Assay

Not less than 99.0 % on the dried basis

DESCRIPTION

White or colourless crystals

FUNCTIONAL USES

Preservative, antimould and antirope agent

CHARACTERISTICS

IDENTIFICATION

Solubility

Freely soluble in water, soluble in ethanol

Positive test for potassium

Passes test

Positive test for propionate

Warm the sample with sulfuric acid. The propionic acid evolved may be recognized by its odour.

Positive test for alkali salt of organic acid

Ignite the sample at a relatively low temperature. The alkaline residue effervesces with acid.

PURITY

Loss on drying

Not more than 4% (105°, 2h)

Water-insoluble matter

Not more than 0.1 %
See description under TESTS

pH

7.5 - 10.5 (1 in 10 soln)

Iron

Not more than 30 mg/kg
Test 0.5 g of the sample as described in the Limit Test using 1.5 ml of Iron Standard Solution (15 m g), in the control.

Lead

Not more than 5 mg/kg
Prepare a sample solution as directed for organic compounds in the Limit Test, using 5 m g of lead ion (Pb) in the control.