Cadmium was quantitatively adsorbed from aqueous sample onto a microcolumn packed with cadion immobilized on sodium dodecyl sulfate-coated TiO2 nanoparticles. The retained cadmium was eluted with 2.5 mol L-1 hydrochloric acid solution and measured by cold vapor atomic absorption spectrometry (CVAAS). The influences of different variables such as pH, sample and eluent flow rates, amount of the sorbent and volume of the sample on the recovery of cadmium were investigated. Under the optimum conditions, a sample volume of 200 mL resulted in a preconcentration factor of 100. The precision (RSD%, n = 8) at the 0.05 µg L-1 level of cadmium was 3.6% and the limit of detection based on three times the standard deviation of blank solution (3Sb) was 1.3 ng L-1. The method was successfully applied to the determination of cadmium in rice, fish, milk, and water samples.
cadmium; solid phase extraction; cold vapor atomic absorption spectrometry; cadion; modified TiO2 nanoparticles
