Chemical Properties
dark green powder
Uses
Neutral Red is used as indicator for nitrogen determination; pH indicator.
Application
Transition of pH Indicator: pH 6.8 - 8.0, red to yellow. Basic red 5 is a dye used in histology for staining nuclei. It is also a pH indicator. As such it is used in microbial culture media for differentation of bacteria. For example MacConkey agar contains it and lactose. Acidification by lactic acid turns on the Basic red 5. Therefore, colonies formed by bacteria that ferment lactose into lactic acid will turn red and stand out from the pale colonies of non-lactose-fermenting bacteria. Basic red 5 is also used in cell viability tests based on the ability to incorporate and bind it.
Definition
ChEBI: A hydrochloride obtained by combining the free base of neutral red with one equivalent of hydrochloric acid. Neutral red acts as a pH indicator, changing from red to yellow between pH 6.8 and 8.0.
Preparation
(a) N,N-dimethyl-4-nitrosobenzenamine?and 4-Methylbenzene-1,3-diamine???reaction, form Toluylene Blue (Basic Dye, C.I. 49410), heating make cyclization; (b) oxidation N1,N1-dimethylbenzene-1,4-diamine?, and 4-Methylbenzene-1,3-diamine mixture.
General Description
Neutral red (C.I. 50040) is a protonated diaminophenazine dye. It is aminodimethylaminomethylphenazinehydrochloride, C15H17N4Cl.
Biochem/physiol Actions
Neutral red is a widely used cationic fluorochrome that is known to accumulate in the Golgi complex and nuclei after first staining lysosomes.
Biotechnological Applications
Neutral Red is a non-toxic stain used for studies of living cells, for example to observe plasmolysis. The stain is used as an aqueous solution (0.1 %, w/v) and stains lipids in vacuoles and certain cell walls.
Staining Procedures
Neutral Red is a non-toxic stain used for studies of living cells, for example to observe plasmolysis. The stain is used as an aqueous solution (0.1 %, w/v) and stains lipids in vacuoles and certain cell walls.
Properties and Applications
red light purple and red. Soluble in water is cherry red, soluble in ethanol for product red colour with red fluorescent light brown. The strong sulfuric acid for green, blue for diluted, and then into a product red. The dye solution to join strong sodium hydroxide solution have yellow brown precipitation.
Purification Methods
In aqueous solution it is red at pH 6.8 and yellow at pH 8.0. [Beilstein 25 III/IV 3054.]
