Field-Cycled Proton-Electron Double-Resonance Imaging (FC-PEDRI) of 15N Nitoxice Free Radicals at 1.1 mT EPR Field

Abstract

Field-Cycled Proton-Electron Double-Resonance Imaging (FC-PEDRI) was used toimage 15N nitroxide free radicals by saturation of ?? Electron Paramagnetic Resonance (EPR)transitions. To locate EPR ?? transitions, field-cycled dynamic nuclear polarization (FC-DNP)experiments were performed with a 1 mM 15N D17 TEMPOL solution sample (a 15Nnitroxide system) at an EPR frequency of 52.52 MHz. FC-PEDRI experiments wereperformed at a low magnetic field of 1.1 mT for EPR with a proton NMR detection field of59 mT. The SNR of the difference image was larger than that using 14N nitroxide.