Schiff test

Abstract: Schiff reagent may be made by simply adding 1 g. fuchsin, 1.9 g. sodium metabisulfite to 100 ml. 0.15 N hydrochloric acid, shaking at intervals or mechanically for 2 hours, decolorizing with charcoal and filtering.To obtain perfectly colorless Schiff reagent, it is necessary that fresh activated charcoal be used. If the final product is not water white, a fresh sample of activated charcoal should be obtained, and the product retreated and refiltered.Schiff reagent precipitates a white crystalline substance after varying periods of cold storage, apparently a polymer which can be partly depolymerized by boiling and reconstituted into a Schiff reagent. The reconstituted reagent rather promptly precipitates again. Hence reconstitution is impractical and preparation of fresh batches at intervals of 2-3 weeks is recommended.

Abstract: On oxidation with performic (or peracetic) acid ceroid becomes Schiff positive. This reaction is prevented by prior bromination, but not by acetylation. Interposition of bisulfite, semi-carbazide or phenylhydrazine blockades after the oxidation and before the leucofuchsin prevents the positive Schiff reaction on short exposure, but a long (3 hour) Schiff bath overcomes the blockade in all three instances. Prior acetylation blocks the periodic acid Schiff reaction of ceroid, but bromination does not.These findings indicate the presence in ceroid of ethylenic groupings as well as 1,2 glycols.

Abstract: A comparison is made of the relative affinities of aldehyde-fuchsin and the Schiff reagent for various tissue elements in different states of oxidation.Glycogen, gastric mucus, kidney brush border, intestinal striated border, reticular tissue, gastric parietal cell canaliculi, and Paneth cell granules react with neither aldehyde-fuchsin nor the Schiff reagent without periodic acid or stronger oxidation.Beta cell granules of the islets of Langerhans, keratin, mast cells, elastic fibers, hyaline cartilage, goblet cells, thyroid colloid, argentaffine cell granules, and the acrosomes of spermatozoa are stained by aldehyde-fuchsin without oxidation. None of these tissue elements exhibit a clearly positive reaction with the Schiff reagent under similar conditions. However, elastic fibers, hyaline cartilage, and acrosomes do display a slight coloration.Since the tissue elements which do not stain with aldehyde-fuchsin without previous oxidation act in a similar manner toward both aldehyde-fuchsin and the Schiff ...

Abstract: In order to obtain a better understanding of the “periodic-acid-Schiff” reaction, also known as the “periodic-acid fuchsin-sulfurous-acid” reaction, three types of investigations were carried out1) The Schiff reagent was replaced by other aldehyde reagents: benzidine or o-dianisidine. There was no significant change in the histological distribution and intensity of the reactions occurring after periodic acid oxidation.2) Periodic acid was replaced by another oxidizing agent: lead tetraacetate (dissolved in acetic acid). There was no significant change in the histological distribution of the reactions with the Schiff reagent, but some change in their intensity. It was concluded that 1,2-glycols and a-amino alcohols play the main role in the reactions with both oxidants. The presence of α-hydroxy acids in some types of mucous cells is suggested by the results with lead tetraacetate.Incidently, glycogen and starch are not sufficiently oxidized by lead tetraacetate (in acetic acid) at room temperature to give...