Extraction-Chromogenic Systems for Vanadium(V) Based on Azo Dyes and Xylometazoline Hydrochloride

Liquid-liquid extraction-chromogenic systems for vanadium(V) based on xylometazoline hydrochloride (XMZ) and azo derivatives of resorcinol (ADRs) were studied. The following ADRs were used: 4-(2-thiazolylazo)resorcinol (TAR), 5-methyl-4-(2-thiazolylazo)resorcinol (MTAR), and 6-hexyl-4-(2-thiazolylazo)resorcinol (HTAR). Concentration of the reagents, pH of the aqueous medium and shaking time were subjects of optimization experiments. The chloroform-extracted ternary complexes were of composition 1:1:1. The molar absorptivity coefficients (el), absorption maxima (l), constants of extraction (Log K), and fractions extracted (E%) were found to be e553 = 2.50 ´ 104 dm3 mol-1 cm-1, Log K = 3.5, and E = 96% (ADR = TAR); e550 = 1.88 ´ 104 dm3 mol-1 cm-1, Log K = 3.4, and E = 98% (ADR = MTAR); and e554 = 2.62 ´ 104 dm3 mol-1 cm-1, Log K = 5.0, and E = 99.5% (ADR = HTAR). The Sandell's sensitivities and Beer's law limits were determined as well.