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Testing Procedure (Method of analysis) for Aluminium Salts, Amines and Ammonium Salts


Learn how to test the Aluminium Salts, Amines and Ammonium Salts in Pharmaceutical preparations.

Aluminium Salts

A. Dissolve about 20 mg of the substance under examination in 2 ml of water or use 2 ml of the prescribed solution, add about 0.5 ml of 2 M hydrochloric acid and about 0.5 ml of thioacetamide reagent; no precipitate is produced. Add drop wise 2M sodium hydroxide; a gelatinous white precipitate is produced which re-dissolves on addition of further 2M sodium hydroxide. Gradually add ammonium chloride solution; the gelatinous white precipitate appears.
B. Dissolve about 20 mg of the substance under examination in 5 ml of water or use 5 ml of the prescribed solution, add 5 drops of ammonium acetate solution and 5 drops of a 0.1 per cent w/v solution of mordant blue 3; an intense purple color is produced.
C. To a solution of the substance under examination in water add dilute ammonia solution until a faint precipitate is produced and then add 0.25 ml of a freshly prepared 0.05 per cent w/v solution of quinalizarin in a 1 percent w/v solution of sodium hydroxide. Heat to boiling, cool, and acidify with an excess of acetic acid, a reddish violet color is produced.

Amines, Primary Aromatic

Acidify the prescribed solution with 2 M hydrochloric acid or dissolve 0.1 g of the substance under examination in 2 ml of 0.1M hydrochloric acid and add 0.2 ml of sodium nitrite. After 1 or 2 minutes add the solution to 1ml of 1-naphthol solution; an intense orange or red color and, usually, a precipitate of the same color is produced.


Ammonium salts

A. Heat a few mg of the substance under examination with sodium hydroxide solution; ammonia is evolved, which is recognisable by its odor and by its action on moist red litmus paper, which turns blue.
B. To the prescribed solution add 0.2 g of light magnesium oxide. Pass a current of air through the mixture and direct the gas that is evolved to just beneath the surface of a mixture of 1 ml of 0.1 M hydrochloric acid and 0.05 ml of methyl red solution; the color of the solution changes to yellow. On addition of 1ml of a freshly prepared 10 per cent w/v solution of sodium cobaltinitrite, a yellow precipitate is produced.
Ankur Choudhary is India's first professional pharmaceutical blogger, author and founder of Pharmaceutical Guidelines, a widely-read pharmaceutical blog since 2008. Sign-up for the free email updates for your daily dose of pharmaceutical tips.
Email: .moc.enilediugamrahp@ofni Need Help: Ask Question


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