Reaction Restrictions can be used to change the default settings of the ionization method and of the basic fragmentation and rearrangement mechanisms. The m/z precision of calculated fragments can be set in the Options | Mass Settings menu item. The isobaric differentiation of calculated fragments can be set in the Resolution Settings

To start the Reaction Restrictions dialog window:

• Choose the Options | Reaction Restrictions menu item.

The Reaction Restrictions window contains six tabs: Knowledge Base, Ionization & Cleavage, H-Rearrangement, Resonance, Additional and Sizes.

If you have established restriction settings that you wish to apply frequently to a specific compound class, you can save the current reaction restrictions to a file (*.rrs file extension) by clicking the Save button in the Reaction Restrictions dialog box. When you open a reaction restriction file by clicking the Open button, the dialog window adopts the restrictions saved in the file. You must then press the OK button, to make these restrictions active in Mass Frontier.