Development of phosphate-containing polymer-based solid phase extraction procedure for the separation, enrichment, and determination of cadmium in water and food samples by FAAS

Abstract

A phosphorous-containing polymer (PhCP) has been used as an adsorbent for solid phase extraction (SPE) of cadmium at ultratrace levels. Cd2+ in aqueous solution was combined with 8-hydroquinoline and adsorbed on the PhCP column, then the desorption step was carried out with 3 mL of 3M HNO3. Several analytical factors affecting the adsorption and enrichment efficiency of trace levels of cadmium include the pH of the solution, 8-hydroquinoline concentration, concentration of the eluent, and sample volume which were optimized to obtain good selectivity and quantitative extraction yield. The adsorption capacity of the PhCP sorbent was 9.0 mg/g, the limit of detection (LOD) 0.41 μg/L with a preconcentration factor of 20. The relative standard deviation of 25 μg/L Cd was 4.23%. The presented procedure was validated by the analysis of certified reference materials and the standard addition method. The analytical results showed good agreement with the certified values and the recoveries were in the range of 97-100%. The method was successfully applied for the enrichment and determination of cadmium in water and food samples and analysis by FAAS.