Use relative retention times (RRT)
This procedure explains how you can use relative retention times (RRT). For many applications RRT values can be retrieved from literature or reference tables. To use them, you configure an RRT reference compound and one or more associated compounds (see figure below).
Example: Relative retention times in the identification parameters
Prerequisites
To be able to carry out the procedure as described, you need the privilege Processing Method > Edit identification 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.
In the Processing Method window, select Compounds > Identification.
Select the General tab.
Select the Use RRT reference compounds check box.
Select the Compound Table tab.
Create a new entry for each required RRT reference compound, or select an existing compound as reference. For each RRT reference compound:
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Select the Is RRT ref. check box.
Enter the expected RT.
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For the associated compound:
Under Associated RRT reference, select the correct reference compound.
Under RRT, enter the RRT value from literature or reference tables.
The columns Is RRT ref., Associated RRT ref., and RRT become visible in the compound table.
The expected RT for the associated compound is then automatically calculated and used for identification.
If you change the expected RT of the RRT reference, the expected RT of the associated compound will automatically be recalculated, The RRT values will not change.
If you change the expected RT of the associated compound, the RRT value of the associated compound will automatically be recalculated. Nothing changes for the RRT reference.
For not identified peaks, there is no associated compound. In this case, the first RRT reference compound is used to calculate the RRT value.
For details on how the application calculates the values, see Calculations for relative retention times (RRT).