General Provisions Standard for Manufacturing and
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Standard Solution Appendix
Name
Content
Definition
Description
Identification
Purity
Assay
Permitted Use Level
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A. Synthetic Additives
B. Natural Additives
C. Mixture Additives
Standard and Specification > Synthetic Additives > Ammonium Persulfate
14. Ammonium Persulfate  
Chemical Formula (NH4)2S2O8 
Molecular Weight 228.20 
[Compositional Specifications of Ammonium Persulfate]
Content Ammonium Persulfate should contain not less than 95.0% of ammonium persulfate ((NH4)2S2O8). 
Description Ammonium Persulfate occurs as colorless crystals or as a white crystalline powder.  
Identification (1) To 0.5 g of Ammonium Persulfate. add 5 ml of sodium hydroxide solution, and heat. A gas with an odor of ammonia is evolved. This gas changes the color of a red litmus paper wetted with water to blue.

(2) Add 2~3 drops of manganese sulfate solution (1→100) to 5 ml of diluted sulfuric acid. Add 1 drop of silver nitrate solution and 0.2 g of Ammonium Persulfate, and warm. A pink color develops. 
Purity (1) Clarity and color of solution : When Ammonium Persulfate 1 g is dissolved in 10 ml of water, the solution should be colorless and almost clear.

(2) Arsenic : 0.5 g of Ammonium Persulfate is dissolved in 5 ml of water, where 1 ml of sulfuric acid and 10 ml of sulfurous acid are added. The resulting solution is concentrated to approximately 2 ml by evaporation, which is diluted to 10 ml with water. 5 ml of this solution is tested for arsenic. The content of arsenic should not be more than 4ppm.
(3) Heavy metals : 1 g of Ammonium Persulfate is strongly heated first, then gently is heated until the generation of white smoke stops. To the residues, 1 ml of hydrochloric acid and 5 drops of nitric acid are added, which is evaporated to dryness in a water bath. 5 ml of dilute hydrochloric acid is added to the resulting residue, which is evaporated again in a water bath. The residues are dissolved in 2 ml of dilute acetic acid and approximately 20 ml of water, Test Solution. This Test Solution is tested for heavy metals and its content should not be more than 30ppm. 
Residue on Ignition First, this item is gently ignited, then strongly did until the weight becomes constant. The residue should not be more than 0.2%. 
Assay Water is added to precisely weighed approximately 1.5 g of Ammonium Persulfate to bring the total volume to 250 ml, 50 ml of which is mixed with 40 ml of 0.1 N ammonium ferrous sulfate solution and 5 ml of phosphoric acid. The excess amount of ammonium ferrous sulfate is titrated with 0.1 N potassium permanganate solution. Separately, a blank test is carried out by the same method.

0.1 N ammonium ferrous solution 1 ml = 11.41 mg (NH4)2S2O8. 
Permitted Use Level of Ammonium Persulfate and Ingredients Containing it Ammonium Persulfate should only be used for wheat flour. Its content should not be more than 0.3 g as ammonium persulfate per 1 kg of wheat flour.