Chemical Test for Alkaloids (Include General & Specific Test) + MCQ (10)
General Chemical Test For Alkaloids :-
i. Mayer’s reagent test (K+ mercuric iodide solution) →Cream colored ppt
ii. Dragendroff’s reagent (K+ bismuth iodide solution)→ Red brown ppt
iii. Wagner’s reagent (iodine K+ iodide solution )→ Red brown ppt
iv. Hager’s reagent (Picric acid)→ Yellow colored ppt
v. Picrolonic acid →Yellow colored ppt
Specific Test For Specific Drug :-
1. Colchicum :- Colchicine + 70%H2SO4 → Yellow colour
Colchicine + Alc. FeCl3 → Red Colour
2. Ergot :-
Drug + Vanurks reagents ( P- dimethyl amino benzaldehyde ) → Blue Colour
3. Nux Vomica :-
Brucine + Conc. HNO3 → yellow to orange colour (Outer part of endosperm)
Ammonium Vanadate + H2SO4 → Purple Colour
4. Opium :-
1. Opium extract + FeCl3→ Reddish purple color (Due to presence of meconic acid )
2. Morphine + HNO3 →Orange red color while codeine donot respond
3. Morphine + K3 Fe (CN6) →Bluish green while codeine do not respond
4. Papaverine + HCl + K3 Fe (CN6) →lemon yellow color
5. Vitali Morrin Test :- For all tropane alkaloids drugs
acetone solution of tropane alkaloids + fuming HNO3 + methanolic KOH → Violet Colour
6. Thaleoquin Test:-
Drug + Br2 water + dil. NH3 → solutions give emerald green colour.
Positive for quinine and quindine. Negative For Cinchona and Cinchonidine.
7. Special Test For Cocaine :- Cocaine + H2SO4 → Characteristics smell of methyl benzoate
8. Ephedra :-
Ephedrine + Ninhydrin Solutions → Violet Colour Drug Extract + Solvent Ether → organic layer (Purple) and aqueous layer (Blue)
9. Xanthine Alkaloids :- Murexide Test :- Caffeine + HCl + KClO3 → Purple Colour
10. Imidazole Alkaloids :- Pilocarpine give 2 specific test.
- Helch’s colour tests :- Blue Colour with K2Cr2O7 + H2O2 + CHCl3
- Ekkert’s colour :- Red colour with Nitroprusside + NaOH
MCQ.
1. Which of the following is dragendroff’s reagent ?
A. KI in dilute iodine solution.
B. Saturated solution of picric acid
C. KI + Bismuth nitrate
D. Potassium mercuric iodide
2. In alkaloids general chemical test of wagner, which colour it is produced ?
A. Red
B. Brown
C. Yellow
D. Cream
3. Which of the following is chemical name of vanurk’s reagent ?
A. P- diethyl amino benzaldehyde
B. P- dimethyl ammide benzaldehyde
C. Citric acid
D. P- dimethyl amino benzaldehyde
4. Which of the following is specific test for xanthine Alkaloids ?
A. Vitali Morrin Test
B. Murexide Test
C. Thaleoquin Test
D. Helchs Test
5. If given drug sample is give positive result of thaleoquin test which chemical constituents is present ?
A. Cinchonine
B. Quinine
C. A and B
D. None of the above
6. Vitali Morrin Test is specific For
A. Tropan alkaloid
B. Quinoline alkaloid
C. Xanthine alkaloid
D. Amino alkaloid
7. Opium extract give red colour with fecl3 due to presence of
A. Papaverine
B. Cocaine
C. Meconic acid
D. Morphine
8. Colchicine + 70% H2SO4 =
A. Yellow colour
B. Red colour
C. Green colour
D. Violet colour
9. Which of the following is specific test for pilocarpine ?
A. Vitali Morrin Test
B. Helchs Test
C. A and B
D. None of the above
10. Which of the following is reagent of thaleoquin test ?
A.Drug + Br2 water + Dil. HNO3 solution
B.Drug + Br2 water + Dil. H2SO4 solution
C.Drug + Cl water + Dil. NH3 solution
D. Drug + Br2 water + Dil. NH3 solution
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Answer Key :-
1. C
2. B
3. D
4. B
5. B
6. A
7. C
8. A
9. B
10. D
Reference :- 16 Edition of Trease and Evans Pharmacognosy Text Book ( Pg. No. :-353 to 413 )