Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Strontium Chloride Hexahydrate 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 Strontium Chloride Hexahydrate 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, Sulfate, Barium, Calcium, Magnesium, Heavy Metals, and Iron.
SrCl2 • 6H2O
Formula Wt 266.61
CAS No. 10025-70-4
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
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white to off-white solid preparation of strontium standard solutions melting point, 61 °C when rapidly heated 198 g in 100 mL at 40 °C
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99.0–103.0% SrCl2 · 6H2O pH of a 5% solution at 25.0 °C . . . . . . . . . . . . 5.0–7.0 Maximum Allowable Insoluble matter . . . . . . . . . . . . . . . . . . . . . 0.005% Sulfate (SO4) . . . . . . . . . . . . . . . . . . . . . . . 0.001% Barium (Ba) . . . . . . . . . . . . . . . . . . . . . . . . 0.05% Calcium (Ca) . . . . . . . . . . . . . . . . . . . . . . . 0.05% Magnesium (Mg) . . . . . . . . . . . . . . . . . . . . . 2 ppm Heavy metals (by ICP–OES) . . . . . . . . . . . . . . 5 ppm Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 5 ppm
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4380 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
TESTS Assay (By complexometric titration of strontium). Weigh accurately about 1.0 g of sample, transfer to a 250 mL beaker, and dissolve in 50 mL of water. Add 5 mL of diethylamine and 35 mg of methylthymol blue indicator mixture. Titrate immediately with 0.1 M EDTA volumetric solution until the blue color turns to colorless or gray. One milliliter of 0.1 M EDTA corresponds to 0.02666 g of SrCl2 · 6H2O.
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 20.0 g dissolved in 150 mL of water.
Sulfate [Part 2: Colorimetry and Turbidimetry; Sulfate; Procedure for Sulfate, Method 1]. Use a 5.0 g sample. Allow 30 min for turbidity to form.
Barium, Calcium, and Magnesium (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
For the Determination of Barium, Calcium, and Magnesium
S a m p l e S t o c k S o l u t i o n . Dissolve 10.0 g of sample with water in a 100 mL volumetric flask, add 5 mL of nitric acid, and dilute to the mark with water (1 mL = 0.10 g).
For the Determination of Barium, Calcium, and Magnesium
Element
Wavelength (nm)
Sample Wt (g)
Standard Added (mg)
Flame Type*
Background Correction
Ba
553.6
0.20
0.10; 0.20
N/A
No
Ca
422.7
0.10
0.05; 0.10
N/A
No
Mg
285.2
2.50
0.005; 0.01
A/A
No
*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 2.0 g sample.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4380 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Iron Dissolve 2.0 g in 25 mL of water, add 2 mL of hydrochloric acid and 0.10 mL of 0.1 N potassium permanganate volumetric solution, and allow to stand for 5 min. Add 3 mL of ammonium thiocyanate reagent solution. Any red color should not exceed that produced by 0.01 mg of iron in an equal volume of solution containing the quantities of reagents used in the test.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4380 ACS Reagent Chemicals, Part 4
