Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Tin 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 Tin provides, in addition to common physical constants, a general description including typical appearance, applications, and change in state (approximate). The monograph also details the following specifications and corresponding tests for verifying that a substance meets ACS Reagent Grade specifications including: Assay, Antimony, Copper, Iron, Lead, and Arsenic.
Sn
Atomic Wt 118.71
CAS No. 7440-31-5
GENERAL DESCRIPTION Typical appearance . . . . . . . . . . . . . . . . . . . silver-white metal Applications . . . . . . . . . . . . . . . . . . . . . . . . reducing agent Change in state (approximate) . . . . . . . . . . . . melting point, 232 °C
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥99.5% Sn Maximum Allowable Antimony (Sb) . . . . . . . . . . . . . . . . . . . . . . 0.02% Copper (Cu) . . . . . . . . . . . . . . . . . . . . . . . . 0.005% Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.01% Lead (Pb) . . . . . . . . . . . . . . . . . . . . . . . . . 0.005% Arsenic (As) . . . . . . . . . . . . . . . . . . . . . . . . 1 ppm
© 2017 American Chemical Society
A
DOI:10.1021/acsreagents.4406 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
TESTS Assay (By complexometric titration). Weigh, to the nearest 0.1 mg, about 0.25 g of sample, and digest on a hot plate (~100 °C) in a covered beaker with 5 mL of hydrochloric acid until the sample is dissolved. Add 30.0 mL of 0.1 M EDTA volumetric solution, and heat the solution almost to boiling. Cool, and adjust the pH to 5.5, using a pH meter, with hexamethylenetetramine reagent solution. Dilute with water to about 150 mL, and add a few milligrams of xylenol orange indicator mixture. Titrate with 0.1 M lead nitrate volumetric solution to a change from yellow to reddish purple. One milliliter of 0.1 M EDTA corresponds to 0.01187 g of Sn.
Antimony, Copper, Iron, and Lead (By flame AAS, [Part 2: Trace and Ultratrace Elemental Analysis; Atomic Absorption Spectroscopy; Analysis; Procedure for Flame AAS]).
For the Determination of Antimony, Copper, Iron, and Lead
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 in 30 mL of hydrochloric acid and 3 mL of nitric acid by allowing to stand in a covered beaker until dissolution is complete. Transfer to a 100 mL volumetric flask, and dilute to the mark with water (1 mL = 0.10 g).
For the Determination of Antimony, Copper, Iron, and Lead
Element
Wavelength (nm)
Sample Wt (g)
Standard Added (mg)
Flame Type*
Background Correction
Sb
217.6
1.0
0.20; 0.40
A/A
Yes
Cu
324.8
0.50
0.025; 0.05
A/A
Yes
Fe
248.3
0.50
0.05; 0.10
A/A
Yes
Pb
217.0
1.0
0.05; 0.10
A/A
Yes
*A/A is air/acetylene.
Arsenic Dissolve 1.0 g in a mixture of 5 mL of water and 10 mL of nitric acid in a generator flask in a hood. Add 10 mL of dilute sulfuric acid (1:1), evaporate on a hot plate (~100 °C) to about 5 mL, and heat just to fumes of sulfur trioxide. (At this point, the metastannic acid should go into solution.) Cool, cautiously wash down the flask with 5–10 mL of water, and again heat just to fumes of sulfur trioxide. Cool, cautiously wash down the flask with 5–10 mL of water, and repeat the fuming. Cool, dilute with water to 55 mL, and proceed as described in the general method for arsenic in [Part 2: Colorimetry and Turbidimetry; Arsenic; Procedure for Arsenic], omitting the addition of the dilute sulfuric acid and using 2 mL of 48% hydrobromic acid instead of the potassium iodide solution specified in the procedure. Swirl the contents of the flask occasionally to break up the zinc mass. When evolution of gas stops, open the generator flask, and add 1 g portions of granulated zinc until the solution is clear and colorless. Any red color in the silver diethyldithiocarbamate solution of the sample should not exceed that in a standard containing 0.001 mg of arsenic ion (As).
© 2017 American Chemical Society
B
DOI:10.1021/acsreagents.4406 ACS Reagent Chemicals, Part 4
