Peak Evaluation details

Peak evaluation provides optional user defined calculations on available peak data of a data object. Any calculation results based on peak data can be added to your spectral data. Calculation results will be presented as additional columns in the peak table. Whenever the user uses the Find Peaks operation to create a peak table for the data object, additional calculation results are calculated as well and presented in the peak table.

The Peak Evaluation command is available in the Mathematics menu.

Peak Evaluations are data type dependent! Peak evaluation methods are useful for particular data types. Therefore, several peak evaluation methods can be stored by data type. Only those of the active data type will be applied to your data.

Add or Edit Peak Evaluation

To add new peak evaluation methods or edit existing evaluation methods, please follow the steps described below. If you want to edit an existing evaluation method, select it from the list and continue with step 5 of the description below:

1. From the Mathematics menu, select the Peak Evaluation command.
   The Peak Evaluation dialog opens and shows existing evaluation methods.
   
   

2. Click the Add button to add a new peak evaluation method.
   A dialog opens, where you must enter a new name for the peak evaluation method:
   
   

3. Enter a meaningful name for your peak evaluation method.

4. Click the OK button to create the new peak evaluation method.
   The new peak evaluation method will be transferred into the main dialog:
   
   

5. Click into the empty field beside the label Formula in the Evaluation Parameters.

6. Enter a user defined formula or click the button to open the formula editor.

7. In the formula editor, enter the particular evaluation formula. You might refer to any peak data and other spectral information in your calculations. Please refer to the "Peak Evaluation Formula Editor" section in the chapter "Dialogs" for details.

8. Click the OK button to save current peak evaluation methods and close the dialog.

Remove Peak Evaluation

1. From the Mathematics menu, select the Peak Evaluation command.
   The Peak Evaluation dialog opens and shows existing evaluation methods.
   
   

2. In the list of peak evaluations on the left, select the evaluation method you like to delete.

3. Click the Remove button.

4. Click the OK button to save current peak evaluation methods and close the dialog.

Show and Hide Peak Evaluation Results

Peak evaluation results are calculated automatically, whenever a peak table is created using the Find Peaks command. Results are shown in additional columns of the peak table. To show or hide these columns, please change the peak table column settings.

For details on this, please refer to the "Peak Table Display Options" section.

Peak Evaluation Example

A very simple example is the calculation of the extinction values of peaks in a UV spectrum. This can be done automatically with peak evaluation on creation of a peak table.

1. Add a peak evaluation formula as described above using the following formula for calculation of the extinction:

log (  Intensity[ x ] / #Peak.Height )

where

x: wavelength of your background Intensity

2. Then select the Find Peaks command in the mathematics menu.

3. Adjust the peak parameters in the Mathematics Tab.

4. Click the Calculate button.

The new peak table shows peak data and an additional column with extinction results: