Page 20 - phytochemistry general program

Separation of a mixture of 4ry and N-Oxide alks: .4
The mixture is dissolved in H2O (both are dissolved). .1
Precipitation of 4ry alk. by addition of ammonium reineckate, then filter .2

Qualitative tests for alkaloids:

Alkaloids precipitation reagents:
Mayer’s reagent (potassium-mercuric iodide solution). .1
Wagner's reagent (solution of iodine potassium iodide), that gives a reddish .2

brown precipitate.
Hager's reagent (a saturated solution of picric acid), that gives a yellow .3

precipitate.
Dragendorff's reagent (solution of potassium bismuth iodide), that gives an .4

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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