Isolation absorption/adsorption

As an example, five different synthetic colorants (Tartrazine, Sunset Yellow, Ponceau 4R, Amaranth, and Brilliant Blue FCF) from drinks and candies were separated on a polyamide adsorbent at pH 4, eluted with an alkaline-ammonia solution. By another method, 13 synthetic food colorants were isolated from various foods using specific adsorption on wool. After elution with 10% ammonia solution and gentle warming, an absorption spectrum of the resulting colorant solution was recorded, compared to the reference spectra of pure colorants, and identified by linear regression analysis. ... 

Inorganic compound adsorptions, particularly those that are colored, involve the promotion of electrons in the d orbitals. Absorption can occur in both isolated compounds and inorganic moieties with organic ligands. 

The interfacial aqueous coordination chemistry of natural particles, in particular their surface complexation reactions, owes much of its development to the research of Werner Stumm. Beginning with the tentative interpretation of specific adsorption processes in terms of chemical reactions to form inner-sphere surface complexes, his seminal questions spawned a generation of research on the detection and quantitation of these surface species. The application of noninvasive spectroscopy in this research is exemplified by electron spin resonance and extended X-ray absorption fine structure studies. These studies, in turn, indicate the existence of a rich variety of surface species that transcend the isolated surface complex in both structure and reactivity, thereby stimulating future research in molecular conceptualizations of the particle-water interface. 

Fractionation of aquatic humic substances by adsorptive interactions has been the most successful method for fractionation as well as concentration and isolation. Humic solutes readily interact with various adsorptive surfaces without the requirement of crossing the interface surface as is necessary with solvent partitioning or absorptive interactions. 

Finally, adsorption controls can only be performed with purified antigens. In cases of isolated proteins, it is difficult to get a purified antigen clean enough to use as the antigen for an absorption control. For antibodies made from small synthesized peptides, it is possible to get pure antigen and these are the best absorption controls. 

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