Ammonium Carbonate

Carbonic acid, monoammonium salt, mixt. with ammonium carbamate.
Monoammonium carbonate mixture with ammonium carbamate [8000-73-5].
» Ammonium Carbonate consists of ammonium bicarbonate (NH4HCO3) and ammonium carbamate (NH2COONH4) in varying proportions. It yields not less than 30.0 percent and not more than 34.0 percent of NH3.
Packaging and storage— Preserve in tight, light-resistant containers, at a temperature not above 30.
Identification— When heated, it is volatilized without charring, and the vapor is alkaline to moistened litmus paper. A solution (1 in 20) effervesces with acids.
Residue on ignition 281: not more than 0.1%.
Chloride 221 A 2.0-g portion shows no more chloride than corresponds to 0.10 mL of 0.020 N hydrochloric acid (0.0035%).
Sulfate 221 A 2.0-g portion shows no more sulfate than corresponds to 0.10 mL of 0.020 N sulfuric acid (0.005%).
Heavy metals, Method I 231 Reduce to a coarse powder and volatilize 2 g of it on a steam bath. Add to the residue 1 mL of 3 N hydrochloric acid, and evaporate to dryness. Dissolve the residue in 2 mL of 1 N acetic acid, and add water to make 25 mL: the limit is 0.001%.
Assay— Place in a weighing bottle about 10 mL of water, tare the bottle and its contents, add about 2 g of Ammonium Carbonate, and weigh accurately. Transfer the contents of the bottle to a 250-mL flask, add 50.0 mL of 1 N sulfuric acid VS, and, when solution has been effected, add methyl orange TS, and titrate the excess acid with 1 N sodium hydroxide VS. Perform a blank determination (see Residual Titrations under Titrimetry 541). Each mL of 1 N sulfuric acid is equivalent to 17.03 mg of NH3.
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Monograph Robert H. Lafaver, B.A.
(EM105) Excipient Monographs 1
USP32–NF27 Page 1165