Packaging and storage
Preserve in tight containers.
To 5 mL of a solution (1 in 100) add 1 mL of calcium chloride TS
: a voluminous, gelatinous precipitate is formed immediately.
To 10 mL of a solution (1 in 100) add 1 mL of 4 N sulfuric acid: a heavy, gelatinous precipitate is formed.
Microbial limits 61
The total bacterial count does not exceed 200 cfu per g, and the tests for Salmonella
species and Escherichia coli
Loss on drying 731
Dry it at 105
for 4 hours: it loses not more than 15.0% of its weight.
Total ash 561
Proceed as directed for Total Ash
under Methods of Analysis
, carefully igniting about 3 g, accurately weighed, in a tared platinum dish, until the residue is thoroughly carbonized (about 5 minutes), and then igniting in a muffle furnace at a temperature of 800 ± 25
until the carbon is completely burned off (approximately 75 minutes): between 18.0% and 27.0% of ash is found, calculated on the dried basis.
Add 1.0 g to 20 mL of nitric acid in a 250-mL conical flask, mix, and heat carefully until the Sodium Alginate is dissolved. Continue the heating until the volume is reduced to about 7 mL. Cool rapidly to room temperature, transfer to a 100-mL volumetric flask, and dilute with water to volume. A 50.0-mL portion of this solution contains not more than 5 µg of lead (corresponding to not more than 0.001% of Pb), 15 mL of ammonium citrate solution, 3 mL of potassium cyanide solution, and 0.5 mL of hydroxylamine hydrochloride solution being used for the test. After the first dithizone extractions, wash the combined chloroform layers with 5 mL of water, discarding the water layer and continuing in the usual manner by extracting with 20 mL of 0.2 N nitric acid.
Heavy metals, Method II 231
Conduct the ignition in a platinum crucible, and use nitric acid in place of sulfuric acid to wet the test specimen: the limit is 0.004%.
Proceed as directed for Procedure
under Alginates Assay 311
, using about 250 mg of Sodium Alginate, accurately weighed. Each mL of 0.2500 N sodium hydroxide consumed is equivalent to 27.75 mg of sodium alginate.