Extraction-spectrophotometric determination of gallium with 1,2,4,6-tetraphenylpyridinium perchlorate

Abstract

The characteristics and applications of 1,2,4,6-tetraphenylpyridinium perchlorate (TPPP) as a reagent for the spectrophotometric determination of gallium are described. This reagent forms a 1 : 1 complex with GaCl₄-(λ_max. 310 nm, molar absorptivity 2.91 × 10⁴ l mol^–1 cm^–1) that is slightly soluble in water and can be extracted with isopentyl acetate with an extraction efficiency of 97.4%. The TPP⁺ GaCl₄^– complex obtained is useful for the spectrophotometric determination of gallium in the concentration range 0.1–2.2 µg ml^–1 in the organic phase, and the method is applicable to the determination of gallium in aluminium.