Technical Specification
Appearance : Grey to light purple or pink to yellow-tan crystals or powder
Solubility : 20 ppm in 50% ethanol yields clear solution
Visual pH Transition : pH 5.20 (yellow) - pH 6.80 (purple)
FTIR (KBr disc) : Matches with the standard pattern Absorption maxima (pH 5.2) : 426 - 436 nm (20 ppm in 50% ethanol) Absorption maxima (pH 6.8) : 584 - 594 nm (20 ppm in 50% ethanol) Absorptivity 1 : 400 - 450 (20 ppm in 50% ethanol, at 426 - 436 nm)
Absorptivity 2 : 1000 - 1100 (20 ppm in 50% ethanol, at 584 - 594 nm)
Loss on drying (at 110°C, 2hr) : <= 5.0%