Simultaneous separation and preconcentration of trace amounts of copper (II), cobalt (II) and silver (I) by modified Amberlyst®15 resin

Abstract

A solid phase extraction method for simultaneous preconcentration and separation of trace amounts of copper, cobalt and silver in different samples, using a column packed with modified Amberlyst®15 resin is developed. Amberlyst®15 resin was modified with 5-(4-dimethylaminobenzylidene)rhodanine and then the modified resin was used as a support material for the solid phase extraction and preconcentration of Cu(II), Co(II) and Ag(I) ions from aqueous solution in the pH range 3.5–4.5. The adsorbed metal ions on the column were quantitatively eluted with a 7% thiourea solution prepared in 2 mol L⁻¹ HNO₃, which were detected by flame atomic absorption spectrometry. The effects of analytical parameters including pH of the solution, eluent type, flow rate of samples, eluent and matrix ions were investigated for optimization of the presented procedure. The detection limits were 2.1, 0.9 and 0.9 ng mL⁻¹ for Cu(II), Co(II) and Ag(I) ions, respectively based on the three times the standard deviations of the blanks. The preconcentration factor was 112.5. The calibration graphs were obtained in the ranges of 0.05 to 10.0, 0.03 to 13.0 and 0.04 to 9.0 µg mL⁻¹ for Cu(II), Co(II) and Ag(I) ions concentrations, respectively. Relative standard deviations (n = 7) for Cu(II), Co(II) and Ag(I) ions were found ±2.5 %, ±0.84% and ±3.8% respectively. The method was applied to the determination of mentioned ions in well water, waste water and lettuce sample.

Keywords:

• solid phase extraction
• preconcentration
• copper determination
• cobalt determination
• silver determination
• water analysis
• modified Amberlyst®15

Acknowledgements

This paper is dedicated to the memory of the founder of Kerman University, Mr Alireza Afzalipour, on the occasion of the century of his birth.