Add a custom baseline (Data Analysis)
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Add a custom baseline

  1. To preview the new custom baseline, click in the toolbar.

    2. The following figures show a typical baseline for individual peaks, versus a long-range baseline that encompasses numerous coeluded peaks.

     

    Example: Chromatogram without custom baseline

     

    Example: Chromatogram with custom baseline

  2. Move the mouse over the lines, and drag them to the required start and end position.

    3. Make sure that you start and stop the custom baseline in a section where no peaks are expected. If the start or end position is located within a peak, that peak may be cut off.

    To check the new timed integration events that you create for the section, click . The timed events are then visible in the chromatogram. The type of event depends on the integrator that you selected in step 1:

    • EZChrom integrator: One Manual baseline event is added, with start time and stop time corresponding to the selected section.

    • ChemStation integrator: A total of three events are added.

      One Set low baseline from range is added where the selected section begins.

      One Set low baseline from range and one Use baseline from range are added where the selected section ends.

  3. To save the new custom baseline, click next to the Add custom baseline icon in the toolbar.

    4. or To discard the changes, click without saving the changes first.

  4. Check the new integration events that you have created for the section. If timed events are not displayed, click to show them.

  5. ChemStation integrator only: Consider adjusting the values of the Set low baseline from range events.

    6. The value of the Set low baseline from range event is the time interval around the event time. It is used for statistics on baseline points. If peaks partially intrude into this interval, consider reducing the value. Reducing the value may improve the reproducibility in other chromatograms.

    To edit a value:

    • Use the integration events table in step 3

      or

    • Keep the [CTRL] key pressed while moving the mouse over an existing integration event. When the command hint Click to Edit Value is shown, click the timed integration event, and provide the new value.

  6. To adjust the section after saving it, edit the corresponding integration events.

    7. If you use the ChemStation integrator, make sure that you edit both events at the end of the section, Set low baseline from range and Use baseline from range.