Dispersive liquid-phase microextraction procedure for spectrometric determination of cadmium

A method has been developed for cadmium determination based on the formation of an ion associate between Cd(II) and 2-[2-(5-dimetylamino-2-tienyl)-vinyl]-1,3,3-trimetyl-3H-indolium bromide (DTVTI) reagent, with the aid of iodide as ligand, which is extractable by a mixture of toluene and tributylphosphate. The optimum experimental conditions were investigated and found to be as follows: pH 1.4, concentration of KI 0.02 mol L-1, concentration of DTVTI 1 x 10(-4) mol L-1, toluene as the extraction solvent and tributylphosphate as the donor-active solvent. The reaction mechanism and the role of the solvents were also discussed. The calibration plot was linear in the range of 0.11-2.25 mg L-1 of cadmium. The developed procedure was applied for cadmium determination in aqueous samples. (C) 2012 Elsevier B.V. All rights reserved.