Specification Product Name BROMO CRESOL PURPLE Synonyms 5',5"-Dibromo-o-cresolsulfonephthalein CAS NO. 115-40-2 Molecular Formula C21H16Br2O5S Molecular Weight 540.24 Appearance Grey to light purple or pink to yellow-tan powder Structure     Tests    Limits 1. Transition Range pH 5.2 – pH 6.8 Greenish Yellow – Purple 2. Solubility 0.1% (EtOH) Clear golden yellow Solution 3. Absorptivity 1%/1cm, (pH 5.2) at λ max.431.0nm (pH 6.8) at λ max.589.0nm 400-450 1000-1100 4. Loss on Drying at 1100C (1hr) < 1%         REVISED: 1-1-2012