Chemically bonded multiwalled carbon nanotubes as efficient material for solid phase extraction of some metal ions in food samples

Abstract

Multiwalled carbon nanotubes chemically functionalized with 2-((3-silylpropylimino) methyl) phenol (SPIMP-MWCNT) and successfully applied for the solid phase extraction (SPE) of some metal ions in food samples. The influences of the analytical parameters including pH, amounts of solid phase, eluent conditions (type, volume and concentrations), sample volume and interference of some metal ions on the recoveries of ions Cu²⁺, Pb²⁺, Fe²⁺, Ni²⁺ and Zn²⁺ ion were investigated. The metal ions retained on SPIMP-MWCNT was eluted using 6 mL of 4 mol L⁻¹ HNO₃ solution and their content was determined by flame atomic absorption spectrometry (FAAS) with recoveries more than 95% and relative standard deviations (n = 5) between 2.4–3.4% for both reproducibility and repeatability. The detection limit of this metal ions was between 1.0–2.6 ng mL⁻¹ (3S _b , n = 10) and their preconcentration factor was 100, while their loading capacity was above 32.9 mg g⁻¹ of SPIMP-MWCNT. The proposed method was successfully applied for the preconcentration and determination of analytes in different samples.

Keywords:

• heavy metals
• atomic absorption spectrometry
• multiwalled carbon nanotubes
• solid phase extraction