Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Sodium Acetate (Sodium Acetate, Anhydrous) 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 Sodium Acetate 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, Loss on Drying, Chloride, Phosphate, Sulfate, Calcium, Magnesium, Heavy Metals, and Iron.
CH3COONa
Formula Wt 82.03
CAS No. 127-09-3
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
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white solid buffers melting point, 324 °C 46.5 g in 100 mL at 20 °C
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥99.0% C2H3O2Na pH of a 5% solution at 25.0 °C . . . . . . . . . . . . 7.0–9.2 Maximum Allowable Insoluble matter . . . . . . . . . . . . . . . . . . . . . 0.01% Loss on drying . . . . . . . . . . . . . . . . . . . . . . 1.0% Chloride (Cl) . . . . . . . . . . . . . . . . . . . . . . . 0.002% Phosphate (PO4) . . . . . . . . . . . . . . . . . . . . . 0.001% Sulfate (SO4) . . . . . . . . . . . . . . . . . . . . . . . 0.003% Calcium (Ca) . . . . . . . . . . . . . . . . . . . . . . . 0.005% Magnesium (Mg) . . . . . . . . . . . . . . . . . . . . . 0.002%
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4326 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Heavy metals (by ICP–OES) . . . . . . . . . . . . . . 0.001% Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.001%
TESTS Assay (Total alkalinity by nonaqueous titration). Weigh accurately about 0.3 g of sample into a 125 mL flask, and dissolve in 50 mL of acetic acid and 5 mL of acetic anhydride. Prepare a blank using 50 mL of acetic acid and 5 mL of acetic anhydride. Allow to stand for 15 min. Add 0.10 mL of crystal violet indicator solution to both flasks, and titrate with 0.1 N perchloric acid in glacial acetic acid volumetric solution until the solution color changes from violet to emerald green. One milliliter of 0.1 N perchloric acid corresponds to 0.008203 g of CH3COONa.
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 150 mL of water.
Loss on Drying Weigh accurately about 2 g in a tared, preconditioned weighing bottle, and dry at 120 °C to constant weight.
Chloride [Part 2: Colorimetry and Turbidimetry; Chloride]. Use 0.50 g.
Phosphate [Part 2: Colorimetry and Turbidimetry; Phosphate; Procedure for Phosphate, Method 2 (Extracted Molybdenum Blue)]. Dissolve 2.0 g in 10 mL of nitric acid, and evaporate to dryness on a hot plate (~100 °C). Add 10 mL of nitric acid, and repeat the evaporation. Dissolve in 80 mL of water, add 0.5 g of ammonium molybdate, and adjust the pH to 1.8 (using a pH meter) with dilute hydrochloric acid (1: 9). Heat to boiling, cool, add 10 mL of hydrochloric acid, and continue as described. Carry along a standard containing 0.02 mg of phosphate ion (PO4) treated in the same manner as the sample after the addition of 80 mL of water.
Sulfate [Part 2: Colorimetry and Turbidimetry; Sulfate; Procedure for Sulfate, Method 1]. Allow 30 min for turbidity to form.
Calcium and Magnesium (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4326 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
For the Determination of Calcium and Magnesium
S a m p l e S t o c k S o l u t i o n . Dissolve 5.0 g in 80 mL of water, and transfer to a 100 mL volumetric flask. Dilute to the mark with water (1 mL = 0.05 g).
For the Determination of Calcium and Magnesium
Element
Wavelength (nm)
Sample Wt (g)
Standard Added (mg)
Flame Type*
Background Correction
Ca
422.7
0.50
0.025; 0.05
N/A
No
Mg
285.2
0.50
0.01; 0.02
A/A
Yes
*A/A is air/acetylene; N/A is nitrous oxide/acetylene.
Heavy Metals ([Part 2: Trace and Ultratrace Elemental Analysis; Inductively Coupled Plasma−Optical Emission Spectroscopy (ICP–OES); Calculation of Heavy Metals (by ICP–OES) Results], by ICP–OES). Use 1.0 g sample.
Iron [Part 2: Colorimetry and Turbidimetry; Iron; Procedure for Iron, Method 1 (Ammonium Thiocyanate)]. Dissolve 1.0 g in 50 mL of dilute hydrochloric acid (1:24), and use the solution without further acidification.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4326 ACS Reagent Chemicals, Part 4
