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 Peak Fitting Difficulty: Chromatography		  New Topic  Reply to Topic
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CBroomell

USA
2 Posts
Posted - 05/10/2023 :  10:42:06 AM  Show Profile  Edit Topic  Reply with Quote  View user's IP address  Delete Topic
2023b Pro running on Windows 11

I'm looking for tips/suggestions for multi-peak fitting of an HPLC chromatogram. I'm getting reliable peak identification (using either 2nd deriv or residuals after 1st deriv)...I say "reliable" based on the peak IDs relative to "visual squintometry" of the chromatograms. However, I'm not getting the fits to converge at all.

There is a reasonable amount of tailing of the main peak (with a few noticeable inflects...see above). It is possible that there may still be some small hidden peaks in the declining slope but I suspect that the analyte is actually tailing. If so...I don't think Gaussian peaks will be appropriate.


Has anyone experienced similar situations (i.e., fitting systems where there are column interactions)? I'm happy to share XY data if anyone wants to take a crack at it.

Thanks in advance,
Chris

aplotnikov

Germany
169 Posts
Posted - 05/10/2023 :  2:07:19 PM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
You may read the book "Data Analysis and Signal Processing in Chromatography" https://www.elsevier.com/books/data-analysis-and-signal-processing-in-chromatography/felinger/978-0-444-82066-2 - just to take an impression on the complexity of your question.
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CBroomell

USA
2 Posts
Posted - 05/10/2023 :  4:01:59 PM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
quote:
Originally posted by aplotnikov

You may read the book "Data Analysis and Signal Processing in Chromatography" https://www.elsevier.com/books/data-analysis-and-signal-processing-in-chromatography/felinger/978-0-444-82066-2 - just to take an impression on the complexity of your question.



Thanks for the recommendation. I am pretty familiar with the complexity of the situation and I've been using Origin for this type of application for many years. However...this chromatogram is presenting some challenges due to some non-specific interactions (I believe)....hence my request to the group to see if anyone has any first-hand tips/tricks.
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ChaoC

USA
185 Posts
Posted - 05/11/2023 :  09:25:25 AM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
Hi Chris,

Thank you for reaching out to us on the forum. We wanted to let you know that OriginLab support have sent you an email and created a ticket in response to your inquiry. Please check your inbox for our message. If you have any further questions or concerns, feel free to reply to the ticket and we'll be happy to assist you further.

Thank you,

Chao
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aplotnikov

Germany
169 Posts
Posted - 05/11/2023 :  5:11:22 PM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
quote:
I am pretty familiar with the complexity of the situation and I've been using Origin for this type of application for many years.

And still asking about the methods to describe peak tailing? Hmmmm...
quote:
However...this chromatogram is presenting some challenges due to some non-specific interactions (I believe)...

15 years ago I tried to play with peak parameters describing peak tailing for different proteins in SEC in order to find any correlations between peak shape and the protein nature and/or to distinguish between different protein forms using various deconvolution procedures. Unfortunately the reproducibility of the peak shape was extremely poor - I could perfectly approximate any peak by an appropriate function or by convolution of these functions, but the variation of parameters was terrible revealing no correlation with protein nature depending rather on the column prehistory. I assume, you have a similar situation. That is why I am so sceptic.
My experience tells me, that the right way is to try to avoid the non-specific interactions instead of to describe or to consider them.

Nevertheless I wish you good luck with the kind support of OriginLab.
Edited by - aplotnikov on 05/11/2023 5:23:01 PM
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tombinny1

1 Posts
Posted - 05/13/2023 :  05:11:41 AM  Show Profile  Edit Reply  Reply with Quote  View user's IP address  Delete Reply
Thanks for your guidlines. I am happy a lot.
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