Extraction of Gallium(III) with a New Azo Dye in The Presence or Absence of Xylometazoline Hydrochloride

Complex formation between Ga(III) and 6-hexyl-4-(2-thiazolylazo)resorcinol (HTAR, H2L) was studied in a water-chloroform medium, in the presence or absence of xylometazoline hydrochloride (XMH). Optimum conditions for the extraction of Ga(III) were found. In the presence of XMH, the extracted ion-associate has the formula (XMH+)[GaIIIL2], where HTAR is in its deprotonated form L2–. Some key extraction-spectrophotometric characteristics were determined: absorption maximum (521 nm), apparent molar absorptivity (5.8 × 104 dm3 mol–1 cm–1), limit of detection (18 ng cm–3), limit of quantitation (60 ng cm–3), extraction constant (LogK = 4.44), distribution ratio (LogD = 2.2) and fraction extracted (99.3 %). In the absence of XMH, the extracted chelate contains one deprotonated and one monoprotonated HTAR: [GaIII(HL–)(L2–)]. It has an absorption maximum at 523 nm and a shoulder at 580–590 nm. The pKa of HTAR (H2L ⇄ H+ + HL– equilibrium) was calculated (5.4) and the effect of foreign ions was studied. This work is licensed under a Creative Commons Attribution 4.0 International License.