Identity (UV/VIS-Spectrum): passes test

Appearance: Red to red-violet powder, eventually with granular parts.

Clarity of solution (1 g/l; ethanol): passes test

Melting point (capillary method, temperatur measerment in the heating block): 179 - 182 °C

Transition range: pH 4.4 - pH 6.0 Red - yellow

Absorption maximum (buffer pH 4.5): 523 - 526 nm

Absorption maximum (buffer pH 6.2): 427 - 437 nm

Spec. Absorptivity A 1%/1cm (λmax; 0.005 g/l; buffer pH 4.5; calculated on anhydrous substance): 1350 - 1500

Spec. Absorptivity A 1%/1cm (λmax; 0.005 g/l; buffer pH 6.2; calculated on anhydrous substance): 700 - 800

Transition range (according to ACS): passes test

Loss on drying (110 °C): ≤ 5 %