Application of Ni(II)-imprinted cross-linked poly(methacrylic acid) synthesised through double-imprinting method for the on-line preconcentration of Ni(II) ions in aqueous media

Abstract

The present paper describes the feasibility of on-line preconcentration of nickel ions from aqueous medium on Ni(II)-imprinted cross-linked poly(methacrylic acid) (IIP) synthesised through a double-imprinting method and their subsequent determination by FAAS. The proposed method consisted in loading the sample (20.0 mL, pH 7.25) through a mini-column packed with 50 mg of the IIP for 2 min. The elution step was performed with 1.0 mol L⁻¹ HNO₃ at a flow rate of 7.0 mL min⁻¹. The following parameters were obtained: quantification limit (QL) – 3.74 µg L⁻¹, preconcentration factor (PF) – 36, consumption index (CI) – 0.55 mL, concentration efficiency (CE) – 18 min⁻¹, and sample throughput – 25 h⁻¹. The precision of the procedure assessed in terms of repeatability for ten determinations was 5.6% and 2.5% for respective concentrations of 5.0 and 110.0 µg L⁻¹. Moreover, the analytical curve was obtained in the range of 5.0–180.0 µg L⁻¹ (r = 0.9973), and a 1.64-fold increase in the method sensitivity was observed when compared with the analytical curve constructed for the NIP (non-imprinted polymer), thus suggesting a synergistic effect of the Ni(II) ions and CTAB on the adsorption properties of the IIP. The practical application of the adsorbent was evaluated from an analysis of tap, mineral, lake and river water. Considering the results of addition and recovery experiments (90.2–100 %), the efficiency of this adsorbent can be ensured for the interference-free preconcentration of the Ni(II) ions.

Keywords:

• double-imprinted polymer
• FAAS
• Ni(II)-imprinted cross-linked poly(methacrylic acid); preconcentration

Acknowledgements

The authors are grateful to the CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico), the CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior), the INCT for Bioanalytics (Instituto Nacional de Ciência e Tecnologia de Bioanalítica) and Fundação Araucária do Paraná for their financial support and fellowships.