Here the introduction of
auxochrome like hydroxyl group which produce bathochromic effect and give rise to the 23 nm and 18 nm [[lambda].sub.max] value in [D.sub.4] with respect to [D.sub.7] and [D.sub.8].
All these have part of phenols and naphthols having hydroxyl group as
auxochrome group.
This method is based on the observation that the Coomassie Brilliant Blue G-250 exists in two different color forms, red (365 nm) and blue(595 nm) the red form is converted to blue form upon binding of the dye to the
auxochrome group -N[H.sub.2].
The poor nuclear/ cytoplasmic differentiation seen in the use of unmordified Roselle extract and eosin as compared to haematoxylin and eosin may highlight the need for an
auxochrome which stabilizes a staining reaction as obtained in the haematoxylineosin method.
The former band is characteristic of indigo and the latter is ascribed to
auxochromes (N, S[O.sub.3]) joined to the benzene ring.
This likely indicates that COD removal was not affected by the formation of the hydroperoxyl anion (H[O.sub.2.sup.-]) or maybe the dye oxidation by the hydroxyl radicals was not taking place initially in the chromophore, which is responsible for the observed color, but in the
auxochromes. Therefore, further experiments to determine the oxidation pathways should be required.
