How To Determine Concentration of an Impurity in HPLC with the Relative Response Factor – RRF.

The concentration can be calculated once you have values for the following two equations:

     Response Factor (RF) = Peak Area / Concentration

     Relative Response Factor (RRF) = RFimpurity / RFAPI

You can use RRF and RFAPI to solve for RFimpurity. Then you can use the measured Peak Area of the Impurity to solve for its Concentration.