One-electron reduction potential of m-AMSA+[9-(2-methoxy-4-methylsulphonylaminoanilino)acridinium] as measured by pulse radiolysis

Abstract

The absorption spectrum of one-electron reduced m-AMSA⁺ has been measured by pulse radiolysis. The radical species formed, m-AMSA˙, is readily oxidized by oxygen, flavin mononucleotide, and triquat; m-AMSA⁺ itself acts as an oxidant of the one electron reduced species of nicotinamide adenine dinucleotide. The one-electron reduction potential of the m-AMSA⁺/m-AMSA˙ couple at pH 7, E¹₇, has been determined to be –803 ± 10 mV (vs. NHE) by studying the equilibrium established between m-AMSA⁺/m-AMSA˙ and a low-potential bipyridinium compound used as a redox indicator.