Enhancement of carboxylic acid degradation with sulfate radical generated by persulfate activation

2010 ◽  
Vol 61 (5) ◽  
pp. 1221-1226 ◽  
Author(s):  
J. Criquet ◽  
P. Nebout ◽  
N. Karpel Vel Leitner

The aim of this work was to investigate the generation of sulfate radical for the removal of two carboxylic acids in aqueous solution: acetic and citric acids. From photochemical and radiolytic processes, kinetics of the degradation of these two carboxylic acids was studied as a function of the pH of the solution. It was shown that the maximum of acetic acid degradation occurred at pH 5. Above this pH, competitive reactions with the carbon mineralized inhibit the reaction of with the solute. In the case of citric acid, pH has only a little effect on the kinetic of citric acid degradation. The determination of mineralization yields shows several differences depending on carboxylic acids and pH. The degradation of both carboxylic acids was also studied in the radiolysis process whether with or without persulfate addition. A comparison of the processes of sulfate radical production is presented.

2020 ◽  
Vol 21 (22) ◽  
pp. 8834
Author(s):  
Natalia Drobnicka ◽  
Katarzyna Sutor ◽  
Agnieszka Kumorkiewicz-Jamro ◽  
Aneta Spórna-Kucab ◽  
Michał Antonik ◽  
...  

Herein, the generation of decarboxylated derivatives of gomphrenin pigments exhibiting potential health-promoting properties and the kinetics of their extraction during tea brewing from the purple flowers of Gomphrena globosa L. in aqueous and aqueous citric acid solutions were investigated. Time-dependent concentration monitoring of natural gomphrenins and their tentative identification was carried out by LC-DAD-ESI-MS/MS. The high content of acylated gomphrenins and their principal decarboxylation products, 2-, 15-, 17-decarboxy-gomphrenins, along with minor levels of their bidecarboxylated derivatives, were reported in the infusions. The identification was supported by the determination of molecular formulas of the extracted pigments by liquid chromatography coupled with high-resolution mass spectrometry (LCMS-IT-TOF). The influence of plant matrix on gomphrenins’ stability and generation of their derivatives, including the extraction kinetics, was determined by studying the concentration profiles in the primary and diluted infusions. Isolated and purified acylated gomphrenins from the same plant material were used for the preliminary determination of their decarboxylated derivatives. The acylated gomphrenins were found to be more stable than nonacylated ones. Citric acid addition had a degradative influence on natural gomphrenins mainly during the longer tea brewing process (above 15 min); however, the presence of plant matrix significantly increased the stability for betacyanins’ identification.


2000 ◽  
Vol 48 (2) ◽  
pp. 208-210
Author(s):  
Yasuo YOSHIHASHI ◽  
Etsuo YONEMOCHI ◽  
Midori MAKITA ◽  
Shigeo YAMAMURA ◽  
Eihei FUKUOKA ◽  
...  

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