Indigo Carmine ACS/USP C.I. 73015

Indigo Carmine is a dark blue to purple powder. The primary use is as a pH indicator. It is blue at pH 11.4 and yellow at 13.0. Indigo carmine is also a redox indicator, turning yellow upon reduction.

C.I.73015
Minimum Assay: >80%
Molecular Formula C16H8N2Na2O8S2
Molecular Weight 466.36 g/mol
Loss on drying:  5.0% maximum
Visual Transition Interval:             From pH 11.5 (Blue) To pH 14.0 (yellow)
Aqueous solubility: 1 g in 100 ml at 25 Deg. C
Subsidiary dyes, excluding disodium
3,3-dioxo 2,2’-bi-indolylidine-5,7’-disulfonate:   1.00% maximum
Dye intermediates: < 0.50%
Lead:     <0.001%
Sulphur:   13.0 – 14.0%

Cas Number: 860-22-0

Einecs Number: 212-728-8

HS Code / Commodity Code: 32129000

Hazard Phrases: H302