Synonyms: C.I. 73015 CAS: 860-22-0 Empirical Formula: C16H8N2Na2O8S2 Molecular Weight: 466.35 g/mol Test Specification Description Dark blue to purple powder Dye content (dried basis) 80% min. Loss on drying 5.0% max. Visual Transition Interval From pH 11.5 (blue) to pH 14.0 (yellow) Aqueous solubility 1g in 100ml at 25 Deg. C Subsidiary dyes, excluding disodium 3,3-dioxo 2,2-bi-indolylidine-5,7 disulfonate 1.0% max. Dye Intermediates 0.5% max. Arsenic 8 ppm max. Lead 0.001% max. Sulfur 13.0 - 14.0% Mercury 1 ppm max. Cadmium 1 ppm max. Heavy metals (as Pb) 40 ppm max.