Ultra-trace determination of thallium (I) in water using TiO2 nanoparticles prior to its quantitation by ICP-MS

Nowadays heavy metals such as thallium have received considerable attention owing to their effects in the pollution of the environment [1]. A new method has been developed for the determination of trace amounts of Tl(I) from aqueous solution based on simultaneous sorption and preconcentration with TiO2 nanoparticles as sorbent prior to its determination by Inductively coupled plasma mass spectrometry (ICP-MS). In this research we use self-made PTFE microcolumn packed with TiO2 nanoparticles with high specific surface area were prepared using sonochemical synthesis method at high frequency, low intensity and relatively low temperature (75˚C)[2]. The retained metal ions on the microcolumn were eluted with small amounts of a suitable eluent solvent. The optimum experimental parameters for preconcentration of Tl(I), such as pH, volume and flow rate of sample solution, eluent and interfering ions, have been investigated. Under the optimal conditions, the linear range, detection limit and precision (R.S.D., n=5) for Tl (I) were (35 -720 ng L−1 ), 5.0 ng L−1 and 2.3 % respectively. The adsorption capacity of TiO2 nanoparticles for Tl(I) was found to be 25 mg g−1. The method has been also applied for determination of trace of this element in some environmental water samples and standard reference material with satisfactory results.