Study on Solid-phase Extraction and Flame Atomic Absorption Spectrometry for the Selective Determination of Cadmium in Water and Plant Samples with Modified Clinoptilolite

A sensitive, simple separation and solid-phase procedure, which is sorption and desorption of cadmium on modified clinoptilolite zeolite (with surfactant and neothorine), for preconcentration of cadmium prior to analysis by FAAS is described. The sorbent has exhibited good sorption potential for cadmium at pH 5. Cadmium was eluted from the column by nitric acid which resulted in preconcentration factor of 160. Thermodynamic behaviors for the process are investigated and adsorption process is interpreted in term of Freundlich equation. A detection limit of 0.015 ng mL(-1) was obtained and it is shown that calibration curve is linear from 0.01 to 4.0 microg mL(-1) in the final solution. Furthermore, the effects of various parameters such as pH, flow rate of the sample and eluent solution were studied. This method was successfully applied for determination of cadmium in various plant and real water samples.