Detection of nitric oxide by electron paramagnetic resonance spectroscopy

Abstract

Electron paramagnetic resonance (EPR) spectroscopy has been used in a number of ways to study nitric oxide chemistry and biology. As an intrinsically stable and relatively unreactive diatomic free radical, the challenges for detecting this species by EPR are somewhat different than those for transient radical species. This review gives a basic introduction to EPR spectroscopy and discusses its uses to assess and quantify nitric oxide formation in biological systems.

PAMAM dendrimers functionalized with ruthenium nitrosyl as nitric oxide carriers

“…The detection of the nitric oxide released from ruthenium nitrosyl complexes after light irradiation was performed through EPR spectroscopy, using the NO spin trap 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO) [52,53]. Thus, a phosphate buffer solution (pH 7.4, 0.10 mol L…”

“…Thus, solutions containing trans-[Ru(NO)(NH 3 ) 4 (ina)] 3+ (attached or not to PAMAM G2) were irradiated at 355 nm in phosphate buffer (pH 7.4) in the presence of PTIO. This last compound is a well known nitric oxide spin trap [52,53]. PTIO reacts with NO yielding PTI, as illustrated in Fig.…”

“…4. Both PTIO and PTI are paramagnetic species, and therefore can be detected and distinguished through EPR spectroscopy [52,53]. Thus, performing the photochemical reaction for trans-[Ru(NO)(NH 3 ) 4 (ina)] 3+ and for G2/RuNO in the presence of PTIO, it was possible to detect the NO release from these compounds due to the observation of the signals related to the PTI species (Fig.…”

“…Thus, performing the photochemical reaction for trans-[Ru(NO)(NH 3 ) 4 (ina)] 3+ and for G2/RuNO in the presence of PTIO, it was possible to detect the NO release from these compounds due to the observation of the signals related to the PTI species (Fig. 5) [52,53]. The values obtained for the hyperfine splitting constant ( À1 CF 3 COOH/CF 3-COONa), and it was monitored through UV-Vis spectroscopy (Fig.…”

Nitric Oxide in Azospirillum and Related Bacteria: Production and Effects

“…The amount of energy absorbed is proportional to the amount of unpaired electrons in the sample, and the value of the external magnetic fi eld at which resonance occur, in a constant microwave frequency, is related to g , that is a spectroscopic factor characteristic of a given paramagnetic center. The shape and the hyperfi ne structure of the spectral line are also characteristic of a paramagnetic substance (Hogg 2010 ).…”