Substituted pyridine and their derivatives have emerged as novel disperse dyes and attracted considerable interest owing to their inherent antioxidant and biological activities, depending upon the chromophoric
and auxoxhrome groups [15-17].
This is a characteristic behavior of HS substances and occurs due to the overlapping of peaks relative to different chromophoric
groups, such as aromatic structures located in several points of the macromolecule and in several forms of conjugation of double bonds with simple bonds, occurring the splinting of the peaks and the junction of the same in a misshapen spectrum (McCarthy & Rice, 1985).
Wang, "Optical properties and spatial distribution of chromophoric
dissolved organic matter (CDOM) in Poyang lake, China," Journal of Great Lakes Research, vol.
Decolorization through chemical treatment with ozone, Fenton's reagent, and [H.sub.2][O.sub.2]/UV leads to color reduction due to breaking of the conjugation and or bonds in chromophoric
dissolved organic matter (CDOM) naturally occurring in all aquatic environments is colored and contains materials of different molecular sizes (MSs).
However, the number of chromophoric
groups that generated absorption peaks in the spectrum was so large that it was difficult to identify groups clearly.
The *OH radical can attack the chromophoric
group of dye and initiate the oxidation of reactive dye by abstraction of hydrogen atom and electrophilic addition consecutively involving several degradation mechanisms, during which aromatic intermediates and inorganic ions are formed .
The most continuous and well-studied supply stems from coastal photochemical production where chromophoric
dissolved organic matter absorbs sunlight and ultimately yields a variety of oxygen radical species (O'Sullivan et al., 2005).
Diester-based HALS would have no initial action in suppressing the formation of paraquinone chromophoric
groups, but would be effective in capturing the free radicals formed and reduce the formation of hydroquinones, thus reducing photobleaching.
The results obtained using a commercially available [PLA.sub.2] assay kit, in which a synthetic, chromophoric
phospholipid is used as a substrate, should be interpreted carefully, since some [PLA.sub.2]s are unable to hydrolyze it efficiently.
Another characteristic of the chemical structure of PHB is the presence of a chromophoric
carbonyl group .
Moreover, the changes in the content of chromophoric
groups (e.g., carbonyl, alkene, and phenyl) and auxochromophoric groups (e.g., hydroxyl and carboxyl groups) likely explain the dark color of the treated wood.