Dyes used as spot test reagent for detcting sulphurous acid
Answers
Anisaldehyde - sulfuric acid is a universal reagent for natural products, that makes color differentiation possible. It is a reagent for anitoxidants, steroids, prostaglandins, carbohydrates, phenols, glycosides, sapogenins, essential oil components or terpenes, antibiotics and mycotoxins.
This stain is an excellent multipurpose visualization method for examining TLC plates. It is sensitive to most functional groups, especially those which are strongly and weakly nucleophilic. It tends to be insensitive to alkenes, alkynes, and aromatic compounds unless other functional groups are present in the molecules which are being analyzed.
It tends to stain the TLC plate itself, upon mild heating, to a light pink color, while other functional groups tend to vary with respect to coloration.
Answer:
- The Schiff reagent is the reaction product of a dye formulation such as fuchsin and sodium bisulfite; pararosaniline (which lacks an aromatic methyl group) and new fuchsin (which is uniformly mono-methylated ortho to the dye's amine functionalities) are not dye alternatives with comparable detection chemistry