Artículo
Reaction of β-carotene with nitrite anion in a homogeneous acid system. An electron paramagnetic resonance and ultraviolet-visible study
Mendiara, Sara Noemí; Baquero, Romina Paola; Katunar, Maria Rosa
; Mansilla, Andrea Yamila
; Perissinotti, Luis José
Fecha de publicación:
06/2009
Editorial:
Springer Wien
Revista:
Applied Magnetic Resonance
ISSN:
0937-9347
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
Ultraviolet and visible spectroscopy was applied to characterize and to measure the concentration of β-carotene dissolved in a dioxane and water mixture. The reaction of β-carotene in the presence of nitrite anion and acid medium was studied at different temperatures. The reaction systems were homogeneous and were kept anaerobic. Pseudo-first-order rate constants in respect of β-carotene were measured in the range from 293 to 313 K and pH 5.8 ± 0.2. The energy of activation was calculated to be E a = 67.2 ± 3.4 kJ/mol. We interpolate a value that may have biological interest, k β-carotene(310 K) = (9.70±0.78) · 10−3 s−1, in the presence of 9.3 · 10−3 M nitrite anion. Electron paramagnetic resonance spectroscopy was applied to characterize and quantify a persistent intermediate radical generated in the reaction system described. The recorded spectra showed triplet-type signals with a peak-to-peak value of 12.7 G. Nearly the same triplet radical-type intermediates were detected when studying the following reaction systems in pure dioxane: nitrogen dioxide (NO2)/β-carotene, nitric oxide (NO)/β-carotene and NO/NO2/β-carotene. Therefore, we proposed that the nitrogen oxides have also been intermediates in the reaction system of β-carotene, nitrite anion and acid medium, in the dioxane and water mixture. A mechanism was proposed and checked by employing the chemical kinetics simulation. The explanations developed would lead to a better understanding of the behavior of carotenoids in the presence of nitrite anion and nitrogen oxides.
Palabras clave:
Carotene
,
Nitrite Anion
,
Epr
,
Uv-Visible Spectroscopy
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Identificadores
Colecciones
Articulos(IIB)
Articulos de INSTITUTO DE INVESTIGACIONES BIOLOGICAS
Articulos de INSTITUTO DE INVESTIGACIONES BIOLOGICAS
Articulos(INTEMA)
Articulos de INST.DE INV.EN CIENCIA Y TECNOL.MATERIALES (I)
Articulos de INST.DE INV.EN CIENCIA Y TECNOL.MATERIALES (I)
Citación
Mendiara, Sara Noemí; Baquero, Romina Paola; Katunar, Maria Rosa; Mansilla, Andrea Yamila; Perissinotti, Luis José; Reaction of β-carotene with nitrite anion in a homogeneous acid system. An electron paramagnetic resonance and ultraviolet-visible study; Springer Wien; Applied Magnetic Resonance; 35; 4; 6-2009; 549-567
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