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MartMM
Portugal
1 Posts |
 Posted - 12/10/2018 : 05:04:16 AM
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Hey guys!
I have a file coming from HPLC.
If I only select the zone of the chromatogram that interests me, and truncate it, I get a graph similar to this one (https://www.originlab.com/doc/Tutorials/PeakFitting-Baseline) but without the negative peak, only with positive peaks.
What is the most correct baseline to use in this case? Is it even necessary that the Fit Peaks converge to get the real area of the peaks?
If I adjust the cumulative curve to my peaks in Fit control -> Peak Fit Parameters, will the areas that I have fixed be valid?Even if Fit Peaks does not converge?
Is this sequence correct?
In the original file, I define a baseline as a straight line and subtract baseline -> Finish.
Then I select the zone with the peaks that interest me and I make another graph.
So I apply the baseline as constant with y = 0 for the truncated chart.
Than I go all the way (Fit peaks Pro) and I manually adjust the cumulative curve for my peaks in Fit Control Parameters, but it does not converge.
Are the peaks areas that I define valid?
I'm sorry, I know there are many questions but they all have the same purpose.
I will be very grateful if you can help me 
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YimingChen
1684 Posts |
Posted - 12/10/2018 : 2:06:02 PM
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Hi,
The baseline in the example you attached is using an exponential decay curve. If your data is similar, you can try that. The real area of the peaks is obtained by integrating the peak curve, so doesn't need peak fit to be converged.
On the other hand, the area you fixed in Fit Control dialog is a fitting parameter.(You can check the formula in Formula tab), this is not valid if fitting is not converged.
If you follow the tutorial in your attached webpage, you just need to select Fit Peaks(Pro) as the purpose, then define baseline, subtract baseline, do peak fitting, fix the parameters in Fit Control, then check if it is converged.
Please send your file to <tech@originlab.com> if you have further questions. Thank you.
James |
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Correct baseline and convergence HPLC chromatogram