Assay (HPLC): ≥ 98.0%.
Appearance: White to off-white crystalline powder.
Identification (UV): Fluoresces blue under UV light.
Melting Range: 204-206°C.
Loss on Drying: ≤ 0.5% (at 105°C for 2 hours).
Residue on Ignition: ≤ 0.1%.
Heavy Metals (as Pb): ≤ 10 ppm.
Related Substances (HPLC): Total impurities ≤ 1.0%.
Aesculetin: ≤ 0.2%.
Solubility: Soluble in hot water, sparingly soluble in cold water.
Fluorescence: Strong blue fluorescence in alkaline solution.
pH (saturated solution): 5.0-7.0.
Purity (HPLC): ≥ 98.0% by area.