Identification Tests for Tannin - Pharmacognosy B Pharmacy 5th semesters

 Identification Test for Tannin

You may also read Introduction to Tannins

1. Goldbeater's skin test: 

• Goldbeater's Skin soaked in 2% HCl for 5 minutes.
• Rinse with distilled water
• Place in solution of tannin for 5minutes
• Wash distilled water
• Treat with Ferrous sulphate solution
• Black-Brown Colour observed.

2. Gelatine Test:

• Tannin Solution + 1% Gelatine Solution + 10% NaCl Solution
• Gives White Buff Colour precipitate.

3. Ferric chloride test:

• Tannin extract + Ferric Chloride Solution
• Gives
• Blue colour: Hydrolysable tannin
• Brownish green colour: Condensed tannin

4. Phenazone Test:

• Aqueous extract of drug + Sodium Hydrogen Phosphate, Heated together
• Cooled and filtered.
• Filtrate + Phenazone solution
• Gives Bulky coloured precipitate.

5. Chlorogenic acid test:

• Drug extract + Aqueous ammonia
• Gives Green colour

6. Vanillin HCl acid test:

• Sample solution + vanillin HCl reagent(Vanillin 1g + Alcohol + 10ml conc. HCl)
• Gives Pink or Red Colour(Phloroglucinol formation)

7. Match stick test(Catechin test):

• Match stick dipped in aqueous plant extract
• Dried near the flame
• Moistened with conc. HCl
• Warm near flame
• Match stick wood turns Pink-Red colour(Phloroglucinol formation)

You may also read Introduction to Tannins