SODIUM BENZOATE
Prepared at the 46th JECFA (1996), published in FNP 52 Add 4 (1996)
superseding specifications prepared at the 17th JECFA (1974), published
in FNP 4 (1978) and in FNP 52 (1992). Metals and arsenic specifications
revised at the 63rd JECFA (2004). A group ADI of 0-5 mg/kg bw for
benzoic acid and salts was established at the 27th JECFA (1983), and
maintained at the 57th JECFA (2001)
SYNONYMS INS No. 211
DEFINITION
Chemical names Sodium benzoate, sodium salt of benzenecarboxylic acid, sodium salt of
phenylcarboxylic acid
C.A.S. number 532-32-1
Chemical formula C7H5NaO2
Structural formula
Formula weight 144.11
Assay Not less than 99.0% on the dried basis
DESCRIPTION White, almost odourless, crystalline powder, flakes or granules
FUNCTIONAL USES Antimicrobial preservative
CHARACTERISTICS
IDENTIFICATION
Solubility (Vol. 4)
Freely soluble in water, sparingly soluble in ethanol
Test for benzoate (Vol. 4)
Passes test
Use a 10% solution of the sample
Test for sodium (Vol. 4)
Passes test
PURITY
Loss on drying (Vol. 4)
Not more than 1.5% (105o, 4 h)
Acidity or alkalinity Dissolve 2 g of the sample, weighed to the nearest mg, in 20 ml of freshly
boiled water. Not more than 0.5 ml of either 0.1N sodium hydroxide or
0.1N hydrochloric acid should be required for neutralization, using
phenolphthalein TS as indicator.
Readily carbonizable
substances
Dissolve 0.5 g of the sample, weighed to the nearest mg, in 5 ml of
sulfuric acid TS. The colour produced should not be darker than a light
pink ("Matching Fluid Q")
Chlorinated organic
compounds (Vol. 4)
Not more than 0.07% (as chlorine)
Test 0.25 g of the sample using 0.5 ml of 0.01N hydrochloric acid in the
control
Readily oxidizable
substances
Add 1.5 ml of sulfuric acid to 100 ml of water, heat to boiling and add
0.1N potassium permanganate, dropwise, until the pink colour persists for
30 sec. Dissolve 1 g of the sample, weighed to the nearest mg, in the
heated solution, and titrate with 0.1N potassium permanganate to a pink
colour that persists for 15 sec. Not more than 0.5 ml should be required.
Lead (Vol. 4)
Not more than 2 mg/kg
Determine using an atomic absorption technique appropriate to the
specified level. The selection of sample size and method of sample
preparation may be based on the principles of the method described in
Volume 4, “Instrumental Methods.”
METHOD OF
ASSAY
Weigh, to the nearest mg, 3 g of the sample previously dried for 4 h at
105o and transfer to a 250-ml Erlenmeyer flask. Add 50 ml of water to
dissolve the sample. Neutralize the solution, if necessary, with 0.1N
hydrochloric acid, using phenolphthalein TS as indicator. Add 50 ml of
ether and a few drops of bromophenol blue TS, and titrate with 0.5N
hydrochloric acid, shaking the flask constantly, until the colour of the
indicator begins to change. Transfer the lower aqueous layer to another
flask. Wash the ethereal layer with 10 ml of water, and add the washing
and an additional 20 ml of ether to the separated aqueous layer.
Complete the titration with the 0.5N hydrochloric acid, shaking constantly
the flask.
Each ml of 0.5N hydrochloric acid is equivalent to 72.05 mg of C7H5NaO2.
SODIUM BENZOATE
SYNONYMS
DEFINITION
Chemical names
C.A.S. number
Chemical formula
Structural formula
Formula weight
Assay
DESCRIPTION
FUNCTIONAL USES
CHARACTERISTICS
IDENTIFICATION
PURITY
Acidity or alkalinity
Readily carbonizable substances
Readily oxidizable substances
METHOD OF
ASSAY