Understanding the Main Ingredient in Ehrlich Reagent

Ehrlich reagent or Ehrlich’s reagent is actually a colorimetric spot test that is used in identifying indoles. It contains p–dimethylaminobenzaldehyde, which is its main ingredients, allowing it to act as an indicator to determine urobilinogen and indoles.

The p–dimethylaminobenzaldehyde or para–dimethylaminobenzaldehyde (DMAB) is a compound that contains aldehyde and amine, used in Ehrlich regent to test for the indoles. It can also be used to determine hydrazine. Also, the group of carbonyl often reacts with the two-position of indole, but it may respond at the N-1 or C-3 positions as well.

The Role of p–dimethylaminobenzaldehyde in the Reagent

The DMAB is the primary ingredient in ehrlich reagent. It serves as a powerful or strong electrophile that reacts with the α-carbon of indole rings in order to develop an adduct that’s blue in color. It can also be utilized to identify any presence of the indole alkaloids. It is important to note that not ever indole alkaloid gives a colored result adduct due to steric hindrance that doesn’t let the reaction to continue.

Furthermore, Ehrlich reagent is being used as a reagent to identify urobilinogen in colored urine and a stain in thin layer chromatography. When you leave the urine sample in order to oxidize in air to develop urobilin, the Ehrlich reagent won’t identify the urobilinogen. When several drops of the reagent are added to three milliliters of urine in a tube, you will see the color change to red or dark pink. The level or change in the color is relative to the overall urobilinogen amount in the sample urine.

In order to fully understand Ehrlich reagent and its function, it is important to learn more about its ingredients what it contains. Understanding p–dimethylaminobenzaldehyde will help you know more about its composition.

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