Appearance: Black crystals with metallic lusterPurity (HPLC):≥94%Solubility:Deep yellow to black solution (2.5% in 1N NaOH)Water (Karl Fisher):≤3.0%Potassium (IC):≤2%Infrared Spectrum:Conforms to structureUV Wavelength λmax:385 ± 2 nm (0.009mg/ml in 0.1N NaOH)Storage Temp: Store at 0-8°C