Double-Imprinted Cross-Linked Poly(Acrylamide-co-Ethylene Glycol Dimethacrylate) as a Novel Sorbent for the On-Line Preconcentration and Determination of Copper(II) by Flame Atomic Absorption Spectrometry

Abstract

An on-line preconcentration system was coupled to flame atomic absorption spectrometry (FAAS) for the determination of copper(II) in water using poly(acrylamide-co-ethylene glycol dimethacrylate) synthesized via a hierarchical double-imprinting process. The on-line preconcentration procedure was based on loading the sample into a minicolumn packed with the synthesized material, followed by elution with 1.8 mol L⁻¹ HNO₃. To achieve the highest performance, the method was optimized by 2^5-1 fractional and 2² full factorial designs. Under the optimum conditions, the following analytical parameters were obtained: detection limit of 0.48 µ gL⁻¹, quantification limit of 1.61 µgL⁻¹, preconcentration factor of 31.0, consumption index of 0.58 mL, preconcentration efficiency of 8.63 min⁻¹, and sample throughput of 15 h⁻¹. The precision of the method was evaluated as the relative standard deviation (n=10) of 10.0 and 150.0 µgL⁻¹ copper(II), yielding values of 3.27% and 1.97%, respectively. The analytical efficacy of the proposed method was justified by successful determination of copper(II) in water. The synergistic effects of copper(II) and cetyl trimethylammonium bromide, employed as templates, improved the preconcentration, thus improving the method without the double imprinting effect.

Keywords:

• Flame atomic absorption spectrometry
• Flow injection analysis
• Hierarchical double-imprinting process
• Ion-imprinted polymer

Notes

Note: Preconcentration volume (PV) = 20.0 mL; Eluent = HNO₃.

^a sodium acetate buffer.

^b sodium phosphate buffer.

Note: PV = preconcentration volume (mL); PF = preconcentration factor; CI = consumption index (mL); ST = sample throughput (h⁻¹); CE = concentration efficiency (min⁻¹); DL = detection limit (µg L⁻¹); Poly(EGDMA–MAH/Cu²⁺) = poly(ethylene glycol dimethacrylate-methacryloylamidohistidine)/Cu²⁺; Poly(EGDMA-QZ/Cu²⁺) = poly(ethylene glycol dimethacrylate-quinizarin)/Cu²⁺.

Note: ND = not detected.

^*The results are expressed as mean of three replicates.