C3H5NaO2
96.1 -- 137-40-6
Action and use
Antifungal
DEFINITION
Sodium propionate
Content
99.0 per cent to 101.0 per cent Sodium propionate (dried substance).
CHARACTERS
Appearance
Colourless crystals or, white or almost white powder, slightly hygroscopic.
Solubility
Freely soluble in water, sparingly soluble in alcohol, practically insoluble in
methylene chloride.
IDENTIFICATION
First identification A, D.
Second identification B, C, D.
A. Infrared
absorption spectrophotometry.
Comparison reference spectrum of sodium
propionate.
B. Dissolve 0.1 g in a mixture of 2 ml of copper sulphate solution and 2
ml of methylene chloride. Shake vigorously and allow to stand. Both the upper and the
lower layer show a blue colour.
C. To 5 ml of solution S add 2 ml of 0.1 M silver
nitrate. A white precipitate is formed.
D. Solution S gives reaction of sodium.
TESTS
Solution S
Dissolve 10 g Sodium propionate in carbon dioxide-free water
prepared from distilled water and dilute to 100 ml with the same solvent.
Appearance of solution
Solution S is clear and colourless.
pH
7.8 to 9.2
Dilute 1 ml of solution S to 5 ml with water.
Related substances
Liquid chromatography.
Test solution: Dissolve 0.250 g of the substance to be
examined in water and dilute to 100 ml with the same solvent.
Reference solution (a)
Dissolve 10 mg of the substance to be examined and 10 mg of sodium acetate in
water and dilute to 100 ml with the same solvent.
Reference solution (b) Dilute 1.0
ml of the test solution to 100 ml with water.
Column: ı
ı— size: l = 0.25 m, Ø =
4.6 mm;
ı— stationary phase: octadecylsilyl silica gel for chromatography
(5μm).
Mobile phase Dilute 1 ml of phosphoric acid R to 1000 ml with water.
Flow
rateı1 ml/min.
Detection Spectrophotometer at 210 nm.
Injectionı20 μl.
System
suitability Reference solution (a):
ı— resolution: minimum 5 between the peaks due to
sodium acetate and sodium propionate.
Limits:
ı— any impurity: not more than 0.1 times the area of the principal
peak in the chromatogram obtained with reference solution (b) (0.1 per cent);
ı—
total: not more than half the area of the principal peak in the chromatogram obtained
with reference solution (b) (0.5 per cent);
ı— disregard limit: 0.05 times the area
of the principal peak in the chromatogram obtained with reference solution (b) (0.05 per
cent).
Readily oxidizable substancesI
n a ground-glass-stoppered conical flask introduce 10 g of the substance ( Sodium
propionate.) to be examined.
Add 100 ml of water R and stir to dissolve. Add 25 ml of
sodium hypobromite solution and 10 ml of a 200 g/l solution of sodium acetate, stopper
the flask and allow to stand for 15 min. Add 10 ml of potassium iodide solution and 20
ml of hydrochloric acid while cooling.
Titrate with 0.2 M sodium thiosulphate, adding 2 ml of starch solution R towards the end
of the titration. Carry out a blank titration. The difference between the volumes used
in the 2 titrations is not greater than 2.2 ml.
Iron
Maximum 10 ppm.
10 ml of solution S complies with the limit test for iron.
Heavy metals
Maximum 10 ppm.
12 ml of solution S complies with limit test A. Prepare the standard
using lead standard solution (1 ppm Pb).
Loss on drying
Maximum 0.5 per cent, determined on 1.000 g by heating in an oven at 105C for 3 h.
ASSAY
Dissolve 80.0 mg Sodium propionate in 30 ml of anhydrous acetic acid R. Titrate with 0.1
M perchloric acid, determining the end-point potentiometrically.
1 ml of 0.1 M perchloric acid is equivalent to 9.61 mg of C3H5NaO2.
Sodium Propionate
C3H5NaO2·xH2O
Propanoic acid, sodium salt, hydrate.
Sodium propionate hydrate [6700-17-0]
Anhydrous 96.06 [137-40-6]
Sodium
Propionate, dried at 105 for 2 hours, contains not less than 99.0 percent and not
more than 100.5 percent of C3H5NaO2.
Identification—
A: Infrared Absorption 197K , on un-dried specimen.
B: A solution (1 in 20)
responds to the tests for Sodium.
Alkalinity— Dissolve 2.0 g in 20 mL of water, and add phenolphthalein TS: if
a pink color is produced, it is discharged by 0.60 mL of 0.10 N sulfuric acid.
Water: not more than 1.0%.
Heavy metals— Dissolve 2 g in 1 mL of 1 N acetic acid and sufficient water to
make 25 mL: the limit is 0.001%.
Organic volatile impurities: meets the requirements.
(Official until July
1, 2007)
Assay— Dissolve about 200 mg of Sodium Propionate, previously dried at 105
for 2 hours and accurately weighed, in 50 mL of glacial acetic acid. Add 1 drop of
crystal violet TS, and titrate with 0.1 N perchloric acid VS to a green endpoint.
Perform a blank determination, and make any necessary correction. Each mL of 0.1 N
perchloric acid is equivalent to 9.606 mg of C3H5NaO2.
CH3CH2COONa
C3H5NaO2 Formula weight 96.06
INS: 281 CAS 137-40-6
DESCRIPTION
Sodium Propionate occurs as white or colorless, transparent crystals or as a
granular, crystalline powder. It is hygroscopic in moist air. One gram is soluble in
about 1 mL of water at 25°, in about 0.65 mL of boiling water, and in about 24 mL of
alcohol. The pH of a 1:10 aqueous solution is between 8.0 and 10.5.
Function: Preservative; mold inhibitor.
REQUIREMENTS
Identification:
A. A 1:20 aqueous solution gives positive tests for
Sodium.
B. Upon ignition, a sample yields an alkaline residue that effervesces
with acids.
C. Warm a small sample with sulfuric acid. Propionic acid, recognized
by its odor, evolves.
Assay: Not less than 99.0% and not more than 100.5% of C3H5NaO2 after
drying.
Alkalinity (as Na2CO3): Passes test (about 0.15%).
Iron: Not more than 0.003%.
Lead: Not more than 2 mg/kg.
Water: Not more than 1%.
