How to Change Mobile Phase Bottles on an HPLC

How to Change Mobile Phase Bottles on an HPLC

Changing Mobile Phase Bottles 


The purpose of this procedure is to correctly change mobile phase bottles on an HPLC.


This procedure applies to HPLC instruments used by Ionization Labs and its clients.


It is the responsibility of the user to confirm that both bottles of mobile phase are the same type (A vs B) and that the new bottle being attached is not expired. It is also the responsibility of the user to update the new volumes in Cann-ID and/or Chemstation.

Materials and Equipment


  1. Mobile Phase A and/or Mobile Phase B


  1. HPLC system (Autosampler or Manual Injector)

Safety Issues

  1. Appropriate PPE must be worn when handling chemicals. This includes safety gloves and eyewear.

Important: Users should familiarize themselves with the SDS for each Mobile Phase and their hazards.


  1. Ensure that the HPLC is either not running a test or In the ‘Sleep’ status.

  2. Open the top faceplate of the machine.

  3. Release the black pressure valve by turning it counterclockwise 2 rotations.

  1. Check Chemstation to ensure the pressure has decreased to below 3 bar.

  1. Place a new mobile phase bottle near the machine, shake thoroughly for 5 seconds to homogenize the mobile phase, and remove the cap.
  1. Verify that the bottles being changed are the same type by matching the labels on the mobile phase lines – Mobile Phase A to the "MPA" line and Mobile Phase B to the "MPB" line

  1. Remove the cap apparatus from the old mobile phase bottle and place the end quickly but gently into the new bottle.

  2. Tighten the cap apparatus on the new bottle and place the regular cap onto the old bottle.

  3. Tilt the bottle so that any air bubbles, underneath the glass filter, get drawn up by the filtering lines or are released to the top.

    IMPORTANT: To adjust the Mobile Phase volumes in Cann-ID, enter the new volumes in the control panel, from the right side of the screen, and then click the button Change A or Change B.

  1. Close the pressure knob by turning it clockwise 2 rotations.

  2. Let the machine sit for 5 minutes.

  3. Check Chemstation to ensure that the pressure increases.

  4. Put the top faceplate back onto the machine.

Video SOP Available Here

Your mobile phase bottle(s) are now replaced and you are ready to continue analysis with HPLC and Cann-ID.

IMPORTANT: After replacing the bottle during the day, a 5-minute equilibration period (wait time) is REQUIRED. After this period, you can begin running samples again.

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