Zinc Oxide Pharmaceutical Grade USP34 CAS NO.1314-13-2

Idex item

Standard

Assay(ZnO)

99.0%-100.5%

identification

A:When stongly heated,it assumes a yellow color

that disappears on cooling

B:Asolution of it in a slight excess of 3N

hydrochloric acid responds to the tests for

Zinc<191>

Alkalinity

Mix 1.0g with 10ml of hot water,add 2 drops of

phenolphthalein TS,and filter;if a red color

is produced.not more than 0.30ml of 0.10 N

hydrochloric acid is required to discharge it

Loss on ignition

not more than 1.0%

As

not more than 6ppm

Carbonate and color of solution

Mix 2.0g with 10ml of water,add 30ml of 2N

sulfuric acid,and heat on a steam bath,with

contant stirring;no effervescence occours

and the resulting solution is clear and colorless

Lead(Pb)

Add 2g to 20ml of water ,stir well ,add 5 ml of glacial acetic acid, and warm on a steam bath until solution is effected,the addition of 5 drops of potassium chromate TS produces no turbidity or precipitate

Iron and other heavy metals

Cooled 5ml portions of the solution obtained in the test for carbonate and color of solution yield white precipitates with potassium ferrocyanide TS and with sodium sulfide TS

Assay

??Dissolve about 1.5 g of freshly ignited Zinc Oxide, accurately weighed, and 2.5 g of ammonium chloride in 50.0 mL of 1 N sulfuric acid VS with the aid of gentle heat, if necessary.

When solution is complete, add methyl orange TS, and titrate the excess sulfuric acid with 1 N sodium hydroxide VS. Each mL of 1 N sulfuric acid is equivalent to 40.69 mg of ZnO.

Idex item

Standard

Assay(ZnO)

99.0%-100.5%

identification

A:When stongly heated,it assumes a yellow color

that disappears on cooling

B:Asolution of it in a slight excess of 3N

hydrochloric acid responds to the tests for

Zinc<191>

Alkalinity

Mix 1.0g with 10ml of hot water,add 2 drops of

phenolphthalein TS,and filter;if a red color

is produced.not more than 0.30ml of 0.10 N

hydrochloric acid is required to discharge it

Loss on ignition

not more than 1.0%

As

not more than 6ppm

Carbonate and color of solution

Mix 2.0g with 10ml of water,add 30ml of 2N

sulfuric acid,and heat on a steam bath,with

contant stirring;no effervescence occours

and the resulting solution is clear and colorless

Lead(Pb)

Add 2g to 20ml of water ,stir well ,add 5 ml of glacial acetic acid, and warm on a steam bath until solution is effected,the addition of 5 drops of potassium chromate TS produces no turbidity or precipitate

Iron and other heavy metals

Cooled 5ml portions of the solution obtained in the test for carbonate and color of solution yield white precipitates with potassium ferrocyanide TS and with sodium sulfide TS

Assay

??Dissolve about 1.5 g of freshly ignited Zinc Oxide, accurately weighed, and 2.5 g of ammonium chloride in 50.0 mL of 1 N sulfuric acid VS with the aid of gentle heat, if necessary.

When solution is complete, add methyl orange TS, and titrate the excess sulfuric acid with 1 N sodium hydroxide VS. Each mL of 1 N sulfuric acid is equivalent to 40.69 mg of ZnO.