SPADNS Nov 12, 2024 0 comment blog SPADNS SPADNS excellent quality manufacturer, exporter and supplier. SPADNS (4,5-Dihydroxy-3-(p-sulfophenylazo)-2,7-naphthalene disulfonic acid, trisodium salt) is indicator for zirconium, thorium and colorimetric indicator for fluoride. Code: RXSOL-69-2364-714 Other Equivalent Brand SPADNS Short Description: SPADNS Technical Specifications: Details