Monograph pubs.acs.org/doi/book/10.1021/acsreagents
Indigo Carmine (Acid Blue 74, C.I. 73015) 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 Indigo Carmine provides, in addition to common physical constants, a general description including typical appearance, applications, and aqueous solubility. The monograph also details the following specifications and corresponding tests for verifying that a substance meets ACS Reagent Grade specifications including: Clarity of Solution and Sensitivity to Nitrate.
C16H8N2Na2O8S2
Formula Wt 466.35
CAS No. 860-22-0
GENERAL DESCRIPTION Typical appearance . . . . . . . . . . . . . . . . . . . dark blue solid Applications . . . . . . . . . . . . . . . . . . . . . . . . reagent for detection of nitrate Aqueous solubility . . . . . . . . . . . . . . . . . . . . 1 g in 100 mL at 25 °C
SPECIFICATIONS Clarity of solution . . . . . . . . . . . . . . . . . . . . Passes test Sensitivity to nitrate . . . . . . . . . . . . . . . . . . Passes test
© 2017 American Chemical Society
A
DOI:10.1021/acsreagents.4173 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
TESTS Clarity of Solution Accurately weigh 1.0 g, and dissolve in 100 mL of water. The resulting solution should be clear, and no appreciable amount of insoluble residue should remain.
Sensitivity to Nitrate To 7 mL of water, add 5 mg of sodium chloride. Add 3.0 mL of nitrate ion (NO3) standard solution, and mix. Add 0.10 mL of 0.10% indigo carmine reagent solution (prepared using the sample) and 10 mL of sulfuric acid. The blue color should be completely discharged in 5 min.
© 2017 American Chemical Society
B
DOI:10.1021/acsreagents.4173 ACS Reagent Chemicals, Part 4
