Chemically modified carbon nanotubes as efficient and selective sorbent for enrichment of trace amount of some metal ions

Multi-walled carbon nanotubes (MWCNT) was oxidized and chemically functionalized by 3-hydroxy-4-((3-silylpropylimino) methyl) phenol (HSPIMP) and characterized with FT-IR technique. This new sorbent was used for enrichment and preconcentration of Cu2+, Ni2+, Zn2+, Pb2+, Co2+, Fe3+ ions. Variables such as pH, amount of solid phase, eluting solution conditions (type, volume and concentrations) have significant effect on sorption and recoveries of analytes and the influence was optimized. At optimum value of conditions, the interference of other ions on understudy ions recoveries was investigated. The metal ions loaded on the solid phase via chelation with the new sorbent and subsequently efficiently eluted using 6 mL of 4 mol L−1 HNO3 solution. At each run, metal ions content was determined by flame atomic absorption spectrometry (FAAS). Relative standard deviation (N = 3) for determination of 0.2 μg mL−1 of analytes was between 1.6 and 3.0%, while their detection limit was between 1.0 and 2.6 ng mL−1 (3Sb, n = 10). The sorption capacity of HSPIMP–MWCNT for understudy ions was above 30 mg g−1. The proposed method successfully applied for the extraction and determination of the understudy metal ions in different samples.