Heavy metals determination in water and food samples after preconcentration by a new nanoporous adsorbent.

In this work, SBA-15 mesoporous silica has been chemically functionalized with guanidin groups. The resulting material has been characterised and employed as solid phase extractant for preconcentration of Pb2+, Cu2+, Zn2+ and Cd2+ ions. The ions were identified by flame atomic absorption spectrometry (FAAS). The enrichment factor of the proposed method was 100 and detection limits were found to be 4.5, 0.6, 0.2 and 0.5 ng mL(-1) for Pb2+, Cu2+, Zn2+ and Cd2+ respectively. The time and the optimum amount of the sorbent, pH and minimum amount of acid for stripping and break through volume were investigated. The maximum capacity the adsorbent was found to be 89.1 (+/- 1.7) mu g, 57.2 (+/- 1.6) mu g 26.8 (+/- 1.6) mu g and 36.0 (+/- 0.6) mu g of Pb2+, Cu2+, Zn2+ and Cd2+ per mg functionalized SBA-15, respectively. Guanidin functionalized SBA-15 was successfully applied as a new solid extractant for the simultaneous preconcentration of Pb2+, Cu2+, Zn2+ and Cd2+ ions in water and food samples. (C) 2013 Elsevier Ltd. All rights reserved.