Acetic Acid

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition

Issued and maintained by the United States Pharmacopeial Convention (USP)

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Acetic acid;

Acetic acid

CAS RN®: 64-19-7.

1 DEFINITION

Acetic Acid is a solution containing NLT 36.0% and NMT 37.0%, by weight, of C₂H₄O₂

2 IDENTIFICATION

2.1 A. IDENTIFICATION TESTS GENERAL, Acetate (191):

Meets the requirements

3 ASSAY

3.1 PROCEDURE

Analysis: Place 6 ml. in a tared, glass-stoppered flask, and weigh. Add 40 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: 36.0%-37.0%

4 IMPURITIES

4.1 NONVOLATILE RESIDUE

Analysis: Evaporate 20 mL in a tared porcelain dish on a steam bath, and dry at 105° for 1 h.

Acceptance criteria: The weight of the residue does not exceed 1.0 mg (0.005%).

4.2 CHLORIDE

Sample solution: Acetic acid (1 in 10) in water

Analysis: To 10 mL of the Sample solution add 5 drops of silver nitrate TS.

Acceptance criteria: No opalescence is produced.

4.3 SULFATE

Sample solution: Acetic acid (1 in 10) in water

Analysis: To 10 mL of the Sample solution add 5 drops of barium chloride TS.

Acceptance criteria: No turbidity is produced.

4.4 READILY OXIDIZABLE SUBSTANCES

Analysis: Dilute 4.0 mL in a glass-stoppered vessel with 20 mL of water, and add 0.30 mL of 0.10 N potassium permanganate.

Acceptance criteria: The pink color is not changed to brown at once, and the liquid does not become entirely brown or free from a pink tint in less than 30 s.

5 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in tight containers.