Direct separation of intra- and inter-molecular contributions in pulse dipolar EPR experiments

RESUMO

We present a direct method of separating intra- (form factor) and inter-molecular (background) contri- butions in pulse EPR dipolar spectroscopy (PDS) experiments. The form factor/background separation is accomplished by rearranging data measured at two different biradical concentrations, without any fitting fundamentally required. This new data processing method allows to analyse PDS data from spin concen- trated samples for which background separation was previously unrealistic. In particular, the presented method would be of high importance for studies of spin labeled biomolecules, especially in respect to the liquid-liquid phase separation (LLPS). Furthermore, we propose a simple measurement and data processing protocol to separate the PDS contributions from each phase in LLPS samples. The protocol for the form factor/background separation for RIDME experiment is also discussed