Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Cadmium Sulfate, 8/3-Hydrate (Cadmium Sulfate, Crystals) 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 Cadmium Sulfate, 8/3-Hydrate 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, Insoluble Matter, Chloride, Nitrate, Nitrite, Calcium, Copper, Lead, Potassium, Sodium, and Zinc, and Iron.
CdSO4·8/3H2O
Formula Wt 256.50
CAS No. 7790-84-3
GENERAL DESCRIPTION Typical appearance . . . . . . . . . . . . . . . . . . . colorless solid Applications . . . . . . . . . . . . . . . . . . . . . . . . preparation of cadmium standards Change in state (approximate) . . . . . . . . . . . . on heating, loses water above 40 °C, forming monohydrate by 80 °C; does not become anhydrous on further heating Aqueous solubility . . . . . . . . . . . . . . . . . . . . freely soluble
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98.0–102.0% CdSO4·8/3H2O Maximum Allowable Insoluble matter . . . . . . . . . . . . . . . . . . . . . 0.005% Chloride (Cl) . . . . . . . . . . . . . . . . . . . . . . . 0.001% Nitrate and nitrite (as NO3) . . . . . . . . . . . . . . 0.003% Calcium (Ca) . . . . . . . . . . . . . . . . . . . . . . . 0.005% Copper (Cu) . . . . . . . . . . . . . . . . . . . . . . . . 0.002% Lead (Pb) . . . . . . . . . . . . . . . . . . . . . . . . . 0.003% Potassium (K) . . . . . . . . . . . . . . . . . . . . . . . 0.01% Sodium (Na) . . . . . . . . . . . . . . . . . . . . . . . . 0.02%
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4074 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Zinc (Zn) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.05% Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.001%
TESTS Assay (By complexometric titration of cadmium). Weigh accurately 1.0 g, transfer to a 400 mL beaker, and dissolve in 175 mL of water. Add 15 mL of hexamethylenetetramine reagent solution and 50 mg of xylenol orange indicator mixture. Titrate with 0.1 M EDTA volumetric solution to a color or red-purple to lemon yellow. One milliliter of 0.1 M EDTA corresponds to 0.02565 of CdSO4·8/3H2O.
Insoluble Matter [Part 2: Gravimetric Methods; Insoluble Matter]. Use 20 g dissolved in 150 mL of water.
Chloride [Part 2: Colorimetry and Turbidimetry; Chloride]. Use 1.0 g.
Nitrate and Nitrite [Part 2: Colorimetry and Turbidimetry; Nitrate; Procedure for Nitrate, Method 1 (Brucine Sulfate)]. For sample solution A, use 0.50 g. For control solution B, use 0.50 g and 1.5 mL of nitrate ion (NO3) standard solution.
Calcium, Copper, Lead, Potassium, Sodium, and Zinc (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
For the Determination of Calcium, Copper, Lead, Potassium, Sodium, and Zinc
S a m p l e S t o c k S o l u t i o n A . Dissolve 20.0 g of sample with water in a 100 mL volumetric flask, and dilute to the mark with water (1 mL = 0.20 g). S a m p l e S t o c k S o l u t i o n B . Transfer 5.0 mL of sample stock solution A to a 100 mL volumetric flask, and dilute to the mark with water (1 mL = 0.01 g).
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4074 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
For the Determination of Calcium, Copper, Lead, Potassium, Sodium, and Zinc
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
Cu
324.7
4.0
0.04; 0.08
A/A
Yes
Pb
217.0
4.0
0.12; 0.24
A/A
Yes
K
766.5
0.40
0.02; 0.04
A/A
No
Na
589.0
0.05
0.005; 0.01
A/A
No
Zn
213.9
0.04
0.01; 0.02
A/A
Yes
*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)]. Dissolve 1.0 g in 30 mL of water, add 5 mL of hydrochloric acid, and dilute with water to 50 mL. Use this solution without further acidification.
© 2017 American Chemical Society
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DOI:10.1021/acsreagents.4074 ACS Reagent Chemicals, Part 4
