Glacial Acetic Acid
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C2H4O2 60.05
Acetic acid     [64-19-7].
Glacial Acetic Acid contains NLT 99.5% and NMT 100.5%, by weight, of C2H4O2.
•  Identification Tests—General, Acetate 191: Meets the requirements
Sample solution (for lanthanum nitrate test):  Glacial Acetic Acid and water (1:100)
•  Procedure
Sample solution:  Measure 2 mL of Glacial Acetic Acid into a glass-stoppered flask, previously tared while containing about 20 mL of water, and weigh again to obtain the weight of the substance under assay.
Analysis:  Add 20 mL of water, then add phenolphthalein TS. Titrate with 1 N sodium hydroxide VS. Each mL of 1 N sodium hydroxide is equivalent to 60.05 mg of C2H4O2.
Acceptance criteria:  99.5%–100.5%
Inorganic Impurities 
•  Limit of Nonvolatile Residue: Evaporate 20 mL in a tared dish, and dry at 105 for 1 h: the weight of the residue does not exceed 1.0 mg.
•  Heavy Metals 231: NMT 5 ppm
Sample solution:  To the residue obtained in the test for Limit of Nonvolatile Residue add 8 mL of 0.1 N hydrochloric acid, warm gently until solution is complete, dilute with water to 100 mL, and use 20 mL.
•  Chloride and Sulfate, Chloride 221
Sample solution:  Dilute 1.0 mL with 20 mL of water.
Analysis:  Add 5 drops of silver nitrate TS.
Acceptance criteria:  No opalescence is produced.
•  Chloride and Sulfate, Sulfate 221
Sample solution:  Dilute 1.0 mL with 10 mL of water.
Analysis:  Add 1 mL of barium chloride TS.
Acceptance criteria:  No turbidity is produced.
Organic Impurities 
•  Procedure: Readily Oxidizable Substances
Sample solution:  Dilute 2.0 mL in a glass-stoppered vessel with 10 mL of water.
Analysis:  Add 0.10 mL of 0.10 N potassium permanganate.
Acceptance criteria:  The pink color is not changed to brown within 2 h.
•  Congealing Temperature 651: NLT 15.6
•  Packaging and Storage: Preserve in tight containers, and store at room temperature.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Feiwen Mao, M.S.
Senior Scientific Liaison
(SM32010) Monographs - Small Molecules 3
USP35–NF30 Page 2065
Pharmacopeial Forum: Volume No. 36(3) Page 645