Detection and Quantification of Nitric Oxide Using Electron Magnetic Resonance Spectroscopy

Abstract

The use of electron magnetic resonance (EMR) spectroscopy, also known as electron paramagnetic resonance (EPR) or electron spin resonance (ESR) spectroscopy, to detect and quantify the paramagnetic molecule nitric oxide, NO, in model systems, cells, and living organisms is reviewed. The physical basis for EMR spectroscopy and the information available from this method are presented. Since free NO is not detectable by EMR in solution, compounds and methods for trapping and stabilizing NO in paramagnetic EMR-detectable complexes, often with NO bound to Fe(II), are summarized, as are other indirect methods for quantifying NO with EMR spectroscopy. Sample manipulation, data collection, and data analysis are discussed, with particular reference to EMR-detectable NO complexes. Examples are presented from the author′s own work that Illustrate different applications of EMR spectroscopy for detection and quantification of NO. Finally, EMR is compared to other methods for the determination of NO in biological and model systems.