One of a few stable and commercially available organic nitrogen radicals and has a UV-vis absorption maximum at 515 nm. Upon reduction, the solution color fades. The reaction progress is conveniently monitored by a spectrophotometer. Even though not physiologically relevant, DPPH is still utilized in antioxidant research due to its simple reaction system, which involves only the direct reaction(s) between the radical and the antioxidant(s), and have no other interference such as enzyme inhibition or the presence of multiple radicals.
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