Abstract

Kiril B. Gavazov*, Galya K. Toncheva, Teodora S. Stefanova and Kiril K. Simitchiev

DOI : http://dx.doi.org/10.13005/ojc/310244

Liquid-liquid extraction systems containing Fe^III, 4-(2-thiazolylazo)resorcinol (TAR), and a ditetrazolium salt (DTS: Neotetrazoliumchlortide, Blue Tetrazolium chloride, or Nitro Blue Tetrazolium chloride), water and chloroform were investigated. The optimum conditions for iron extraction, some equilibrium constants (association constants, distribution constants, and extraction constants), and characteristics (molar absorptivities, Sandell’s sensitivities, limits of detection and quantification) were found. The extracted species are ternary complexes with a general formula of (DT²⁺)[Fe^II(TAR)₂]. In this formula the metal ion is in oxidation state II, the azo dye is in doubly deprotonated form (TAR²⁻), and the ditetrazoliumcation (DT) has a charge of 2+.

iron(III); azo dye; bis(tetrazolium) salt; liquid-liquid extraction; ternary complex

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