Overlaying chromatograms and adjusting the x-axis individually

<p>We have a method where the main peak in the chromatogram shifts from run to run (maybe 2-3 minutes) depending on the run.</p><p>We often get requests from agencies, stability, etc. for overlays of chromatograms where they are just looking at the chromatography</p><p>and the retention time isn't relavent.  So they want to see the main peak overlay from several runs.  In our previous software</p><p>you could adjust the x-axis of each peak individually (i.e. change the offset for each overlay) so if the retention time shifted you could</p><p>adjust it so they lined up in the overlay.  Is there some way to accomplish the same thing in Empower?  We can always export</p><p>the raw data to excel but that isn't very convenient.</p><p></p><p>Thanks in advance for any help or ideas!</p><p></p><p></p><p>Chris</p>


  • Hello, I use this function.

    Select your Results and Compare.

    Now they are overlay in a new window.

    Press icon [Individual Plot]

    Press icon [Alignment markers]

    Move the markers on all you chromatograms, to align you peak of interest.

    Press icon [Align chromatograms]

    Now your peak of interst are align.

    Press icon [Compare Main Window]

    I think it is not very smart if you want to align and zoom on a area of the chromatogram.

    I hope it will help you.

  • Thanks but this doesn't really solve the problem.  I can align them in the individual plot but when I go back to compare they are not aligned.

    They look slightly aligned at full scale but if you zoom in at all they will not be aligned.  You can see my the sequence of pictures below.

    I am looking for aligned and zoomed as the overlays at full scale aren't very helpful.  Any other suggestions out there??

    Thank you,



    Individual Plots.jpg

    Unzoomed and Aligned.jpg


  • Yes I now is not working so good.

    You have to zoom chrom. before align them.