Waters 2690

Hello all

Can you use the waters 2690 without the Needle wash frit?

I got a molecule that retain in the frit a lot. once i remove it for a new frit the next black is clean but after the first injection of my sample stay there forever.


  • I doubt this "sample loss" is related to the frit.  The needle wash frit is meant to have semi-intimate contact with the outside surface of the needle. Typically, only a few nanoliters has been calculated to be on the outside of the needle. The sample is on the inside of the needle and can't be "lost" to the frit.  All this being said, I would advise against not using the frit as it "controls" the NW solvent/air mixture that "scrubs" the needle. Without the frit I envision 2 negative consequences. One is the use of less NW solvent as the NW pump will preferentially pull air rather than (more viscous) NW solvent. Second is, most likely, increased carryover due to inadequate washing of the needle. 
  • Josee
    You may also want to try the new Performance Plus Seal Pack that no longer has a lower needle wash frit.  You could use the Performance Plus Seal Pack Replacement kit 700011784 or the Enhancement kit 700011805 which includes the kit mentioned above and a new needle wash line and valve and load firmware 3.04 from the Waters.com website.