A new method for solid-phase extraction and preconcentration of trace amounts of Cd(II) from environmental samples was developed by using sodium dodecyl sulphate-coated silica nanoparticles (SDS-coated SiO2 NPs) as a new sorbent [1]. The procedure is based on the adsorption of the analyte on the negatively charged surface of the SDS-coated SiO2 NPs and then elution of the preconcentration cadmium from the surface of the SDS-coated SiO2 NPs prior to its determination by flame atomic absorption spectrometry [1]. Various influencing parameters on the separation and preconcentration of trace amounts of cadmium, such as pH [1,2,3], amount of sorbent[2], sample volume [1,2,3], eluent type [1], concentration and volume of eluent [2,3], and extraction time [3], were studied. Under optimized conditions, calibration curve was linear in the range of between 5 and 100 ngmL-1.The relative standard deviation of the method was 3.5% (n=6). The proposed method has been validated using a certified reference materials, and also the method has been applied successfully for the determination of Cd(II) in aqueous samples.

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