Amaranth S

CI 16185; acid red 27; C₂₀H₁₁N₂Na₃O₁₀S₃ = 604 (915-67-3)

General reagent grade of commerce.

A deep brown or deep reddish brown, fine powder.

When used for the titration of iodine and iodides with potassium iodate, the colour changes from orange-red to yellow.