9 Replies Latest reply on Jan 9, 2019 2:46 PM by ryoboyle

    Integrating peaks with Chemstation

    emartinez

      I would like to be able to set a threshold for peak integration for peaks outside my established calibration that doesn't affect the peaks in the calibration.  Is this possible in Chemstation? 

      For example, if I have three peaks I am calibrated for at a peak height of 100 and I want to integrate all unknown peaks present at peak height of 150, is there a way to set the integration to grab only those unknown peaks at 150, but still integrate all three compounds observed in my calibration table regardless of their peak height? 

      Thanks

        • Re: Integrating peaks with Chemstation
          ryoboyle

          Hello,

           

          Would you mind providing us with the revision of ChemStation software that you are using?

          • Re: Integrating peaks with Chemstation
            mr.white

            Hello,

             

            You can use the integration events.

             

            For example " Height Reject" 90. So it doesn't integrate every Peak below 90, but above 90.

             

            Regards

            White

              • Re: Integrating peaks with Chemstation
                abdur

                Yes, that might work.  You can also set timed integration events, so that for certain known time segments where your unknowns would fall , you can set the height reject to one value.  Then you can create a time segment for your calibrated peaks and make the height reject an alternate value.  These settings can be found in data analysis, under integration, integration events...

                 

                I think a more important question would be, why would you want to do this?

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                  • Re: Integrating peaks with Chemstation
                    ryoboyle

                    abdur is right. Assuming this is Multi-Technique GC/LC ChemStation or OpenLab CDS ChemStation, integration events are all time based. There is no way to apply integration events only to calibrated compounds, but if you know when your peaks or interest are eluting then you can apply integration in those time periods and turn integration off for all other time periods.

                     

                    If this is OpenLab CDS ChemStation, you also can use intelligent reporting to filter your results so that only the results of calibrated compounds are displayed on your report. While other peaks might be getting integrated, they would not show up on your report.

                     

                    • Re: Integrating peaks with Chemstation
                      emartinez

                      We want to flag large unknown peaks in an automated way that are outside our typical calibration without having to capture every extra little peak that shows up on the spectrum. 

                        • Re: Integrating peaks with Chemstation
                          ryoboyle

                          As far as integration goes, the best solution would be to try to find values for the initial integration events (slope sensitivity, peak width, area reject, and height reject) which limits the amount of background noise that is integrated while still allowing all of your peaks of interest to be integrated. You can also play around with some of the timed integration events, though you may need to update these on a regular basis depending on retention time shifts.

                           

                          From a reporting standpoint, you could set up an intelligent report with two result tables. One would be filtered to report results only for calibrated/identified peaks while the other would be filtered to only report results for unknown peaks. You could then add another filter to your unknown peaks table so that only unknown peaks with a height greater than 150 will be reported:

                           

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