An HPLC method with dual detectors was developed to measure the extinction coefficients.
The MEC was solved by Beer’s law (A = εcl), with A and c obtained from DAD and CLND.
The method measures MEC accurately even when the sample is impure or in a mixture.
Compared to the only available method, our method is sample sparing and easy to implement.
The MEC has been successfully used for DAR characterization of ADCs in drug discovery.