A Preconcentration Procedure Using 1-(2-Pyridylazo)-2-napthol Anchored to Silica Nanoparticle for the Analysis of Cadmium in Different Samples

A new analytical method using 1-(2-pyridylazo)-2-naphthol modified SiO2 nanoparticles as solid-phase extractant has been developed for the preconcentration of trace amounts of Cd(II) in different water samples. Conditions of the analysis such as preconcentration factor, effect of pH, sample volume, shaking time, elution conditions and effects of interfering ions for the recovery of analyte were investigated. The adsorption capacity of nanometer SiO2-PAN was found to be 60.57 mu mol/g at optimum pH and the detection limit (3 sigma) was 0.76 mu g/L. The extractant showed rapid kinetic sorption. The adsorption equilibrium of Cd(II) on nanometer SiO2-PAN was achieved just in 15 minutes. Adsorbed Cd(II) was easily eluted with 6 mL of 6 M hydrochloric acid. The maximum preconcentration factor was 50. The method was applied for the determination of trace amounts of Cd(II) in various synthetic samples and water samples.