Extraction-Chromogenic Systems for Gallium(III) Based on Azo Dyes and Xylometazoline Hydrochloride

摘要

Two liquid-liquid extraction-chromogenic systems for Ga(III)based on azo dyes (ADs) and xylometazoline hydrochloride (XMH) have been studied. The ADs used were 4-(2-pyridylazo)resorcinol (PAR) and 4-(2-thiazolylazo)resorcinol (TAR). The optimum conditions (pH, AD concentration, XMH concentration, and extraction time) for the formation of ternary complexes of general formula (XMH+)[Ga-III(AD(2-))(2)], that are readily extracted into chloroform, have been worked out. The following extraction-spectrophotometric characteristics: absorption maxima (lambda), molar absorptivities (epsilon(lambda)), limits of detection (LOD), limits of quantitation (LOQ), constants of extraction (K-ex), and fractions extracted (E) have been determined. The system in which AD = PAR has better performance: epsilon(512)= 9.9x10(4)dm(3)mol(-1)cm(-1), LOD = 2.8 ng/cm(3), LOQ = 9.4 ng/cm(3), logK(ex)= 4.1, andE= 97%. Extraction equilibrium with this reagent is achieved in a short time (only a few seconds) and the optimum pH interval is broad (5.1-7.8).