Synonyms: 3,4-Dihydroxy-9,10-dioxo-2-anthracenesulfonic acid sodium salt, Alizarin Carmine, Alizarin Red water soluble, Alizarin sodium monosulfonate, Alizarin sulfonate sodium, Alizarinsulfonic acid sodium salt, Sodium alizarinsulfonate, C.I. 58005 CAS: 130-22-3 Empirical Formula: C14H7NaO7S Molecular Weight: 342.26 g/mol Test Specification Description Yellow to orange to brown powder Identification (IR) Conforms to structure and standard Assay 70% min. Loss on Drying at 110 °C 6% max. Spectroscopy As per BSC Solubility (0.1% in H2O) Clear yellow solution Solubility (1.0g/L in H2O) 6 NTU Visual Transition Interval From pH 3.5 (yellow) to pH 6.5 (pink) and from pH 9.4 (orange-brown) to pH 12.0 (violet)