The direct photolysis of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) in aqueous solution was investigated under ultraviolet (UV) irradiation. It was newly found that ABTS is directly photolyzed to yield the one-electron oxidized radical, ABTSㆍ, the possible mechanisms of dissolved oxygen. From the observed photolytic behaviors, the possible mechanisms of ABTS photolysis were proposed. The proposed photolytic reactions were supported by the observed stoichiometry between the amounts of ABTSㆍdicals produced and ABTS molecules decomposed.
The direct photolysis of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) in aqueous solution was investigated under ultraviolet (UV) irradiation. It was newly found that ABTS is directly photolyzed to yield the one-electron oxidized radical, ABTSㆍ+, which is a blue-green colored persistent radical species with strong visible absorption bands. The photochemical production of ABTSㆍ+ was strongly dependent on the solution pH and the presence of dissolved oxygen. From the observed photolytic behaviors, the possible mechanisms of dissolved oxygen. From the observed photolytic behaviors, the possible mechanisms of ABTS photolysis were proposed. The proposed photolytic reactions were supported by the observed stoichiometry between the amounts of ABTSㆍ+ radicals produced and ABTS molecules decomposed.