Combination of Solid Phase Extraction With Dispersive Liquid-liquid Microextraction for Speciation of Thallium in Water Samples by Electrothermal Vaporization ICP-MS

Based on solid phase extraction (SPE) combined with dispersive liquid-liquid microextraction (DLLME), a novel method is described for speciation of thallium by electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS). In the SPE step, titanium dioxide nanofibers were used for precon-centration of the analytes and removal of the matrix by the selective adsorption. The elution solution from the SPE was employed for further preconcentration and separation of the analytes with DLLME. The main factors affecting SPE and DLLME were examined in detail. Under optimal conditions, the detection limit of this method for T1(III) was 0.039 pg mL(-1) with relative standard deviations of 6.5%. This technique exhibited a high enrichment factor of 400-fold. The concentration of T1(I) was calculated by subtracting T1(III) from total T1. Total T1 was determined as T1(III) after the oxidation of T1 into T1(III)- This method was applied for the determination of T1(I) and T1(III) in water samples (industrial wastewater, urban sewage, and lake water) with satisfactory results.