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 × 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.