Quantitation of Spin Concentration of Some Free Radicals.
NAVAL AIR DEVELOPMENT CENTER WARMINSTER PA CREW SYSTEMS DEPT
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A simple method for the quantitation of small free radicals has been developed using nitrosyl disulfonate and porphyrexide as model compounds. The double integral of the electron paramagetic resonance EPR signal of solutions of each free radical was obtained and correlated with optical density measurements. In this way, curves of normalized area by EPR versus concentration of radical were obtained and shown to be linear. Titrations of these radical solutions with dithiothreitol or alpha-thioglycerol caused a linear decrease in both the measured optical density and the measured doubly integrated EPR signals. A concept was developed called radical equivalency. A reagent which provides n one-electron reducing sites per molecule has a radequivalency equal to n times its molarity. Author
- Physical Chemistry