5 Replies Latest reply on Jan 14, 2019 7:49 PM by nkmesong

    A question about component Area in Unknowns Analysis

    nkmesong

      HI everyone´╝îI have a question about component Area within the Unknowns Analysis software, which version is B.09.00, Build 9.0.647.0.

      how to calculate the component Area for a deconvoluted compound in software?

      sum of all the deconvoluted EIC peaks area? like below component area=71+43+57+85+70

      or base peak deconvoluted area times a specified factor?

      or others?

      and when I need to calculate the Estimate conc. I found the formula is Estimate conc.=Base Peak Deconvoluted Area /RF, why do not use the component area here ? could it?

        • Re: A question about component Area in Unknowns Analysis
          ryoboyle

          Hello,

           

          I marked this discussion as a question and added tags to increase visibility.

          • Re: A question about component Area in Unknowns Analysis
            tom_barrett

            Yes, the component is in fact the sum of the ions that deconvolution has grouped into the component.

             

            Why not use it rather than base peak?  It goes back to how Quant works and how that carries over to Unknowns Analysis.  In Quant there is generally a single ion that is selected as the Quantifier.  Frequently this is one of the most intense, if not the most intense (base peak), ions in the spectrum.  So when you import a Quant calibration factor from Quant (ISTD or Target) you are bringing in a "curve" based on a single intense ion.  If you want to approximate (semi-quant) a component in Unknowns Analysis you should ideally use the same ion that Quant uses or it nearest approximation.  The base peak is that.

             

            Now it would be possible to create a interference and background free TIC compound based on the sum of all ions in Quant and transfer that to Unknowns Analysis and then the component would be the logical analogous approximation .  However we currently have no way to switch to component area in Unknowns Analysis.  This request to use Component Area comes up somewhat infrequently and we may address it in the future.

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              • Re: A question about component Area in Unknowns Analysis
                nkmesong

                Hi Tom

                thanks for your answer! there is another question about it.

                "the ions that deconvolution has grouped into the component." Does it mean all the ions showed in the component spectrum as below which extracted by Deconvolution algorithm, including those small peak ions, not only 57+56+41+43+55 ions showed on the left pane?

                 

                My semi-quant rule has something like TIC analysis, so we use the component area rather than base peak area for estimating the concentration of compounds roughly, and I think the Deconvolution area should be more exact area of the compounds. But I need to know how different are they.

                  • Re: A question about component Area in Unknowns Analysis
                    tom_barrett

                    Yes, all ions that you see in the component (even the tiny ones!) are used to create the component.  That list of ions that appear in the Ion Peaks window are just the ones displayed by default (5 most intense).  You can alter the list by clicking on an ion in the Component Spectrum window and you can have up to 10 ions displayed.

                     

                    TIC Analysis will detect peaks via Integration and extract a spectrum by averaging the scans between start and end of peak.  This means it will, unlike Deconvolution, include background signals (examples: air leaks, column bleed) and any compound that coelutes within the peak.  But it still uses the area of the base peak of that spectrum for calculating Estimated Concentration.

                     

                    You may want to consider performing your own calculation of estimated concentration.  There are several ways from exporting to Excel and doing the calculation there to writing a customer script and/or report.

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