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