Preconcentration of trace cadmium and manganese using 1-(2-pyridylazo)-2-naphthol-modified TiO2 nanoparticles and their determination by flame atomic absorption spectrometry

A new method has been developed for the preconcentration of trace amounts of manganese and cadmium prior to their determination by flame atomic absorption spectrometry (FAAS). The method is based on using a microcolumn packed with 1-(2-pyridylazo)-2-naphthol (PAN)-modified sodium dodecyl sulfate (SDS) coated TiO2 nanoparticles as a solid-phase sorbent. Effects of pH, sample flow rate and volume, elution solution and interfering ions on the recovery of the analytes have been investigated. The adsorption capacity of modified TiO2 nanoparticles was found to be 9.2 and 8.9 mg g-1 for Mn and Cd, respectively. The detection limits (3 sigma) of this method are 1.0 and 0.96 ng mL-1 for Mn and Cd, respectively. The proposed method has been applied to the determination of the elements in water samples with satisfactory results.