a. Chem. [SULPH-.] Sulphindigotic acid: an acid formed by the action of sulphuric acid on indigo. Hence Sulphindigotate, a salt of sulphindigotic acid. (Also SULPHO-INDIGOTIC, -ATE.)
1857. Miller, Elem. Chem., Org., viii. 530. Sulphuric acid appears to form several compounds with indigo; two of them have been analysed, viz., the sulphindylic, or sulphindigotic acid, and the sulphopurpuric.
1876. trans. Schützenberger’s Ferment., 110. Sodium sulphindigotate.
1896. Allbutt’s Syst. Med., I. 514. Formate and sulphindigotate of sodium.
