Paramagnet induced signal quenching in MAS–DNP experiments in frozen homogeneous solutions.

Highlights: [•] Paramagnet induced quenching and relaxation in MAS–DNP experiments. [•] Comparison of four fundamentally different polarizing agents. [•] Optimization of paramagnet concentration. [•] Cross effect biradicals are superior to monoradicals. [•] MAS mediates quenching equally for TOTAPOL and trityl. [ABSTRACT FROM AUTHOR]