Monograph pubs.acs.org/doi/book/10.1021/acsreagents
2′,7′-Dichlorofluorescein (2′,7′-Dichloro-3′,6′-dihydroxyspiro[isobenzofuran-1(3H),9′-[9H]xanthen]-3-one; 2′,7′Dichloro-3,6-fluorandiol) 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 2′,7′-Dichlorofluorescein 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: Clarity of Alcohol Solution and Suitability as Adsorption Indicator.
C20H10Cl2O5
Formula Wt 401.20
CAS No. 76-54-0
GENERAL DESCRIPTION Typical appearance . . . . . . . . . . . . . . . . . . . orange to red-brown solid Applications . . . . . . . . . . . . . . . . . . . . . . . . argentimetric titration indicator
SPECIFICATIONS Clarity of alcohol solution . . . . . . . . . . . . . . . Passes test Suitability as absorption indicator . . . . . . . . . . Passes test
© 2017 American Chemical Society
A
DOI:10.1021/acsreagents.4115 ACS Reagent Chemicals, Part 4
ACS Reagent Chemicals
Monograph
pubs.acs.org/doi/book/10.1021/acsreagents
TESTS Clarity of Alcohol Solution Dissolve 100 mg in 100 mL of 70% alcohol. The solution should be clear and greenish yellow. Reserve the solution for the test for suitability as absorption indicator.
Suitability as Adsorption Indicator Prepare a 0.10 M solution of sodium chloride by dissolving 0.58 g of sodium chloride in water, and diluting with water to 100.0 mL. Dilute 10.0 mL of the 0.10 M sodium chloride with 30 mL of water, add 0.5 mL of the solution reserved from the preceding test, and titrate with 0.10 N silver nitrate, protecting the titration vessel from direct sunlight. The color change from greenish yellow to rose should require between 9.9 and 10.1 mL of 0.10 N silver nitrate.
© 2017 American Chemical Society
B
DOI:10.1021/acsreagents.4115 ACS Reagent Chemicals, Part 4
