Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Potassium Sodium Tartrate Tetrahydrate (2,3-Dihydroxybutanedioic Acid, Potassium Sodium Salt, Tetrahydrate)
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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 Potassium Sodium Tartrate Tetrahydrate 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, Phosphate, Sulfate, Ammonium, Calcium, Heavy Metals, and Iron.
KNaC4H4O6•4H2O
Formula Wt 282.22
CAS No. 6381-59-5
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
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colorless or white solid constituent of Fehling’s solution melting point, 75 °C 111 g in 100 mL at 25 °C
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99.0–102.0% KNaC4H4O6 · 4H2O pH of a 5% solution at 25.0 °C . . . . . . . . . . . . 6.0–8.5 Maximum Allowable Insoluble matter . . . . . . . . . . . . . . . . . . . . . 0.005% Chloride (Cl) . . . . . . . . . . . . . . . . . . . . . . . 0.001% Phosphate (PO4) . . . . . . . . . . . . . . . . . . . . . 0.002% Sulfate (SO4) . . . . . . . . . . . . . . . . . . . . . . . 0.005%
© 2017 American Chemical Society
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ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4307 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Ammonium (NH4) . . Calcium (Ca) . . . . . Heavy metals (as Pb) Iron (Fe) . . . . . . . .
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0.002% 0.005% 5 ppm 0.001%
TESTS Assay
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(Total alkalinity by nonaqueous titration). Weigh accurately about 0.5 g, and mix with 3 mL of 96% formic acid to dissolve. Add 5 mL of acetic anhydride and 50 mL of glacial acetic acid. Titrate with 0.1 N perchloric acid in glacial acetic acid volumetric solution to a green end point with crystal violet indicator. One milliliter of 0.1 N perchloric acid corresponds to 0.01411 g of KNaC4H4O6 · 4H2O.
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 in 200 mL of water.
Chloride [Part 2: Colorimetry and Turbidimetry; Chloride]. Use 1.0 g.
Phosphate [Part 2: Colorimetry and Turbidimetry; Phosphate; Procedure for Phosphate, Method 1 (Direct Molybdenum Blue)]. Ignite 1.0 g in a platinum dish. Dissolve the residue in 5 mL of water, add 5 mL of nitric acid, and evaporate to dryness. Dissolve the residue in 25 mL of approximately 0.5 N sulfuric acid, and continue as described.
Sulfate To 5.0 g of sample, add 4 mL of hydrochloric acid and 8 mL of 30% hydrogen peroxide. Digest in a covered beaker on a hot plate (~100 °C) until reaction ceases. Carefully rinse down the cover glass and sides of the beaker with about 5 mL of water. Add 4 mL of hydrochloric acid and 3 mL of 30% hydrogen peroxide, and evaporate to dryness. Add 10 mL of water, and evaporate to dryness. Dissolve the residue in 5 mL of 10% hydrochloric acid, and dilute to 25 mL with water (5 mL = 1 g). For the sample, take 15 mL, and for the control, take 5 mL of the sample solution. Add 0.10 mg of sulfate ion (SO4) to each. Dilute both solutions to 25 mL, add 1 mL of 12% barium chloride reagent solution to each, and compare after 10 min. Sample solution turbidity should not exceed that of the control solution.
© 2017 American Chemical Society
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ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4307 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Ammonium Dissolve 1.0 g in 50 mL of water. To 25 mL of the solution, add 2 mL of 10% sodium hydroxide reagent solution, dilute with water to 50 mL, and add 2 mL of Nessler reagent. Any color should not exceed that produced by 0.01 mg of ammonium ion (NH4) in an equal volume of solution containing the quantities of reagents used in the test.
Calcium (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
For the Determination of Calcium
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S a m p l e S t o c k S o l u t i o n . Dissolve 4.0 g, and dilute to 100 mL with water in a volumetric flask (1 mL = 0.04 g).
For the Determination of Calcium
Element
Wavelength (nm)
Sample Wt (g)
Standard Added (mg)
Flame Type*
Background Correction
Ca
422.7
0.40
0.02; 0.04
N/A
No
*N/A is nitrous oxide/acetylene.
Heavy Metals [Part 2: Colorimetry and Turbidimetry; Heavy Metals (as Lead); Procedure for Heavy Metals, Method 1]. Dissolve 8.0 g in about 20 mL of water, and dilute with water to 32 mL. Use 24 mL to prepare the sample solution, and use the remaining 8.0 mL to prepare the control solution.
Iron [Part 2: Colorimetry and Turbidimetry; Iron; Procedure for Iron, Method 1 (Ammonium Thiocyanate)]. Use 1.0 g.
© 2017 American Chemical Society
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ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4307 ACS Reagent Chemicals, Part 4
