The alkaloid is obtained from an aqueous extract of tobacco by distillation with slaked lime, the distillate being acidified with oxalic acid, concentrated to a syrup and decomposed by potash.
Cadmium salts can be recognized by the brown incrustation which is formed when they are heated on charcoal in the oxidizing flame of the blowpipe; and also by the yellow precipitate formed when sulphuretted hydrogen is passed though their acidified solutions.
The solution is then acidified, and the phenols are'liberated and form an oily layer on the surface of the acid.
The mixture is then cooled, acidified by means of sulphuric acid, and titrated with decinormal sodium thiosulphate solution.
The solution obtained is neutralized, concentrated on the water-bath, acidified by sulphuric acid and extracted with ether.