US EPA

611638 

Journal Article 

UV direct photolysis of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) in aqueous solution: Kinetics and mechanism 

Lee, C; Yoon, J 

2008 

Yes 

Journal of Photochemistry and Photobiology A: Chemistry
ISSN: 1010-6030
EISSN: 1873-2666 

197 

2/3 

232-238 

10.1016/j.jphotochem.2007.12.030 

WOS:000256780100014 

https://linkinghub.elsevier.com/retrieve/pii/S1010603008000154
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Abstract: The direct photolysis of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) in aqueous solution was investigated under monochromatic ultraviolet (UV) irradiation at 254nm. ABTS was found to be directly photolyzed by UV irradiation to yield the one-electron oxidized radical, ABTS ⁺, which is a blue-green colored persistent radical species that has strong visible absorption bands. The photochemical production of ABTS ⁺ was strongly dependent on the solution pH and the presence of dissolved oxygen. The presence of dissolved oxygen increased the quantum yields at pH 3, whereas it inhibited the production of ABTS ⁺ at pH 6.5. Spectrophotometric and spectrofluorometric data indicated that ABTS photolysis may occur as a result of the transfer of one-electron between the singlet excited state and the ground state of ABTS. Observations made during UV/H2O2 experiments with ABTS suggested that the dependence of the photoloysis of ABTS on the solution pH and the presence of dissolved oxygen is related to the role of the hydroperoxyl/superoxide radical (HO2 loc="post">2 ^{−}), which appears to be formed via a secondary reaction of the reduced intermediate of ABTS with dissolved oxygen. The proposed photolytic reactions were supported by the observed stoichiometry between the amount of ABTS ⁺ radicals produced and the amount of ABTS molecules decomposed. [Copyright 2008 Elsevier] Copyright of Journal of Photochemistry & Photobiology A: Chemistry is the property of Elsevier Science Publishers B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts) 

PHOTOSYNTHETIC oxygen evolution; PHOTOCHEMISTRY; CHEMISTRY, Physical & theoretical; PHOTOBIOLOGY