Ph Eur
ZnO -- 81.4 -- 1341-13-2
DEFINITION
Content: 99.0 per cent to 100.5 per cent (ignited substance).
CHARACTERS
Appearance: Soft, white or faintly yellowish-white, amorphous powder, free from gritty particles.
Solubility: Practically insoluble in water and in ethanol (96 per cent). It dissolves in dilute mineral acids.
IDENTIFICATION
A. It becomes yellow when strongly heated; the yellow colour disappears on cooling.
B. Dissolve 0.1 g in 1.5 ml of dilute hydrochloric acid and dilute to 5 ml with water. The solution gives the reaction of zinc.
TESTS
Alkalinity: Shake 1.0 g with 10 ml of boiling water. Add 0.1 ml of PhPh solution and filter. If the filtrate is red, not more than 0.3 ml of 0.1 M hydrochloric acid is required to change the colour of the indicator.
Carbonates and substances insoluble in acids: Dissolve 1.0 g in 15 ml of dilute hydrochloric acid. It dissolves without effervescence and the solution is not more opalescent than reference suspension and is colourless.
Arsenic: Maximum 5 ppm, determined on 0.2 g.
Cadmium: Maximum 10.0 ppm.
Iron: Maximum 200 ppm.
Lead: Maximum 50.0 ppm.
Loss on ignition: Maximum 1.0 per cent, determined on 1.00 g by ignition to constant mass at 500 ±50C.
Zinc Oxide IP Grade is also offered.
ZnO 81.39 -- [1314-13-2].
Zinc Oxide, freshly ignited, contains not less than 99.0 percent and not more than 100.5 percent of ZnO.
Packaging and storage: Preserve in well-closed containers.
Identification:
A: When strongly heated, it assumes a yellow color that disappears on cooling.
B: A solution of it in a slight excess of 3 N hydrochloric acid responds to the tests for Zinc .
Alkalinity: Mix 1.0 g with 10 mL of hot water, add 2 drops of PhPh, and filter: if a red color is produced, not more than 0.30 mL of 0.10 N hydrochloric acid is required to discharge it.
Loss on ignition: Weigh accurately about 2 g, and ignite at 500 to constant weight: it loses not more than 1.0% of its weight.
Carbonate and color of solution: Mix 2.0 g with 10 mL of water, add 30 mL of 2 N sulfuric acid, and heat on a steam bath, with constant stirring: no effervescence occurs and the resulting solution is clear and colorless.
Arsenic: 6 ppm.
Lead: Add 2 g to 20 mL 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 produces no turbidity or precipitate.
Iron and other heavy metals: Cool two separate 5-mL portions of the solution obtained in the test for Carbonate and color of solution. White precipitates are formed when potassium ferrocyanide is added to the first portion and when sodium sulfide is added to the second portion.
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 with the aid of gentle heat, if necessary. When solution is complete, add methyl orange and titrate the excess sulfuric acid with 1 N sodium hydroxide. Each mL of 1 N sulfuric acid is equivalent to 40.69 mg of ZnO.
ZnO Formula wt 81.38
CAS: [1314-13-2]
DESCRIPTION
Zinc Oxide occurs as a fine, white, amorphous powder. It gradually absorbs carbon dioxide from the air. It is insoluble in water and in alcohol, and is soluble in dilute acids and in strong bases.
Function: Nutrient.
REQUIREMENTS
Identification
A. When strongly heated, a sample assumes a yellow color that disappears on cooling.
B. A solution of sample in a slight excess of 3 N hydrochloric acid gives positive tests for Zinc, Appendix IIIA.
Assay: Not less than 99.0% of ZnO after ignition.
Alkalinity: Passes test.
Cadmium: Not more than 3 mg/kg.
Lead: Not more than 10 mg/kg.
Loss on Ignition: Not more than 1.0%.
Substances Not Precipitated by Sulfide: Not more than 0.5%.
ZnO
Formula Wt 81.39
CAS Number 1314-13-2
REQUIREMENTS
Assay: minimum 99.0% ZnO
MAXIMUM ALLOWABLE
Insoluble in dilute sulfuric acid: 0.01%
Alkalinity: Passes test
Chloride (Cl): 0.001%
Nitrate (NO3): 0.003%
Sulfur compounds (as SO4): 0.01%
Calcium (Ca): 0.005%
Iron (Fe): 0.001%
Lead (Pb): 0.005%
Magnesium (Mg): 0.005%
Manganese (Mn): 5 ppm
Potassium (K): 0.01%
Sodium (Na): 0.05%
