4 Replies Latest reply on Feb 9, 2018 4:52 AM by james_jenkins

    mass 32 is not detected

    bperezf

      I am working with a GC/MS 6890 5973.

      And in the last tune there is not response for the mass 32. Could you imagine any reason?

       

      Thanks

        • Re: mass 32 is not detected
          james_jenkins

          I have updated the tags for better visibility. Mass 32 is oxygen  which is one of the things we work to minimize in a GCMSD. The less air in a system, the better the mean free path. Sounds like a tight system, but I would need more information on why you are concerned about this.  Usually lack of 32, 28 and 18 is a good thing.

          James

          • Re: mass 32 is not detected
            cmorrow

            Bperez, note that with EPA Method 8260 we start scanning with m/z = 35, specifically we go m/z = 35-270.  Also as James said, 32, 28, and 18 are O2, N2, and H2O respectively---all analytes you do not want in GC/MS as they would impair the vacuum and diminish the mfp.

            • Re: mass 32 is not detected
              james_jenkins

              Hi bperezf,

              I went ahead and flagged this post as “Assumed Answered”.  If you still need help though, please let us know and we would be happy to continue working with you. If the issue is resolved please feel free to update us or mark correct answer.

              Regards

              James