EPR testing of the concentration of paramagnetic centers using standards

A calculation model for the evaluation of the concentrations of paramagnetic centers in specimens using their electron paramagnetic resonance spectra in the form of single derivatives of resonance curves is developed. It is shown that using a correcting factor to account for differences of the shapes of the resonance curves of standards, which are based on a polycrystalline radical of the alpha, alpha'-diphenyl-beta-picrylhydrazyl type, and tested objects allows the error in the evaluation of the paramagnetic-center concentration to be reduced to a practically acceptable level of 30%.