Formula: C₁₈H₁₈N₄O₆ CAS: 582-17-2 EC No.: 209-480-3 M (Molar Mass): 386.36 g/mol Full Name: 2-(4-Hydroxyphenylazo)benzoic acid Use: Chromogenic substrate for avidin-biotin assays

Assay (HPLC): ≥ 98.0% Appearance: Orange to red crystalline powder Identification (UV): λmax 348 nm (pH 7.4), 500 nm (pH 10) Extinction Coefficient: ε₅₀₀ = 34,000 M⁻¹cm⁻¹ at pH 10 Loss on Drying: ≤ 0.5% Sulfated Ash: ≤ 0.1% Heavy Metals (as Pb): ≤ 20 ppm Avidin Binding: Displaced by biotin (color change) Solubility: Soluble in alkaline solutions pH (saturated solution): 5.0-7.0