Extraction-spectrophotometric investigations on two ternary ion-association complexes of gallium(III)

Abstract

Complex formation and liquid-liquid extraction were studied in systems containing Ga(III), azoderivative of resorcinol {4-(2-pyridylazo) resorcinol (PAR) or 4-(2-thiazolylazo)resorcinol (TAR)}, 2,3,5-triphenyltetrazolium chloride (TTC), water and chloroform. The optimum conditions w.r.t. pH, extraction time, concentration of ADR and concentration of TTC for the extraction of Ga(III) as an ion-associate complex were found.. The composition of the extracted complexes, (TT +)[Ga(PAR) 2] (I), (TT +)[Ga(TAR) 2] (II) or (TT +) 2[Ga(OH) (TAR) 2] (III), and the constants of association (β) between 2,3,5-triphenyltetrazolium cation (TT +) with corresponding anionic chelates were established by several methods. The constants of distribution (K D) and extraction (K ex) of the principal species I and III were determined as well. The apparent molar absorptivities of the chloroform extract at the optimum extraction-spectrophotometric conditions were ε' 510=9.5×10 4 L mol -1 cm -1 (I) and ε' 530=4.6×10 4 L mol -1 cm -1 (III). The validity of Beer's law was checked and analytical characteristics that were calculated are reported herein. © Versita Sp. z o.o.