Reaction of antimony(III) with tris[2,4,6-(2-hydroxy-4-sulpho-1-naphthylazo)]-s-triazine trisodium salt as a spectrophotometric method for the determination of sulphide

Abstract

Antimony(III) interacts with tris[2,4,6-(2-hydroxy-4-sulpho-1-naphthylazo)]-s-triazine trisodium salt (THT) to give a 1 : 1 dark red complex at pH 3.3–7.0. Sandell's sensitivity of the colour reaction at λ_max. 535 nm is 0.0029 µg cm^–2 of Sb (ε= 4.16 × 10⁴ l mol^–1 cm^–1). Among the anions, sulphide only decomposes the antimony-THT complex quantitatively replacing THT from the complex and 6–52 µg per 25 ml of sulphide are determined indirectly.