How to correctly use NIST search data base

Good morning everyone,

Hope you all had a great new year.

So, the problem that I'm having is that sometimes, when processing a GCMS run through QUALI Masshunter I find some "unknown" compounds. So far so good. 

The problem arise when trying to identify it using NIST. because if i double click the peak to select the mass spectra I get two different spectra for the same peak at the same height, see pictures 1 and 2, the first one is the spectra to the left of center and second the spectra to the right


When using NIST I get two different predictions (as expected) for the two integrations. The question is: which one should I use since both of them are at the highest point?

thank you in advance,

have a great day.

Top Replies

  • Hi ,

    This appears to be scan/SIM GCMS data, where the acquired data alternates between a scan spectrum and a SIM spectrum. You can see what type of spectrum you have extracted by checking the spectrum…

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