Dye content (spectrophotometrically; calc. on dried substance): ≥ 90.0%

Identity (UV/VIS-Spectrum): passes test

Absorbance characteristics (Ratio,E (λmax - 15 nm)/E (λmax +  15 nm)): 0.98 - 1.20

Absorption maximum λmax. (water): 589 - 594 nm

Spec. Absorptivity A 1%/1cm (λmax; 0.002 g/l; water): 2000 - 2450

TLC-Test: passes test

Michler`s ketone: <0.10%

Loss on drying (110 °C, 4 h): ≤ 7.5%

Suitability as indicator (ACS): passes test

Suitability as indicator (Reag. Ph. Eur.): passes test