Page 17 - Phytochemistry 2 (06-PG 605)

 Separation of a mixture of 4ry and N-Oxide alks:
• The mixture is dissolved in H2O (both are dissolved).
• Precipitation of 4ry alk. by addition of ammonium reineckate, then filter

Qualitative tests for alkaloids:

Alkaloids precipitation reagents:
1. Mayer’s reagent (potassium-mercuric iodide solution).
2. Wagner's reagent (solution of iodine potassium iodide), that gives a reddish
brown precipitate.
3. Hager's reagent (a saturated solution of picric acid), that gives a yellow
precipitate.
4. Dragendorff's reagent (solution of potassium bismuth iodide), that gives an
orange to reddish brown precipitate.

Alkaloids Colour reagents
1- Mandalin's reagent: (sulphovanadic acid) Ammonium vanadate in conc. H2SO4.
2- Froehd's reagent: (sulphomolybdic acid) Molybdic acid or sodium molybdate in
conc. H2SO4. The reagent should be freshly prepared before use.

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