Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Ammonium Hydroxide (Aqueous Ammonia)
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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 Ammonium Hydroxide 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: Appearance, Assay, Residue after Ignition, Carbon Dioxide, Chloride, Nitrate, Phosphate, Sulfate, Heavy Metals, Iron, and Substances Reducing Permanganate.
NH4OH
Formula Wt 35.05
CAS No. 1336-21-6
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
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clear liquid with a suffocating odor buffers; pH adjustment boiling point, 100 °C soluble
SPECIFICATIONS Appearance . . . . . . . . . . . . . . . . . . . . . . . . Passes test Assay (as NH3) . . . . . . . . . . . . . . . . . . . . . . 28.0–30.0% Maximum Allowable Residue after ignition. . . . . . . . . . . . . . . . . . 0.002% Carbon dioxide (CO2) . . . . . . . . . . . . . . . . . . 0.002% Chloride (Cl) . . . . . . . . . . . . . . . . . . . . . . . 0.5 ppm Nitrate (NO3) . . . . . . . . . . . . . . . . . . . . . . . 2 ppm Phosphate (PO4) . . . . . . . . . . . . . . . . . . . . . 2 ppm Sulfate (SO4) . . . . . . . . . . . . . . . . . . . . . . . 2 ppm Heavy metals (as Pb) . . . . . . . . . . . . . . . . . . 0.5 ppm
© 2017 American Chemical Society
A
ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4024 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Iron (Fe) . . . . . . . . . . . . . . . . . . . . . . . . . . 0.2 ppm Substances reducing permanganate . . . . . . . . . Passes test
TESTS Appearance Mix the material in the original container, pour 10 mL into a test tube (20 mm × 150 mm), and compare with distilled water in a similar tube. The liquids should be equally clear and free from suspended matter; looking across the columns by means of transmitted light should reveal no apparent difference in color between the two liquids.
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Assay (By acidimetry). Tare a small glass-stoppered Erlenmeyer flask containing 35 mL of water. Using a measuring pipette, without suction, introduce barely under the surface about 2 mL of the ammonium hydroxide, stopper, and weigh accurately. Titrate with 1 N hydrochloric acid, using methyl red indicator solution. One milliliter of 1 N hydrochloric acid is equivalent to 0.01703 g of NH3.
Residue after Ignition [Part 2: Gravimetric Methods; Residue after Ignition]. Evaporate 50 g (56 mL) and ignite.
Carbon Dioxide Dilute 10.0 g (11 mL) of the sample with 10 mL of water free from carbon dioxide, and add 5 mL of clear saturated barium hydroxide solution. Any turbidity should not be greater than is produced when the same quantity of barium hydroxide solution is added to 21 mL of carbon dioxide-free water containing 0.3 mg of carbonate standard (0.2 mg of carbon dioxide).
Chloride, Nitrate, Phosphate, and Sulfate (By ion chromatography, [Part 2: Chromatography; Recommended Procedures; Ion Chromatography]). Add 2 mL of 1% sodium carbonate reagent solution to 10 g (11 mL) of sample, and evaporate to dryness. Prepare also a blank and a standard with 0.005 mg chloride and 0.02 mg each of nitrate, phosphate, and sulfate. Take up in water, and dilute each to 10 mL in a volumetric flask. Analyze 50 µL aliquots by ion chromatography, and measure the various peaks. The differences between the sample and the blank should not be greater than the corresponding differences between the standard and the sample.
Heavy Metals [Part 2: Colorimetry and Turbidimetry; Heavy Metals (as Lead); Procedure for Heavy Metals, Method 1]. To 40.0 g (44 mL), add 10 mL of 1% sodium carbonate reagent solution, evaporate to dryness on a hot plate (~100 °C), dissolve the residue in about 20 mL of water, and dilute with water to 25 mL.
Iron [Part 2: Colorimetry and Turbidimetry; Iron; Procedure for Iron, Method 1 (Ammonium Thiocyanate)]. To 50 g (56 mL), add about 10 mg of sodium carbonate, and evaporate to dryness on a hot plate (~100 °C). Dissolve the residue in 3 mL of hydrochloric acid, dilute with water to 50 mL, and use this solution without further acidification.
© 2017 American Chemical Society
B
ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4024 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
Substances Reducing Permanganate
Downloaded by CORNELL UNIV on May 19, 2017 | http://pubs.acs.org Publication Date (Web): February 28, 2017 | doi: 10.1021/acsreagents.4024
Dilute 3 mL of the sample with 5 mL of water, and add 50 mL of 10% sulfuric acid reagent solution. Add 0.05 mL of 0.1 N potassium permanganate, heat to boiling, and keep at this temperature for 5 min. The pink color should not be entirely discharged.
© 2017 American Chemical Society
C
ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4024 ACS Reagent Chemicals, Part 4
