Understanding Variations in Ferrate Detection through the ABTS Method in the Presence of Electron-Rich Organic Compounds.
Environ Sci Technol
; 58(32): 14575-14584, 2024 Aug 13.
Article
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| MEDLINE
| ID: mdl-39094193
ABSTRACT
The chromogenic reaction between 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) and ferrate [Fe(VI)] has long been utilized for Fe(VI) content measurement. However, the presence of electron-rich organic compounds has been found to significantly impact Fe(VI) detection using the ABTS method, leading to relative errors ranging from â¼88 to 100%. Reducing substances consumed ABTSâ¢+ and resulted in underestimated Fe(VI) levels. Moreover, the oxidation of electron-rich organics containing hydroxyl groups by Fe(VI) could generate a phenoxyl radical (Phâ¢), promoting the transformation of Fe(VI) â Fe(V) â Fe(IV). The in situ formation of Fe(IV) can then contribute to ABTS oxidation, altering the ABTSâ¢+Fe(VI) stoichiometry from 11 to 21. To overcome these challenges, we introduced Mn(II) as an activator and 3,3',5,5'-tetramethylbenzidine (TMB) as a chromogenic agent for Fe(VI) detection. This Mn(II)/TMB method enables rapid completion of the chromogenic reaction within 2 s, with a low detection limit of approximately 4 nM and a wide detection range (0.01-10 µM). Importantly, the Mn(II)/TMB method exhibits superior resistance to reductive interference and effectively eliminates the impact of phenoxyl-radical-mediated intermediate valence iron transfer processes associated with electron-rich organic compounds. Furthermore, this method is resilient to particle interference and demonstrates practical applicability in authentic waters.
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Texto completo:
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Banco de datos:
MEDLINE
Asunto principal:
Oxidación-Reducción
/
Electrones
Idioma:
En
Revista:
Environ Sci Technol
Año:
2024
Tipo del documento:
Article
País de afiliación:
China