(Ph Eur monograph 2041)
C3H5NaO2 96.1 137-40-6
99.0 per cent to 101.0 per cent (dried substance).
Colourless crystals or white powder, slightly hygroscopic.
Freely soluble in water, sparingly soluble in alcohol,
practically insoluble in methylene chloride.
B, C, D.
absorption spectrophotometry (2.2.24).
Comparison: Ph. Eur. reference spectrum of sodium
0.1 g in a mixture of 2 ml of copper sulphate solution R and 2 ml of methylene
chloride R. Shake vigorously and allow to stand. Both the upper and the lower layer
show a blue colour.
C. To 5
ml of solution S (see Tests) add 2 ml of 0.1 M silver nitrate. A white precipitate
S gives reaction (a) of sodium (2.3.1).
Dissolve 10 g in carbon dioxide-free water R prepared from distilled water R and dilute to 100 ml with the same solvent.
Appearance of solution
Solution S is clear (2.2.1) and colourless (2.2.2, Method II).
7.8 to 9.2.
Dilute 1 ml of solution S to 5 ml with water R.
Liquid chromatography (2.2.29).
Dissolve 0.250 g of the substance to be examined in water R 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 R in water R 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 R.
size: l = 0.25 m,
Ø = 4.6 mm,
stationary phase: octadecylsilyl silica
gel for chromatography R (5 µm).
Dilute 1 ml of phosphoric acid R to 1000 ml with water R.
Spectrophotometer at 210 nm.
Reference solution (a):
resolution: minimum 5 between the
peaks due to sodium acetate and sodium propionate.
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),
total: not more than half the
area of the principal peak in the chromatrogram obtained with reference solution (b) (0.5
disregard limit: 0.05 times the area of
the principal peak in the chromatogram obtained with reference solution (b) (0.05 per
Readily oxidisable substances
In a ground-glass-stoppered conical flask introduce 10 g of
the substance to be examined. Add 100 ml of water
R and stir to dissolve. Add 25 ml of sodium hypobromite solution R and
10 ml of a 200 g/l solution of sodium acetate R, stopper the flask and allow to
stand for 15 min. Add 10 ml of potassium iodide solution R and 20 ml of hydrochloric
acid R 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.
Maximum 10 ppm.
10 ml of solution S complies with the limit test for iron.
Heavy metals (2.4.8)
Maximum 10 ppm.
12 ml of solution S complies with limit test A. Prepare the
standard using lead standard solution (1 ppm Pb) R.
Loss on drying (2.2.32)
Maximum 0.5 per cent, determined on 1.000 g by heating in an
oven at 100C105 C for 3 h.
Dissolve 80.0 mg in 30 ml of anhydrous acetic acid R.
Titrate with 0.1 M perchloric acid, determining the end-point potentiometrically (2.2.20).
1 ml of 0.1 M perchloric acid is equivalent to 9.61 mg
In an airtight container .
Action and use