Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Zinc Oxide Part 4, Monographs for Reagent Chemicals: General Descriptions, Specifications, and Tests eISBN: 9780841230460 Tom Tyner Chair, ACS Committee on Analytical Reagents James Francis Secretary, ACS Committee on Analytical Reagents
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ABSTRACT This monograph for Zinc Oxide provides, in addition to common physical constants, a general description including typical appearance, applications, and aqueous solubility. The monograph also details the following specifications and corresponding tests for verifying that a substance meets ACS Reagent Grade specifications including: Assay, Insoluble in Dilute Sulfuric Acid, Alkalinity, Chloride, Nitrate, Sulfur Compounds, Calcium, Iron, Lead, Magnesium, Manganese, Potassium, and Sodium.
ZnO
Formula Wt 81.38
CAS No. 1314-13-2
GENERAL DESCRIPTION Typical appearance . . . . . . . . . . . . . . . . . . . white solid Applications . . . . . . . . . . . . . . . . . . . . . . . . preparation of zinc standard solutions Aqueous solubility . . . . . . . . . . . . . . . . . . . . practically insoluble
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥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
© 2017 American Chemical Society
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ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4428 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Potassium (K) . . . . . . . . . . . . . . . . . . . . . . . 0.01% Sodium (Na) . . . . . . . . . . . . . . . . . . . . . . . . 0.05%
TESTS Assay
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(By complexometric titration of zinc). Weigh accurately 0.25 g, and transfer to a 500 mL beaker. Dissolve in 15 mL of hydrochloric acid (1:1), and dilute to about 300 mL with water. Add 0.15 mL of methyl red indicator solution, and neutralize (to a yellow color) by dropwise addition of 10% sodium hydroxide reagent solution. Add 15 mL of hexamethylenetetramine reagent solution and 50 mg of xylenol orange indicator mixture. Titrate with standard 0.1 M EDTA volumetric solution to a color change of purple-red to lemon yellow. One milliliter of 0.1 M EDTA corresponds to 0.008138 g of ZnO.
Insoluble in Dilute Sulfuric Acid Dissolve 10 g by heating in a covered beaker on a steam bath with 160 mL of dilute sulfuric acid (1:15) for 1 h. Filter through a tared filtering crucible, wash thoroughly, and dry at 105 °C.
Alkalinity Suspend 2 g in 20 mL of water, boil for 1 min, and filter. Add 0.10 mL of phenolphthalein indicator solution to 10 mL of the filtrate. No red color should be produced.
Chloride [Part 2: Colorimetry and Turbidimetry; Chloride]. Suspend 1.0 g in 20 mL of water, and dissolve by adding 3 mL of nitric acid.
Nitrate [Part 2: Colorimetry and Turbidimetry; Nitrate; Procedure for Nitrate, Method 1 (Brucine Sulfate)]. For sample solution A, dissolve 0.5 g of sample in 5 mL of hydrochloric acid (1:1). For control solution B, use 5 mL of hydrochloric acid (1:1) and 1.5 mL of nitrate ion (NO3) standard solution.
Sulfur Compounds Suspend 5.0 g in 50 mL of water, and add about 50 mg of sodium carbonate and 1 mL of bromine water. Boil for 5 min, cautiously add hydrochloric acid in small portions until the zinc oxide is dissolved, then add 1 mL more of the acid. Filter, wash, and dilute the filtrate with water to about 150 mL. Heat the filtrate to boiling, add 5 mL of 12% barium chloride reagent solution, digest in a covered beaker on a hot plate (~100 °C) for 2 h, and allow to stand for at least 8 h. If a precipitate is formed, filter, wash two or three times with dilute hydrochloric acid (1:99), complete the washing with water alone, and ignite. Correct for the weight obtained in a complete blank test.
© 2017 American Chemical Society
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ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4428 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Calcium, Iron, Lead, Magnesium, Manganese, Potassium, and Sodium (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
For the Determination of Calcium, Iron, Lead, Magnesium, Manganese, Potassium, and Sodium
S a m p l e S t o c k S o l u t i o n . Dissolve 10.0 g in 10 mL of hydrochloric acid in a 100 mL volumetric flask, and dilute with water to volume (1 mL = 0.10 g).
For the Determination of Iron and Lead
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Element
Wavelength (nm)
Sample Wt (g)
Standard Added (mg)
Flame Type*
Background Correction
Ca
422.7
0.80
0.02; 0.04
N/A
No
Fe
248.3
2.0
0.02; 0.04
A/A
Yes
Pb
217.0
2.0
0.05; 0.10
A/A
Yes
Mg
285.2
0.20
0.005; 0.01
A/A
Yes
Mn
279.5
2.0
0.01; 0.02
A/A
Yes
K
766.5
0.20
0.01; 0.02
A/A
No
Na
589.0
0.04
0.01; 0.02
A/A
No
*A/A is air/acetylene; N/A is nitrous oxide/acetylene.
© 2017 American Chemical Society
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ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4428 ACS Reagent Chemicals, Part 4
