Solid phase extraction of trace metals in water and leafy vegetables using a resin functionalized with potassium 2-benzoylhydrazinecarbodithioate and determination by ICP–AES

Abstract

A solid phase extraction method for the determination of Cu(II), Mn(II) and Zn(II) metal ions in natural water and leafy vegetable samples by ICP-AES was developed. The method was based on the sorption of metal ions onto Amberlite XAD-16 functionalized with a new chelating ligand potassium 2-benzoylhydrazinecarbodithioate (Amberlite XAD-16-PBHCD) and elution with nitric acid. The optimum experimental conditions for the quantitative sorption of the three metal ions, namely, effect of pH, sample volume, flow rate, concentration of eluent, sorption capacity, kinetics of sorption, and the effect of diverse ions on the sorption of analytes have been investigated. All the metal ions were quantitatively retained by the functionalized resin at pH 5.0 and sorbed metals could be eluted with 2.0 M HNO₃. The detection limits were 5.6, 4.5 and 1.8 µg L⁻¹ for Cu(II), Mn(II) and Zn(II), respectively. The developed method was applied for the determination of Cu(II), Mn(II) and Zn(II) in water and leafy vegetable samples.

Keywords:

• solid phase extraction
• Amberlite XAD-16
• PBHCD
• metal ions
• ICP-AES
• leafy vegetables

Acknowledgements

The authors are highly thankful to UGC, New Delhi for financial assistance (F.No. 33-297/2007 (SR)). The authors are also thankful to NGRI, Hyderabad for providing ICP-AES facilities and standard reference materials.