Extract an MS background spectrum
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Extract an MS background spectrum

Preparations

  • The injection is linked to a processing method that supports manual MS spectra extraction (method configurations MS or LC/MS Sample Purity).

  • To be able to carry out the procedure as described, you need the privileges Data Processing > Do manual spectrum extraction and Processing Method > Edit spectrum extraction parameters . Privileges are configured in the Control Panel.

  • If the project enforces method approval, the method status must be Generic. For details, see Method approval.

  1. Make sure the spectrum extraction tool is activated in the toolbar

  2. Move the mouse directly over the signal so that the Background hint is shown.

    Spectrum extraction cursor for background spectrum
    Figure Spectrum extraction cursor for background spectrum

  3. At the required position in the chromatogram, click in the circle below the Background hint (but not on the dot in the center of the circle).

    OR: To extract an average spectrum over a time range, click in the circle and drag the cursor over the required range.

  4. When asked for confirmation, click or press ENTER to confirm the spectrum extraction. The spectrum extraction will occur without confirmation if you cleared the corresponding check box in the Chromatogram Properties.

    The extracted spectrum is shown in the MS Spectrum window, and it is listed under the details for the individual injection in the injection tree.

    NOTE

    Extracting a background spectrum changes the method settings in the Extraction > Spectrum section in the MS tab.

    The time point or time range used for the background spectrum extraction is set as External time range. Arbitrary spectra and peak spectra that use an external time range will now use the new time range.

  5. Optional: In the Extraction > Spectrum section of the method, in the MS tab, configure a background mode for arbitrary spectra or peak spectra.

    When you extract other MS spectra, background spectra will then automatically be subtracted as configured. The time point or time range used for subtraction is shown in the spectrum name.

  6. Save the data.

    Extracted spectra are saved together with the data.

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