Spectra PDA extracted

I have an issue trying to plot extracted PDA spectra. 
We have a method that registers spectra from 200nm to 700nm and then we extract the spectra at a fixed wavelength. Then this spectra is plotted with a standard to compare both and say whether they are the same substance or not.

If we process the channel with a processing with a fixed wavelength we cannot get the spectra so we have to do it manually. If someone knows how to do it I really appreciate it.

Thanks!

Comments

  • Hi PMJ,

    Just some clarifying questions to start with so that we can understand the problem a little better.  If I read this right, you are extracting a single wavelength chromatogram (2d data) from your PDA spectrum (3d data) and identifying it by retention time.  Is that correct?

    There is an excellent article on the correct way to extract data from 3d data in the Waters Knowledge Base here.

    Good luck! 

    Marc
  • Can you derive a channel in your method set called Single Wavelength PDA, pick the wavelength you extract from and add that to the channel table, linked with a suitable processing method. Then process your sample set with this method set to generate the result you need. 
  • I know how to do it but then I get the following issue: I do not get the spectra.
    Our work is based on overlap the spectra got from the standard and the samples to say whether they have the same shape or not.
    So it is not only getting the chromatogram at a fixed wavelength but overlapping the spectra