Monograph pubs.acs.org/doi/book/10.1021/acsreagents
4-Amino-3-hydroxy-1-naphthalene Sulfonic Acid (1-Amino-2-naphthol-4-sulfonic Acid)
Downloaded by CORNELL UNIV on May 15, 2017 | http://pubs.acs.org Publication Date (Web): February 28, 2017 | doi: 10.1021/acsreagents.4015
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 4-Amino-3-hydroxy-1-naphthalene Sulfonic Acid 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, Solubility in Sodium Carbonate, Residue after Ignition, Sulfate, and Sensitivity to Phosphate.
H2N(HO)C10H5SO3H
Formula Wt 239.25
CAS No. 116-63-2
GENERAL DESCRIPTION Typical appearance . . . . . . . . Applications . . . . . . . . . . . . . Change in state (approximate) . Aqueous solubility . . . . . . . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
. . . .
white to slightly brownish-pink powder determination of phosphate melting point, 285 °C insoluble
SPECIFICATIONS Assay . . . . . . . . . . . . . . . . . . . . . . . . . . . . ≥90.0% H2N(HO)C10H5SO3H Maximum Allowable Solubility in sodium carbonate . . . . . . . . . . . . Passes test Residue after ignition. . . . . . . . . . . . . . . . . . 0.1% Sulfate (SO4) . . . . . . . . . . . . . . . . . . . . . . . 0.2% Sensitivity to phosphate . . . . . . . . . . . . . . . . Passes test
© 2017 American Chemical Society
A
ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4015 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
TESTS Assay (By acid–base titrimetry). Weigh accurately about 0.5 g and transfer to a beaker. Add 100 mL of dimethyl sulfoxide, and while stirring, add 25 mL of water in small portions. Insert the electrodes of a suitable pH meter, and titrate with 0.1 N sodium hydroxide, establishing the end point potentiometrically. Correct for a blank determination. One milliliter of 0.1 N sodium hydroxide corresponds to 0.02392 g of H2N(HO)C10H5SO3H.
Downloaded by CORNELL UNIV on May 15, 2017 | http://pubs.acs.org Publication Date (Web): February 28, 2017 | doi: 10.1021/acsreagents.4015
Solubility in Sodium Carbonate Dissolve 0.1 g in 3 mL of 1% sodium carbonate reagent solution, and dilute with water to 10 mL. The solution should be clear and dissolution complete, or nearly so.
Residue after Ignition [Part 2: Gravimetric Methods; Residue after Ignition]. Ignite 1.0 g.
Sulfate Transfer 0.5 g to a beaker, add 25 mL of water and 0.10 mL of hydrochloric acid, and heat on a hot plate (~100 °C) for 10 min. Cool, dilute with water to 50 mL, and filter. To 10 mL of the clear filtrate, add 1 mL of 1 N hydrochloric acid and 2 mL of 12% barium chloride reagent solution. Any turbidity should not exceed that produced by 0.2 mg of sulfate ion (SO4) in an equal volume of solution containing the quantities of reagents used in the test. Compare 10 min after adding the barium chloride to the sample and standard solutions.
Sensitivity to Phosphate Dissolve 0.10 g in a mixture of 50 mL of water and 10 g of sodium bisulfite, warm if necessary to complete dissolution, and filter. Add 1.0 mL of this solution to a test solution prepared as follows: To 20 mL of water, add 0.02 mg of phosphate ion (PO4) and 2 mL of 25% sulfuric acid reagent solution, mix, and then add 1.0 mL of ammonium molybdate reagent solution. A distinct blue color should be produced in the test solution in 5 min.
© 2017 American Chemical Society
B
ACS Reagent Chemicals ACS Reagent Chemicals; American Chemical Society: Washington, DC, 2017.
DOI:10.1021/acsreagents.4015 ACS Reagent Chemicals, Part 4
