Hydroxy naphthol blue disodium, an azo dye, is a metal indicator for calcium and a colorimetric reagent for alkaline earth metal ions ( λmax = 650 nm). In the pH range between 12 and 13, the solution of the indicator is reddish pink in the presence of calcium ion and to deep blue in the presence of disodium EDTA^[1].

598.49

C₂₀H₁₂N₂Na₂O₁₁S₃

165660-27-5

羟基萘酚蓝二钠盐

Room temperature in continental US; may vary elsewhere.

Please store the product under the recommended conditions in the Certificate of Analysis.