After you add deconvoluted spectra to the Library, you can select two spectra to compare in a mirror plot on the Spectra Comparison page.

Prerequisites

  1. For an intact mass analysis experiment, you have processed your experiment and are viewing the Process and Review page.

Procedure

  1. From the Process and Review page, select the Spectra Comparison tab to open the Spectra Comparison page.
  2. The Spectra Comparison page opens, displaying the Deconvoluted Spectra Library table at the top of the page and the Mirror Plot pane (currently empty) at the bottom of the page.
  3. Each row in the Deconvoluted Spectra Library table displays information about a particular deconvolved spectrum added to the Library.
  4. See Spectra Comparison page parameters.
  5. In the Deconvoluted Spectra Library table, select the checkboxes for the two deconvolved spectra you want to compare. You can only select two spectra at a time.
  6. At the bottom of the Spectra Comparison page, the Mirror Plot pane displays a mirror plot with one spectrum in the negative direction and another spectrum in the positive direction.
  7. image/svg+xml First spectrum Second spectrum
    Mirror Plot pane on the Spectra Comparison page
  8. At the top and bottom of the Mirror Plot pane, the name, raw data file name, and NL (normalized level) value is displayed for each spectrum.
  9. The mirror plot is scaled to 100 percent in both directions, but the actual intensities of the spectra can be completely different.
  10. You can view the different intensities of the peaks in each spectrum by referring to the NL values displayed for each spectrum.
  11. If the two compared spectra do not cover the same mass range, the application automatically expands the range in the mirror plot to include the lowest limit and the highest limit of both spectra.
  12. For example, if one spectrum has a range of m/z 15,000 to 100,000 and the other spectrum has a range of m/z 25,000 to 160,000, the application expands the range to m/z 15,000 to 160,000 in the mirror plot.
  13. (Optional) Right-click in the Mirror Plot pane and select Zoom In to enlarge the plot or drag the cursor beneath the part of the spectrum that you are interested in to enlarge the area.
  14. See Mirror Plot pane commands.
  15. Enlarged mirror plot
    Enlarged mirror plot
  16. (Optional) To determine whether two spectra are comparable, you can view the deconvolution parameters used to generate each spectra, one spectrum at a time. In the Deconvoluted Spectra Library table, select the row (not checkbox) for one spectrum in the Deconvoluted Spectra Library table and select the Show Details button to the right of the table.
  17. The Spectrum Information box appears and displays the deconvolution parameters used to generate the selected spectrum.