Extract a UV spectrum with the spectrum extraction tool

The behavior of the spectrum extraction tool is configurable. To change the behavior, click in the Chromatograms window, and adjust the settings in the Spectrum extraction section. In the following procedure, all options are enabled.

Preparations

• The injection is linked to a processing method that supports manual UV spectra extraction (method configurations 3D UV Quantitative or LC/MS Sample Purity).

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

1. To automatically subtract background spectra: In the processing method, select the Extraction > Spectrum node (UV tab), and adjust the Background mode settings.

   • The background mode under Arbitrary spectra has an effect on spectra that you extract outside of a peak.

   • The background mode under Peak Spectra has an effect on spectra that you extract between peak start and peak end.

2. In the Chromatograms window, click in the toolbar to activate the spectrum extraction tool.

3. Move the mouse over the chromatogram. The cursor changes dynamically, for example, if you move it over a peak apex or a baseline.

   

   Figure Spectrum extraction cursor at peak apex

4. Click at the required position in the chromatogram.

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

5. 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.

   Confirmation dialog at peak apex

   Confirmation dialog at selected time point

   The extracted spectrum is shown in the UV Spectrum window.

   The time point or time range used for subtraction is shown in the spectrum name.

   The extracted spectrum is listed under the details for the individual injection in the injection tree.

   

6. Save the data.

   Extracted spectra are saved together with the data.