indigo carmine
happe-aluse indikaator, mida kasutatakse tiitrimisel, a soluble blue dye C16H8N2Na2O8S2 that is a sodium salt, is used chiefly as a biological stain and food color, and since it is rapidly excreted by the kidneys is used as a dye to mark ureteral structures (as in cystoscopy and catheterization)
