a needle port or loop filler), and an LC pump to the divert/inject valve, and then connecting the valve to the API source (or to the API source after passing through an LC column). With the valve in the Load position, you use a syringe to load sample through the injection port fitting into the sample loop, and then switch the position of the inject valve to the Inject position. Switching the valve to the Inject position allows the solvent flow from the LC pump to backflush the sample out of the loop and into the API source.

To set up the system for manual loop injections

Procedure

  1. Connect a sample loop to Ports 1 and 4.
  2. Connect a needle port to Port 2.
  3. Use a Rheodyne fitting to connect one end of Teflon or PEEK tubing to Port 3. Place the other end in a waste container, not shown.
  4. Use red PEEK tubing and a fingertight fitting or an appropriately sized Viper line to connect Port 5 to the outlet of the LC system.
  5. Connect the red PEEK tubing or an appropriately sized Viper line from Port 6 to the API source.
  6. To connect to the H-ESI source, see Connect the sample flow to the H-ESI source.
  7. To connect to the APCI source, see Connect the sample flow to the APCI source.
  8. Injector valve in the Load position for loop injection
    12345
    No.DescriptionNo.Description

    1

    The needle port (also known as a loop filler or an injection port) connects to port 2

    4

    Mobile phase from the LC pump flows into port 5

    2

    The sample loop connects ports 1 and 4

    5

    Excess sample exits to waste through the Teflon or PEEK tubing connected to port 3

    3

    Mobile phase from the LC pump exits from port 6 and flows to the API source

  9. Injector valve in the Inject position for loop injection
    12345
    No.DescriptionNo.Description

    1

    The needle port (also known as a loop filler or an injection port) connects to port 2

    4

    Mobile phase from the LC pump flows into port 5 and enters the sample loop from the back through the connection between ports 5 and 4

    2

    The sample loop connects ports 1 and 4

    5

    Teflon or PEEK tubing connects port 3 to waste

    3

    The mobile phase and sample mixture exits the injection valve through port 6 and flows to the API source