Nanometer titanium dioxide immobilized on silica gel as sorbent for preconcentration of metal ions prior to their determination by inductively coupled plasma atomic emission spectrometry

Nanometer titanium dioxide immobilized on silica gel (immobilized nanometer TiO2) was prepared by sol–gel method and characterized by using X-ray diffraction (XRD) and scanning electron microscope (SEM). The adsorptive potential of immobilized nanometer TiO2 for the preconcentration of trace Cd, Cr, Cu and Mn was assessed in this work. The metal ions studied can be quantitative retained at a pH range of 8–9, and 0.5 mol L−1 HNO3 was sufficient for complete elution. The adsorption capacity of immobilized nanometer TiO2 for Cd, Cr, Cu and Mn was found to be 2.93, 2.11, 6.69 and 2.47 mg g−1, respectively. A new method using a microcolumn packed with immobilized nanometer TiO2 as sorbent has been developed for the preconcentration of trace amounts of Cd, Cr, Cu and Mn prior to their determination by inductively coupled plasma atomic emission spectrometry (ICP-AES). The method has been successfully applied for the determination of trace elements in some environmental samples with satisfactory results.