Creating a Peak Table
Defining the Retention Index and the Kovats Index

(Ret. Index and Kovats Index columns)

Retention indexes can be used to generate generally comparable retention times. The Retention Index and the Kovats Index are mainly used in GC to correct retention time variations. They are calculated based on the variables you enter for certain marker peaks in the peak table of the QNT Editor.

To define the retention index

1. Determine one or several peaks to be used as marker peaks.

2. In the Ret. Index column of these peaks, enter a value (usually 100, 200, 300 etc.). The column is 'empty' by default. The values must be in ascending order , i.e., either leave the next field empty or enter any value above the value for the previous peak.

   The RI values of all other peaks remain empty; they are calculated by means of interpolation.

To enter different values for the individual channels, select Columns > Duplicate Column on the Edit or the context menu to duplicate the column.

To define the Kovats index

1. On the General tab page of the QNT Editor, enter a Dead Time. The Kovats index is calculated using the adjusted retention times and cannot be calculated if no dead time is defined.

2. Determine one or several peaks to be used as marker peaks.

3. In the Kovats Index column of these peaks, enter a value. The column is 'empty' by default. The values must be in ascending order , i.e., either leave the next field empty or enter any value above the value for the previous peak.

   The KI values of all other peaks remain empty; they are calculated by means of interpolation.

To enter different values for the individual channels, select Columns > Duplicate Column on the Edit or the context menu to duplicate the column.