Ph Eur
C7H5NaO3 -- 160.1 -- 54-21-7
DEFINITION
Sodium 2-hydroxybenzenecarboxylate.
Content: 99.0 per cent to 101.0 per cent (dried substance).
CHARACTERS
Appearance: White or almost white, crystalline powder or small, colourless crystals or shiny flakes.
Solubility: Freely soluble in water, sparingly soluble in ethanol (96 per cent).
IDENTIFICATION
First identification A, C.
Second identification B, C.
A. Infrared absorption spectrophotometry.
B. Solution S (see Tests) gives the reactions of salicylates.
C. It gives reaction (b) of sodium.
TESTS
Solution S: Dissolve 5.0 g in carbon dioxide-free water prepared from distilled water and dilute to 50 ml with the same solvent.
Appearance of solution: Solution S is clear and not more intensely coloured than reference solution BY6.
Acidity: To 20 ml of solution S add 0.1 ml of phenol red solution. The solution is yellow. Not more than 2.0 ml of 0.01 M sodium hydroxide is required to change the colour of the indicator to violet-red.
Chlorides: Maximum 200 ppm.
Sulphates: Maximum 600 ppm.
Heavy metals: Maximum 20 ppm.
Loss on drying: Maximum 0.5 per cent, determined on 1.00 g by drying in an oven at 105C.
ASSAY
Dissolve 0.130 g in 30 ml of anhydrous acetic acid. Titrate with 0.1 M perchloric acid, determining the end-point potentiometrically.
1 ml of 0.1 M perchloric acid is equivalent to 16.01 mg of C7H5NaO3.
C7H5NaO3 --- 160.10
Benzoic acid, 2-hydroxy-, monosodium salt.
Monosodium salicylate -- [54-21-7].
Sodium Salicylate contains not less than 99.5 percent and not more than 100.5 percent of C7H5NaO3, calculated on the anhydrous basis.
Identification: A solution (1 in 20) responds to the tests for Sodium and for Salicylate.
Water: not more than 0.5%.
Sulfite or thiosulfate: Add 1 mL of hydrochloric acid to a solution of 1.0 g in 20 mL of water, and filter the liquid: not more than 0.15 mL of 0.10 N iodine is required to produce a yellow color in the filtrate.
Heavy metals: Dissolve 2 g in 46 mL of water. Add, with constant stirring, 4 mL of 3 N hydrochloric acid, filter, and use 25 mL of the filtrate: the limit is 0.002%.
Assay: Transfer about 700 mg of Sodium Salicylate, accurately weighed, to a 250-mL beaker. Add 100 mL of glacial acetic acid, stir until the sample is completely dissolved, add crystal violet, and titrate with 0.1 N perchloric acid VS. Perform a blank determination, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 16.01 mg of C7H5NaO3.
