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Indigo Carmine degradation by hypochlorite in aqueous medium monitored by electrospray ionization mass spectrometry
Author(s) -
de Urzedo Ana P. F. M.,
Nascentes Clésia C.,
Diniz Maria E. R.,
Catharino Rodrigo R.,
Eberlin Marcos N.,
Augusti Rodinei
Publication year - 2007
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.3037
Subject(s) - indigo carmine , chemistry , aqueous solution , electrospray ionization , hypochlorite , mass spectrometry , electrospray , nuclear chemistry , photochemistry , chromatography , inorganic chemistry , organic chemistry
The degradation of the dye Indigo Carmine by hypochlorite in aqueous solution was monitored by electrospray ionization mass spectrometry in the negative ion mode (ESI(—)‐MS). Hypochlorite was highly efficient in removing the color of aqueous solutions of the dye. ESI(—)‐MS monitoring showed that concomitant with the Indigo Carmine consumption two transient species appeared (detected as doubly charged anions) probably formed via a net insertion of two hydroxyl groups at the exocyclic CC bond followed by the incorporation of two (mainly) or one oxygen atoms at the indolic rings of the dye. Structures of these products were proposed based on the ESI(—)‐MS/MS data and high accuracy mass measurements. These two transient intermediates quickly decomposed, both in the condensed and in the gas phase, to yield mono‐charged anions. Based on these results, a route for the Indigo Carmine degradation by hypochlorite in aqueous solution has been proposed. Copyright © 2007 John Wiley & Sons, Ltd.