Congo red - Wikipedia
WEBDue to a color change from blue to red at pH 3.0–5.2, Congo red can be used as a pH indicator. Since this color change is an approximate inverse of that of litmus, it can be used with litmus paper in a simple parlor trick: add a drop or two of Congo red to both an acid solution and a base solution.
Congo red - American Chemical Society
WEBSep 8, 2014 · “Congo red” is not the name of a famous African explorer, but a dye that dates to 1883. It was synthesized by P. Böttiger as a textile dye, but it subsequently became more important as a pH indicator. It colors aqueous solutions blue below pH 3.0 and becomes red above pH 5.0.
WEBCongo Red is an acid-base indicator dye. In free solution the colour and absorption characteristics of Congo Red depend not only on the pH but are also governed by the nature of the solvent environment. In tissue sections stained by Congo Red, alteration of the pH and the use of
Adsorption of an anionic dye (Congo red) from aqueous ... - Nature
WEBNov 11, 2019 · Congo red (CR) is a benzidine-based anionic diazo dye that can cause allergic reactions and can be metabolized to benzidine, a carcinogenic product 19. Depending on pH, various molecular...
Congo Red and amyloids: history and relationship - PMC
WEBJan 1, 2019 · Staining with Congo Red (CR) is a qualitative method used for the identification of amyloids in vitro and in tissue sections. However, the drawbacks and artefacts obtained when using this dye can be found both in vitro and in vivo.
Congo Red - an overview | ScienceDirect Topics
WEBCongo red is a reactive agent that changes color from red to dark blue in acidic environments where the pH is less than 3. Acid producing mucosa turns blue within a few minutes, whereas non–acid-producing mucosa remains red.
Differential Congo red staining: the effects of pH, non-aqueous ...
WEBIn tissue sections stained by Congo red, alteration of the pH and the use of non-aqueous solvents can effect differential colouring of the tissue components. Stained sections of unmodified and chemically substituted celluloses show that differential red or blue coloration reflects the acidic or basic character of the substrate.
WEBThe Congo red stain has undergone several modifications since it was first used by Bennhold1 in 1922 in order to increase the specificity for staining amyloid. Most of the laboratories in the United States use the method of Puchtler16 which uses alkaline Congo red …
Congo Red Stain - SpringerLink
WEBJan 9, 2022 · Dense collagen fibers and various other formalin-fixed tissues can be stained, but by using an alcoholic method, combined with high ion strength and high pH (Puchtler method, 1962), the specificity of Congo red staining for amyloid can also be increased.
Congo red - wikidoc
WEBTemplate:PH indicator template Due to a color change from blue to red at pH 3.0-5.2, congo red can be used as a pH indicator. Since this color change is an approximate inverse of that of litmus, it can be used with litmus paper in a simple parlor trick: add a drop or two of congo red to both an acid solution and a base solution.