How does the Dragendorff reagent work for detecting alkaloids?

Dragondorff’s reagent (potassium iodide-bismuth nitrate) is widely used reagent to detect alkaloids. The heavy metal atom (BiI4) combines with the nitrogen in the alkaloid to form ion pairs. This ion pair forms insoluble orange red colored complex.

How does the Wagner reagent work for detecting alkaloids?

In Wagner reagent preparation, iodine reacts with I- ion from potassium iodide producing I3- ion (brownish solution). In the Wagner test, the metal ion of K+ will bind as covalent coordinate bonding with nitrogen to alkaloid producing a complex precipitate of potassium-alkaloid. The reaction is predicted as Figure 2.

What is Mayers test?

A general presumptive test for cocaine, morphine, heroin, and other alkaloids. Mayer’s reagent is a solution of potassium mercury iodide in water. A positive result is indicated by a cream precipitate.

Which reagent is used to detect alkaloids?

Dragendorff’s reagent is a color reagent to detect alkaloids in a test sample or as a stain for chromatography plates. Alkaloids, if present in the solution of sample, will react with Dragendorff’s reagent and produce an orange or orange-red precipitate.

What is Dragendorff reagent?

DR is a solution of potassium bismuth iodide composing of basic bismuth nitrate (Bi(NO₃)₃), tartaric acid, and potassium iodide (KI), and when contact with alkaloids DR produces an orange or orange red precipitate.

What is the purpose of Alkaloidal reagents?

Alkaloids are useful as diet ingredients, supplements, and pharmaceuticals, in medicine and in other applications in human life. Alkaloids are also important compounds in organic synthesis for searching new semisynthetic and synthetic compounds with possibly better biological activity than parent compounds.

How do you do the Mayers test?

Mayer’s reagent is freshly prepared by dissolving a mixture of mercuric chloride (1.36 g) and of potassium iodide (5.00 g) in water (100.0 ml). Most alkaloids are precipitated from neutral or slightly acidic solution by Mayer’s reagent (potassiomercuric iodide solution) to give a cream coloured precipitate.

What is Wagner’s reagent used for?

An aqueous solution of iodine and potassium iodide; used for microchemical analysis of alkaloids.

How is Mayers reagent prepared?

Dissolve mercuric chloride (2.72 g) in distilled water 020 ml). Separately dissolve potassium iodide 00 g) in distilled water (40 mI). Mix the two solutions and make up to volume (200 ml) with distilled water.

Which Colour is produced in Mayer’s test for alkaloids?

Tests for alkaloids Few drops of Mayer’s reagent were added to 1 mL of extract. A yellowish or white precipitate was formed, indicating the presence of alkaloids.

How do you detect alkaloids?

Chemical Tests for the Detection of Alkaloids:

  1. Mayer’s test: ADVERTISEMENTS: To about 3 ml.
  2. Dragendorff’s test: ADVERTISEMENTS: To about 3 ml of extract, a few drops of Dragendorff’s reagent are added.
  3. Wagner’s test: To about 3 ml of sample solution, a few drops of Wagner’s reagent are added.
  4. Marme’s test:

What is Hager’s reagent?

Hager’s reagent is saturated solution of picric acid [12]. Estimation of total alkaloid content. The total alkaloid content was estimated by bromocresol green (BCG) spectrophotometry method [13,14].