Enter the retention factor of the second peak and the retention factor of the first peak into the Selectivity Factor Calculator. The calculator will evaluate the Selectivity Factor.

## Selectivity Factor Formula

The following two example problems outline the steps and information needed to calculate the Selectivity Factor.

a = K2/ K1

Variables:

• a is the Selectivity Factor ( )
• K2 is the retention factor of the second peak
• K1 is the retention factor of the first peak

## How to Calculate Selectivity Factor?

The following steps outline how to calculate the Selectivity Factor.

1. First, determine the retention factor of the second peak.
2. Next, determine the retention factor of the first peak.
3. Next, gather the formula from above = a = K2/ K1.
4. Finally, calculate the Selectivity Factor.
5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem :

Use the following variables as an example problem to test your knowledge.

retention factor of the second peak = 3

retention factor of the first peak = 2.5

a = K2/ K1 = ?