(Ammonium Hydrogen Carbonate, Ph Eur monograph 1390)

NH4HCO3  79.1   1066-33-7

Action and use

Expectorant.

Preparations

Aromatic Ammonia Solution

Strong Ammonium Acetate Solution

Aromatic Ammonia Spirit

Ph Eur


DEFINITION

Content

98.0 per cent to 101.0 per cent.

CHARACTERS

Appearance

Fine, white or almost white, crystalline powder or white or almost white crystals, slightly hygroscopic.

Solubility

Freely soluble in water, practically insoluble in ethanol (96 per cent).

It volatilises rapidly at 60 °C. The volatilisation takes place slowly at ambient temperatures if the substance is slightly moist. It is in a state of equilibrium with ammonium carbamate.

IDENTIFICATION

 A. It gives the reaction of carbonates and bicarbonates (2.3.1).

 B. Dissolve 50 mg in 2 mL of water R. The solution gives the reaction of ammonium salts (2.3.1).

TESTS

Solution S

Dissolve 14.0 g in 100 mL of distilled water R. Boil to remove the ammonia, allow to cool and dilute to 100.0 mL with distilled water R.

Chlorides (2.4.4)

Maximum 70 ppm.

Dilute 5 mL of solution S to 15 mL with water R.

Sulfates (2.4.13)

Maximum 70 ppm, determined on solution S.

Iron (2.4.9)

Maximum 40 ppm.

Dilute 1.8 mL of solution S to 10 mL with water R.

Heavy metals (2.4.8)

Maximum 10 ppm.

Dissolve cautiously 2.5 g in 25 mL of 1 M hydrochloric acid . 12 mL of the solution complies with test A. Prepare the reference solution using lead standard solution (1 ppm Pb) R.

ASSAY

Dissolve cautiously 1.0 g in 20.0 mL of 0.5 M sulfuric acid and dilute to 50 mL with water R. Boil, cool and titrate the excess of acid with 1 M sodium hydroxide, using 0.1 mL of methyl red solution R as indicator.

1 mL of 0.5 M sulfuric acid is equivalent to 79.1 mg of NH4HCO3.

STORAGE

In an airtight container.


Ph Eur