Dextrin and salt as impurities of histological dyes

Selective Coloration of Biological Material

“…For example with aqueous solvents hydrophobic bonding will be possible. In keeping with this expectation, coloration by large acid and basic dyes from columbically unfavourable dyebath conditions occurred most strongly from aqueous solutions and with dyes of predominantly hydrophobic character [66]. Increases in entropy of both solvent and dye are possible during such processes as the coloration of liquid droplets of neutral lipids with non-ionic dyes from aqueousalcohol dyebaths.…”

“…Further nondirected dye-tissue attractions are van der Waals forces. Though such a source of affinity has been scoffed at, evidence for the role of these attractions, a t least with large dyes and with particular substrates (such as elastic fibres and eosinophil granules), has been forthcoming [64,65]. In some studies the confusing effects of hydrophobic bonding (see below) have been dissected out by the use of solvents of varied water contents [661.…”

“…Be that as it may, various workers have compared the performance of dyes of differing structures, in various coloration systems. Such studies have led, e.g., to claims for the importance of dye size (for traditional stains for connective tissue [51, for DNA/RNA-rich sites [841, and for mucins I821 1, hydrogen bonding groups (certain elastic fibre stains [1521, and Schiff reagent-substitutes 11 531 ); the size of the aromatic system (for elastic fibre stains (64,1741, and acid and basic dyeing in general [661 1; dye stereochemistry (nucleic acid stains [491 1; and hydrophobic character (for acid and basic dyes [66], and for lipid stains [1751 1. Surprisingly, in view of the vast range of commercially available dyestuffs, studies are commonly limited to the comparison of a few, rather than of many different, dyes.…”

Dyes and other colorants in microtechnique and biomedical research

“…There are staining methods, including some of those for elastin [18,21] and collagen [22,23] that are not impaired by high salt concentrations, indicating that ionic attraction to a specific substrate is not always essential, even though staining fails when strongly basic amino acid side-chains (arginine and lysine) have been chemically blocked [24,25].…”

Biological Stains and Their Uses

“…Information on the presence of particular chemical entities, e.g. neutral lipids, carboxyl groups, Ca (11) ions.…”