Zinc Oxide - ACS Reagent Chemicals (ACS Publications)

Feb 28, 2017 - This monograph for Zinc Oxide provides, in addition to common physical constants, a general description including typical appearance, ...
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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

Downloaded by CORNELL UNIV on May 22, 2017 | http://pubs.acs.org Publication Date (Web): February 28, 2017 | doi: 10.1021/acsreagents.4428

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

C

ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.

DOI:10.1021/acsreagents.4428 ACS Reagent Chemicals, Part 4