Simultaneous separation and determination of trace amounts of Cd(II) and Cu(II) in environmental samples using novel diphenylcarbazide modified nanoporous silica

A novel sorbent for simultaneous separation of cadmium and copper was prepared by functionalizing SBA-15 nanoporous silica with diphenylcarbazide. A solid-phase extraction method using the above sorbent has been developed to separate and concentrate trace amount of cadmium and copper ions from environmental samples by flame atomic absorption spectrophotometry measurements. The optimum experimental conditions such as pH, flow rates, type and the smallest amount of eluent for elution of cadmium and copper ions, break through volume and effect of coexisting ions on the separation and determination of cadmium and copper ions were evaluated. The extraction efficiency for cadmium and copper ions were greater than 98% and limit of detection (LOD) was 0.15 and 0.45 ng mL(-1) for cadmium and copper, respectively. The preconcentration factor was 294 and 291 for cadmium and copper, respectively, and the relative standard deviation (RSD) of the method was <4% for 10 separate column experiments for the determination of 5.0 mu g cadmium and copper ions. The adsorption capacity of the nanoporous silica was 198 mg g(-1) for cadmium and 105 mg g(-1) for copper on functionalized SBA-15 nanoporous silica. Validation of the outlined method was performed by analyzing certified reference materials (Soil (NCS DC 73323) and ore polymetallic gold Zidarovo-PMZrZ (206 BG 326)). The practical applicability of the developed sorbent was examined using real samples such as sea water, fish and sediment samples. (C) 2011 Elsevier B.V. All rights reserved.