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

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