Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Devarda’s Alloy (Decarda Metal) 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 Devarda’s Alloy provides, in addition to common physical constants, a general description including typical appearance and applications. The monograph also details the following specifications and corresponding tests for verifying that a substance meets ACS Reagent Grade specifications including: Aluminum, Copper, Zinc and Nitrogen.
CAS No. 8049-11-4
GENERAL DESCRIPTION Typical appearance . . . . . . . . . . . . . . . . . . . gray solid Applications . . . . . . . . . . . . . . . . . . . . . . . . reducing agent for determination of nitrogen by Kjeldahl analysis
SPECIFICATIONS Aluminum (Al) (nominal) . . . . . . . . . . . . . . . . 44–46% Copper (Cu) (nominal) . . . . . . . . . . . . . . . . . 49–51% Zinc (Zn) (nominal) . . . . . . . . . . . . . . . . . . . 4–6% Maximum Allowable Nitrogen (N). . . . . . . . . . . . . . . . . . . . . . . . 0.005%
TESTS Aluminum, Copper, and Zinc (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
© 2017 American Chemical Society
A
DOI:10.1021/acsreagents.4113 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
For the Determination of Aluminum, Copper, and Zinc
S a m p l e S t o c k S o l u t i o n A . Weigh exactly 5.000 g, and in a fume hood, suspend in 25 mL of hydrochloric acid in a 1 L volumetric flask. After 1 h, add cautiously 25 mL of nitric acid in 5 mL increments. If a vigorous reaction with redbrown fumes takes place, immediately add 5–10 mL portions of water to quench the reaction. Once the alloy is in solution, cautiously add 500 mL of water, and cool. Dilute to the mark with water, and mix well (1 mL = 0.0050 g). S a m p l e S t o c k S o l u t i o n B . Pipette 50.0 mL of sample stock solution A into a 1 L volumetric flask, and dilute to volume with 1% hydrochloric acid solution (1 mL = 0.00025 g). S a m p l e S t o c k S o l u t i o n C . Pipette 50.0 mL of sample stock solution B to a 250 mL volumetric flask. Dilute to the mark with water, and mix well (1 mL = 0.00005 g).
Note: For aluminum determination, add 1.0 mL of 5% potassium chloride to the sample and standards. A reagent blank of equal amount of reagents is recommended.
For the Determination of Aluminum, Copper, and Zinc
Element
Wavelength (nm)
Sample Wt (g)
Standard Added (mg)
Flame Type*
Background Correction
Al
396.3
0.0005
0.15; 0.30
N/A
Yes
Cu
324.8
0.00005
0.015; 0.03
A/A
Yes
Zn
213.9
0.0005
0.015; 0.03
A/A
Yes
*A/A is air/acetylene; N/A is nitrous oxide/acetylene. Note: Compensate for any variation on the summation of the components that deviate from 100%.
Nitrogen Weigh accurately about 7.0 g of sample, and place in a Kjeldahl flask. Add slowly and cautiously 40 mL of hydrochloric acid with agitation. Cool, add 100 mL of 30% sodium hydroxide solution, and immediately connect to a Kjeldahl distillation apparatus, the tip of which is immersed in 10 mL of 0.02 N hydrochloric acid. Distill 75 mL into the 0.02 N hydrochloric acid solution, and titrate with 0.02 N sodium hydroxide solution to a methyl red end point. Not more than 0.9 mL of 0.02 N hydrochloric acid is consumed in excess of that used when a 2.0 g sample is treated in the same manner.
© 2017 American Chemical Society
B
DOI:10.1021/acsreagents.4113 ACS Reagent Chemicals, Part 4
