Fourier transform EPR spectroscopy of trityl radicals for multifunctional assessment of chemical microenvironment.
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, pO2, and concentrations of the probe and inorganic phosphate.
Dorothy M. Davis Heart & Lung Research Institute and Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, Department of Internal Medicine, The Ohio State University, 201 HLRI, 473 W 12th Ave, Columbus, OH 43210 (USA).
Andrey A
AA
Bobko
Ilirian
I
Dhimitruka
Jay L
JL
Zweier
Valery V
VV
Khramtsov
D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000138:chemical synthesis / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D015394:Molecular Structure; D009943:Organophosphorus Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D010710:Phosphates / Q000737:chemistry
D005609:Free Radicals; D009943:Organophosphorus Compounds; D010710:Phosphates; D010100:Oxygen
EPR spectroscopy; biosensors; radicals; relaxation times