Nanometer-sized alumina coated with chromotropic acid as solid phase metal extractant from environmental samples and determination by inductively coupled plasma atomic emission spectrometry

A method for solid phase extraction of trace metals such as Cd2+, Cr6+, Cu2+, Fe3+, Mn2+, Ni2+, Pb2+ and Zn2+ using nanometer-sized alumina coated with chromotropic acid prior to determination by inductively coupled plasma atomic emission spectrometry (ICP-AES) has been developed. Various influencing parameters on the separation and preconcentration of trace metals, pH, flow rate, sample volume, amount of adsorbent, concentration of eluent and sorption kinetics have been studied. The detection limits for Cd2+, Cr6+, Cu2+, Fe3+, Mn2+, Ni2+, Pb2+ and Zn2+ were found to be 0.14, 0.62, 0.22, 0.54, 0.27, 0.28, 0.53 and 0.38 ng ml− 1, respectively. The adsorption capacity of the solid phase adsorption material is 10.3, 11.3, 14.5, 16.4, 15.1, 11.7, 15.4 and 16.8 mg g− 1 for Cd2+, Cr6+, Cu2+, Fe3+, Mn2+, Ni2+, Pb2+ and Zn2+, respectively. The preconcentration factor was obtained in the range of 50–100 for all studied metal ions. Coexisting ions over a high concentration range have not shown any significant effects on the determination of aforesaid metal ions. The accuracy of the proposed method was tested by standard reference materials (NIST 1643e: water, NIST 1573a: tomato leaves and NIST 1568a rice flour) and natural waters and the results obtained were in good agreement with the certified values.