ISOLATION OF ALKALOIDS by bharath.

 Isolation of alkaloids is very easy.
 First we have to identify the presence of alkaloid in the plant.
 These alkaloids are treated with the different reagents like
tannic acid,
picric acid,
picolinic acid,
perchloric acid,
mercuric iodide{Mayer’s reagent},
iodine dissolved in potassium iodide{Wegner’s reagent},
potassium bismuth iodide{Dragendoffr’s reagent},
phosphomolybdic acid{Sonneuschein’s reagent }, and
phosphotungstic acid {Scheibler’s reagent}, with wich the alkaloids either give precipitate or turbidity.
 These reagents do not have quantitative analysis of alkaloids, because the compound are not sufficiently insoluble and partly because the reagents precipitate out other organic substances also. A general procedure recommended by Manske is described below.


 Extraction of plant material with petroleum ether for the removal of soluble fats
 Again extraction with methyl alcohol to remove cellulosic and other insoluble material and the filtrate so obtained is evaporated.
 Then it is dissolved in water, acidified to pH 2 and steam distilled to remove methyl alcohol.
 Now paraffin is used to remove suspended impurities.
 Then filtrate is extracted with ether or chloroform to remove water soluble non basic organic material and the steam distilled where the steam volatile alkaloids are separated.
 Again extracted with ether or chloroform and the etheral layer obtained after this extraction is evaporated to give crude alkaloids.
 The crude mixture is separated into individual alkaloids by
 Fractional crystallization,
 Fractional precipitation,
 Column chromatography,
 Partition chromatography,
 Gas chromatography ,
 Counter current extraction.
This is about isolation of alkaloids