Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Zinc Acetate Dihydrate 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
ABSTRACT This monograph for Zinc Acetate Dihydrate provides, in addition to common physical constants, a general description including typical appearance, applications, change in state (approximate), 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, pH of a 5% Solution at 25.0 °C, Insoluble Matter, Chloride, Sulfate, Calcium, Magnesium, Potassium, Sodium, Lead, Iron, and Lead.
(CH3COO)2Zn • 2H2O
Formula Wt 219.50
CAS No. 5970-45-6
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
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colorless or white solid determination of albumin, tannin, urobilin, phosphate, and blood melting point, 327 °C 43 g in 100 mL at 20 °C
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98.0–101.0% (CH3COO)2Zn · 2H2O pH of a 5% solution at 25.0 °C . . . . . . . . . . . . 6.0–7.0 Maximum Allowable Insoluble matter . . . . . . . . . . . . . . . . . . . . . 0.005% Chloride (Cl) . . . . . . . . . . . . . . . . . . . . . . . 5 ppm Sulfate (SO4) . . . . . . . . . . . . . . . . . . . . . . . 0.005% Calcium (Ca) . . . . . . . . . . . . . . . . . . . . . . . 0.005% Magnesium (Mg) . . . . . . . . . . . . . . . . . . . . . 0.005% Potassium (K) . . . . . . . . . . . . . . . . . . . . . . . 0.01% Sodium (Na) . . . . . . . . . . . . . . . . . . . . . . . . 0.05% Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 5 ppm Lead (Pb) . . . . . . . . . . . . . . . . . . . . . . . . . 0.002%
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4426 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
TESTS Assay (By complexometric titration for zinc). Weigh accurately about 0.8 g, transfer to a 500 mL beaker, and dilute to about 300 mL with water. 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 0.02195 g of (CH3COO)2Zn 2H2O.
pH of a 5% Solution at 25.0 °C [Part 2: Direct Electrometric Methods; pH Potentiometry; pH Range; Procedure for pH of a 5% Solution at 25.0 °C].
Insoluble Matter [Part 2: Gravimetric Methods; Insoluble Matter]. Use 20 g dissolved in a mixture of 2 mL of glacial acetic acid and 200 mL of water.
Chloride [Part 2: Colorimetry and Turbidimetry; Chloride]. Use 2.0 g.
Sulfate Dissolve 20 g in 200 mL of water, add 1 mL of hydrochloric acid, filter, heat to boiling, and add 10 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 forms, filter, wash with water containing about 0.2% hydrochloric acid, wash finally with plain water, and ignite. Correct with a blank analyzed concomitantly. One gram of BaSO4 so obtained corresponds to 0.41 g of sulfate ion (SO4).
Calcium, Magnesium, Potassium, Sodium, and Lead (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
For the Determination of Calcium, Magnesium, Potassium, Sodium, and Lead
S a m p l e S t o c k S o l u t i o n . Dissolve 10.0 g in water in a 100 mL volumetric flask, add 0.5 mL of hydrochloric acid, and dilute with water to the mark (1 mL = 0.10 g).
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4426 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
For the Determination of Calcium, Magnesium, Potassium, Sodium, and Lead
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
Mg
285.2
0.20
0.005; 0.01
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.
Iron [Part 2: Colorimetry and Turbidimetry; Iron; Procedure for Iron, Method 1 (Ammonium Thiocyanate)]. Use 2.0 g.
Lead [Part 2: Direct Electrometric Methods; Specific Polarographic Procedures; Procedure for Lead and Cadmium]. Use 5.0 g of sample and 0.25 mL of hydrochloric acid. For the standard, add 0.10 mg of lead ion (Pb).
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4426 ACS Reagent Chemicals, Part 4
