W2690 HPLC do you need to prime all the lines before running samples?


I run a method on HPLC Waters 2690 and its a gradient that used lines A and B and then D for washdown. I have heard people saying you don't need to wet prime the lines you aren't using so in this case C, but I read another article saying its best practice to prime out ALL the lines as its good for the mixing chamber and mechanism of the instrument. What's best for priming the lines in this case? I normally start by priming the seal wash for about 20 mins, followed by priming the needle wash a few times, doing 40 cycles for Purge Injector, followed by 10 mins each wet prime of A B C and D, then slowly ramp up flow rate to initial conditions and equilibrate for an hour before starting a run.

Any thoughts on this procedure?

Best Answer

  • MarcNoble
    Answer ✓
    Hi Empower2019

    It is recommended to prime all of your solvent lines on an Alliance system before running - even the lines you are not using.  The reason being that all of the degasser solvent chambers are connected to a single vacuum engine and it can only efficiently degas solvent in the lines you are using if all of the chambers are full of solvent.

    That said, on the lines you are not using for analysis 2 minutes of wet prime every other day should be sufficient.

    Hope that helps,



  • Thanks Marc, i work on worst case scenario where i wet prime all the lines for 10 mins each. I knew there was a reason, i didnt know its down to the degasser on the solvent chambers. Thats good to know.
  • 10 Minutes each is probably a bit excessive.  You can probably get away with 4 minutes each if you have Performance Plus Degasser chambers (those are brown, the traditional ones are white and would require an extra minute or two.)
  • Always prime ALL of the lines (100% each, not 25%) with fresh mobile phase before you use the system. This is critical to proper operation of the system and helps maintain the seals over time (esp in the GPV, which will dry out, then leak or get stuck if not used on a regular basis). Flushing fluid through ALL channels insures that ALL channels of the degasser are primed with fresh fluid. The degasser requires that ALL channels be filled with liquid at all time for proper function. If air is left in any chamber it increases the wear-tear on the vacuum pump reducing the lifetime of the parts (and air can end up in a chamber that is not used because the solvent inside is evaporated over time from normal use). Never plug chambers. Use them all, and yes, if you have one channel you rarely use then fill that line with a suitable liquid that is compatible with your applications and manually flush it out every few days to keep it primed.