How do you prepare DNP stain?
Dissolve 12g of 2,4-dinitrophenylhydrazine, 60mL of conc. sulfuric acid, and 80mL of water in 200mL of 95% ethanol. Very good general stain, giving a range of colors for different spots. Prepare a solution of 15g vanillin in 250mL ethanol and 2.5mL conc.
What is the purpose of the phosphomolybdic acid PMA stain?
Phosphomolybdic is used as a stain for developing thin-layer chromatography plates, staining phenolics, hydrocarbon waxes, alkaloids, and steroids. Conjugated unsaturated compounds reduce PMA to molybdenum blue.
How do you make anisaldehyde solution?
Preparation Instructions The spray reagent is prepared by adding 0.5 ml of p-anisaldehyde to 100 ml of the Acid Alcohol. Note: Smaller volumes of the spray reagent may be prepared as needed. To prepare 5 ml of the spray reagent, add 25 µl of p-anisaldehyde to 5 ml of the Acid Alcohol.
What does p-anisaldehyde stain?
The p-anisaldehyde and vanillin stains are general purpose, and work for many strong and weak nucleophiles (alcohols, amines), and for many aldehydes and ketones. They do not work on alkenes, aromatics, esters, or carboxylic acids.
How does Anisaldehyde stain work?
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. Cyclopentenyl cations have been postulated as intermediates which condense with anisaldehyde to yield colored compounds.
Which stain used in chromatography?
Stains for TLC Plates
| Name | Visualization of… | Conversion / Selectivity (%) |
|---|---|---|
| Vanillin | Universal stain Very effective for same polarity products (Rf) | Prepare stain as follows 15 g of vanillin 250 mL of 95% ethanol 2.5 mL of conc. sulfuric acid |
How does Cam stain work?
it’s oxidative staining stain and it’s work on the principle of oxidation reduction and it’s work similar to PMA (Phosphomolybdic acid) stain. Upon exposure to reducing organics Mo5+ and Mo4+ compounds are formed which are green or blue colored.
Why iodine is used in TLC?
The iodine staining technique allows us to carry around a marked version of our TLC run rather than having to pencil sketch our spots in the UV viewer. The iodine vapors chemically attach to analytes on the TLC plate.
How do you calculate RF?
The Rf value of a compound is equal to the distance traveled by the compound divided by the distance traveled by the solvent front (both measured from the origin).
What are two common methods of visualizing the spots of molecules on TLC plates?
Visualizing the plate: There are two common methods available for visualizing the spots on the tlc plate. If the compounds under study contain a chromophore (ie an aromatic compound), the plate may be placed under an ultraviolet lamp. The spots will show as dark circles on a fluorescent background.
Which stain is used for chromatography?
Ultraviolet: Look at the plate under the light first when working with compounds with conjugated double bond systems. Iodine: Shake with powdered I2. You can then heat the plate to remove the iodine stain, and use a liquid TLC stain as usual.
How is iodine used as a biological stain?
Used as a mordant in Gram’s staining, iodine enhances the entrance of the dye through the pores present in the cell wall/membrane. Lugol’s solution or Lugol’s iodine (IKI) is a brown solution that turns black in the presence of starches and can be used as a cell stain, making the cell nuclei more visible.
What kind of stain to use with phosphomolybdic acid?
% phosphomolybdic acid in ethanol. More PMA can be used however as stains go PMA is relatively expensive. TLCs developed with PMA stain upon heating give green/dark green/dark blue spots on a yellow/green background (see picture).
What kind of stain is dodeca molybdophosphoric acid?
It is also known as dodeca molybdophosphoric acid or PMA, is a yellow-green chemical compound that is freely soluble in water and polar organic solvents such as ethanol. It is used as a stain in histology and in organic synthesis. Phosphomolybdic acid is a component of Masson’s trichrome stain.
How is phosphomolybdic acid used in chromatography?
Phosphomolybdic is used as a stain for developing thin-layer chromatography plates, staining phenolics, hydrocarbon waxes, alkaloids, and steroids.
Which is the best stain for TLC stains?
A3.1 GENERAL STAINS Phosphomolybdic Acid (PMA): Dissolve 10 g of phosphomolybdic acid in 100 mL of absolute ethanol. Potassium Permanganate: Dissolve 1.5 g of KMnO4, 10 g of K2CO3, and 1.25 mL of 10% NaOH in 200 mL of water. Vanillin: Dissolve 15 g of vanillin in 250 mL of ethanol and add 2.5 mL of conc. sulfuric acid.
