1,2,4,6-Tetraphenylpyridinium perchlorate as a reagent for ion-association complex formation and its use for the spectrophotometric determination of thallium

Abstract

The synthesis, characteristics and applications of 1,2,4,6-tetraphenylpyridinium perchlorate (TPPP) as a reagent for the formation of ion-association complexes is described. This reagent forms a 1 : 1 complex with TlCl₄^–(λ_max. 310 nm, molar absorptivity 3.14 × 10⁴ l mol^–1 cm^–1) that is slightly soluble in water and can be extracted with isopentyl acetate with an extraction efficiency of 97.9%. The TlCl₄^–-TPP⁺ complex obtained is useful for the spectrophotometric determination of thallium in the concentration range 0.05–0.8 p.p.m., and the method is applicable to the determination of thallium in sphalerites and zinc concentrates.