New specifications prepared at the 53rd JECFA (1999) and published in FNP 52 Add 7 (1999). Information required on technological effect and actual uses in foods and levels of metallic impurities including lead. | ||
SYNONYMS |
Glauber's salt, INS No. 514i | |
DEFINITION |
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C.A.S. number |
7757-82-6 (Anhydrous) | |
Chemical formula |
Na2SO4 � xH2O (x = 0 or 10) | |
Formula weight |
142.04 (Anhydrous)
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Assay |
Not less than 99.0 % on the dried basis | |
DESCRIPTION |
Colourless crystals or fine, white crystalline powder. The decahydrate is efflorescent. | |
FUNCTIONAL USES |
Information required | |
CHARACTERISTICS |
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IDENTIFICATION |
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Solubility (FNP 5) |
Freely soluble in water; practically insoluble in ethanol | |
Test for sodium (FNP 5) |
Passes test | |
Test for sulfate (FNP 5) |
Passes test | |
PURITY |
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Loss on drying (FNP 5) |
Anhydrous: Not more than 1% (105�, 4 h) | |
Selenium (FNP 5) |
Not more than 30 mg/kg | |
Lead (FNP5) |
Not more than 2 mg/kg | |
Metallic impurities |
Information required | |
METHOD OF ASSAY |
Weigh accurately about 0.5 g of the dried sample, dissolve in 200 ml of water, add 1 ml of hydrochloric acid and heat to boiling. Gradually add, in small portions and while stirring constantly, an excess of hot barium chloride TS (about 10 ml), and heat the mixture on a steam bath for 1 h. Collect the precipitate on a filter, wash until free from chloride, dry, ignite and weigh. The weight of the barium sulfate so obtained, multiplied by 0.6086 corresponds to the equivalent amount of Na2SO4. |