Ion 44 baseline

Hi! We are actually having some issues with my GC-MS. Some months ago started appearing an annoying ion during all the TIC, the m/z = 44. Some threads comment that could be some air leak. we have checked all the possible parts of the chromatograph and seems not to be that. Also, the autotunes are apparently correct and they do not show me any leak. 

On the other hand, ions 18 (water), 28 (nitrogen) and 32 (oxigen) are very high. I'll attach to this post some screenshots with a blank TIC. The peaks of the blank TIC are due to the m/z = 28 (nitrogen). We want to solve this problem because some peaks appear under the baseline and it is quite annoying.

 

Thank you for your attention!

attachments.zip

Top Replies

  • hello ,

     

    1) to see when/how the unwanted peaks come:

                   please create an extracted TIC once: Chromatogram > Extract ion chromatogram > type in all masses (18, 28...)

    EXAMPLE:

      

    now we can see if…

Parents
  • Before you isolate the MSD from the GC, try changing you helium cylinder.  The 44 may be coming from you carrier gas. You can also pull your column from your inlet and plug it with a septum.  The residual gas in the column will be suck out in about 5 minutes.

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  • Before you isolate the MSD from the GC, try changing you helium cylinder.  The 44 may be coming from you carrier gas. You can also pull your column from your inlet and plug it with a septum.  The residual gas in the column will be suck out in about 5 minutes.

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