Indigotin (indigo carmine) is a dye clinically used for diagnostic purposes. When it is intravenously administered, it causes dark blue discolouration of urine within 5-15 minutes of injection. This intense coloration enables the detection of any lesions of the urinary tract.

 Indigo Carmine can be produced by sulfonation of natural indigo, typically the indigo is also prepared synthetically by fusion of N-phenylglycine in a mixture of sodamide and sodium and potassium hydroxides under ammonia pressure. 

indigo-carmine method is a simple, rapid, accurate colorimetric procedure for determining small amounts of dissolved oxygen in water (0 to 50 ppm). A solution of reduced indigo-carmine dye added to a water sample is oxidized by the presence of any dissolved oxygen and changes color.

INDIGO CARMINE AR