Mass Hunter Qualitative analysis by custom Library issue

Hello all,

I am new to the mass hunter qualitative analysis software. I am trying to identify some compounds by creating my own custom library. I have created the library in PDCL by giving the mass of compound, formula of compound and compound name. But when I tried to do the analysis with it, the software is not showing any matched compound names. It does processing for some time but then in the compounds window, nothing is showing. It is not saying that nothing is matched. Even I am sure that the compounds which are in the library should match the samples but still its not showing anything. What could be the possible errors?

  • Hi, I am stuck having this same issue trying to build a custom library to identify compounds from GC/MS RT and spectra. Since (I think) the only option for identification that works for GC/MS in the version of qual I have is to match by "Mass and retention time" rather than by retention time alone, I suspect the problem might be that there is not a way for the program to identify mass when I am only using single-quad MS data as input. I will be interested to see whether someone offers a solution to your problem.

  • Hello  ,

    To troubleshoot the issue you will need to first verify you are able to find the compound and then troubleshoot the identification. Find by Formula requires a peak be integrated for the expected accurate mass EIC. Find by Molecular Feature requires that the 3D signal match your method criteria. I would start by manually making certain there is signal for your expected molecular ion and going from there.

    The Qual Familiarization Guide has some good general usage instructions and also some examples of using Find by Formula and Find by Molecular Feature. It should be available on your MassHunter PC as part of the LCMS Data Analysis Resources.

  • So I should start doing it "Find my formula" or "find by molecular feature"??

  • Hello  ,

    I apologize for the delayed response.

    You can use either find by method to attempt to find your targets, but to troubleshoot the issue you need to find your target manually by extracting the EIC for the expected molecular ion. Once you find your target and manually extract the spectrum you can examine the data to determine what criteria are not being met in your method settings. Then you can decide if you need to adjust your acquisition parameters to improve the data or adjust your method so that the targets can be found. 

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