Sample Ripening through Nanophase Separation Influences the Performance of Dynamic Nuclear Polarization
Year: 2018
Type: article
Abstract: Mixtures of water and glycerol provide popular matrices for low-temperature spectroscopy of vitrified samples. However, they involve counterintuitive physicochemical properties, such as spontaneous nanoscopic phase separations (NPS) in solutions that appear macroscopically homogeneous. We demonstrate that such phenomena can substantially influence the efficiency of dynamic nuclear polarization (DNP) by factors up to 20 % by causing fluctuations in local concentrations of polarization agents (radicals). Thus, a spontaneous NPS of water/glycerol mixtures that takes place on time scales on the order of 30-60 min results in a confinement of polarization agents in nanoscopic water-rich vesicles, which in return affects the DNP. Such effects were found for three common polarization agents, TEMPOL, AMUPol and Trityl.
Institutions: Centre National de la Recherche Scientifique, Université Paris Sciences et Lettres, École Normale Supérieure - PSL, Sorbonne Université, Laboratoire des Biomolécules, Université de Lille, Laboratoire de Spectroscopie pour les Interactions, la Réactivité et l'Environnement, Institut de Biologie Paris-Seine
Language: English
Subfield: Spectroscopy
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
Funder: European Research Council
OpenAlex ID: W2789489072