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Agilent Unknowns Analysis - Search Algorithm

Adrsto

Hi Everyone

I started using Unknowns Analysis a while ago. I understand most of the functions and parameters in the program, but there is something that has been on my mind recently. I have noticed that when I compare the results of my standards in the Unknowns Analysis to the NIST I can see that the NIST is far better at predictions, having the top hit listed as the correct compound. Meanwhile the Agilent software is not so accurate. For the record, I am familiar with the forward and reverse search functions and it does not really matter how well I optimize it for the batch, the NIST still predicts the component far more accurately.  

Is there any way I can implement the search algorithm of the NIST to the Unknowns Analysis software. I am aware of the GotoNISTMSProgram.Unknowns script, but that just exports the spectrum of the single component to NIST. I am looking for something automatic. 

Thanks. 

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    Hello  ,

    I apologize for the delayed repsonse.

    It is not possible to use the NIST algorithm itself within Unknowns Analysis. As you mentioned, you can adjust the forward and reverse settings and enable the Adjust Score option, which from the dataset manual does the following -


    NISTCompatibility determines whether to adjust the score by weighting like the NIST algorithm. If checked, the algorithm uses the maximally NIST-compatible dot product calculation (“An Integrated Method for Spectrum Extraction and Compound Identification from GC/MS Data”, Stein, S.E. J. Am. Soc. Mass Spectrom. 1999 770-781) which gives the results that are as close to NIST as possible (within the constraints of the MH search algorithm); otherwise uses an alternative dot product for score calculation which might give better results. Default is false.

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  • 0

    Hello  ,

    I apologize for the delayed repsonse.

    It is not possible to use the NIST algorithm itself within Unknowns Analysis. As you mentioned, you can adjust the forward and reverse settings and enable the Adjust Score option, which from the dataset manual does the following -


    NISTCompatibility determines whether to adjust the score by weighting like the NIST algorithm. If checked, the algorithm uses the maximally NIST-compatible dot product calculation (“An Integrated Method for Spectrum Extraction and Compound Identification from GC/MS Data”, Stein, S.E. J. Am. Soc. Mass Spectrom. 1999 770-781) which gives the results that are as close to NIST as possible (within the constraints of the MH search algorithm); otherwise uses an alternative dot product for score calculation which might give better results. Default is false.

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