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Fourier Transform EPR Spectroscopy of Trityl Radicals for Multifunctional Assessment of Chemical Microenvironment
Author(s) -
Bobko Andrey A.,
Dhimitruka Ilirian,
Zweier Jay L.,
Khramtsov Valery V.
Publication year - 2014
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201310841
Subject(s) - electron paramagnetic resonance , chemistry , radical , fourier transform infrared spectroscopy , spectroscopy , analytical chemistry (journal) , relaxation (psychology) , aqueous solution , photochemistry , paramagnetism , nuclear magnetic resonance , organic chemistry , chemical engineering , psychology , social psychology , physics , quantum mechanics , engineering
Pulse techniques in electron paramagnetic resonance (EPR) allow for a reduction in measurement times and increase in sensitivity but require the synthesis of paramagnetic probes with long relaxation times. Here it is shown that the recently synthesized phosphonated trityl radical possesses long relaxation times that are sensitive to probe the microenvironment, such as oxygenation and acidity of an aqueous solution. In principle, application of Fourier transform EPR (FT‐EPR) spectroscopy makes it possible to acquire the entire EPR spectrum of the trityl probe and assess these microenvironmental parameters within a few microseconds. The performed analysis of the FT‐EPR spectra takes into consideration oxygen‐, proton‐, buffer‐, and concentration‐induced contributions to the spectral shape, therefore enabling quantitative and discriminative assessment of pH, pO 2 , and concentrations of the probe and inorganic phosphate.