Ammonium chloride [12125-02-9].
» Ammonium Chloride contains not less than 99.5 percent and not more than 100.5 percent of NH4Cl, calculated on the dried basis.
Packaging and storage Preserve in tight containers.
pH 791: between 4.6 and 6.0, in a solution (1 in 20).
Loss on drying 731 Dry it over silica gel for 4 hours: it loses not more than 0.5% of its weight.
Residue on ignition 281 Add 1 mL of sulfuric acid to about 2 g, accurately weighed, and heat the mixture gently until volatilization is complete: the residue is white, and when ignited, not more than 0.1% of nonvolatile substance remains.
Limit of thiocyanate Acidify 10 mL of a solution (1 in 10) with hydrochloric acid, and add a few drops of ferric chloride TS: no orange-red color is produced.
Heavy metals, Method I 231: 0.001%.
Assay Transfer about 100 mg of Ammonium Chloride, accurately weighed, to a conical flask, add 10 mL of water, and swirl to dissolve. Add 10 mL of glacial acetic acid, 75 mL of methanol, and 0.5 mL of eosin Y TS. Titrate, with shaking, with 0.1 N silver nitrate VS to a pink endpoint. Each mL of 0.1 N silver nitrate is equivalent to 5.349 mg of NH4Cl.
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USP32NF27 Page 1533Pharmacopeial Forum: Volume No. 29(5) Page 1415