Extraction-Chromogenic System for Nickel(II) Based on 5-methyl-4-(2-thiazolylazo)resorcinol and Aliquat 336

Abstract

A water−isobutanol extraction-chromogenic system for Ni II , based on the azo dye 5-methyl-4-(2-thiazolylazo)resorcinol (MTAR; H 2 L) and the ionic liquid Aliquat 336 (A336), was studied. Under the optimal conditions (c MTAR = 2.0 × 10-4 mol dm-3 , c A336 = 5.6 × 10-3 mol dm-3 , pH 8.5 and extraction time t = 1 min), Ni II is extracted as a ternary complex which can be represented by the formula (A336 +) 2 [Ni(L 2−) 2 ]. In the absence of A336, or in a slightly acidic medium, a binary complex, [Ni(HL −) 2 ], with an absorption maximum at λ = 548 nm and a shoulder at 590 nm is formed. The following extraction-spectrophotometric characteristics were determined at the above-mentioned optimal conditions: λ max (545 nm), molar absorptivity (5.0 × 10 4 dm 3 mol-1 cm-1), Sandell's sensitivity (1.2 × 10-3 μg cm-2), Beer's law limits (0.05-3.1 µg cm-3), constant of extraction (Log K = 6.1) and fraction extracted (99.2%). The effect of foreign ions was studied; the most serious interferences were caused by Co II , Cu II and Cr III .

Extraction-Chromogenic System for Cobalt Based on 5-Methyl-4-(2-thiazolylazo) Resorcinol and Benzalkonium Chloride

“…16,18,20,[34][35][36] 5-Methyl-4-(2-thiazolylazo)resorcinol (MTAR) 37 is a TAR derivative that has been used in our laboratory for the liquid-liquid extraction of V IV,V [38][39][40][41][42] and Ni II . 43 Its interaction with Co II in water-ethanol medium has been studied by Kiryukhina. 44 This reagent has also been used for the reversed-phase capillary high-performance liquid chromatographic determination of Co II .…”

Study on the Equilibria of the Complex Formation of Anionic Chelate of Zn(II) with Tridentate Ligand and the Cation of 3-(2-naphtyl)-2,5-diphenyl-2H-tetrazolium chloride

“…The selected organic solvent i-BuOH is characterized by a low volatility and toxicity, it is readily biodegradable and non-bioaccumulative, and can be produced from renewable resources. 50,51 The final goal was to evaluate the possible applications of the system for the determination of the traces of zinc(II) in biological, medical, and pharmaceutical samples.…”