A Highly Permeable Membrane for Separation of Quercetin Obtained by Nickel(II) Ion-Mediated Molecular Imprinting

Abstract

A polymer membrane imprinted with quercetin has been synthesized in the presence of nickel(II) acetate as a metal ion mediator. A mixture of methacrylic acid (MAA), ethylene glycol dimethacrylate (EGDMA), tetrahydrofuran (THF) – methanol (3:1 v/v) as a solvent and Darocur® 1173 (2-hydroxy-2-methyl-1-phenyl-propan-1-one) as a photoinitiator was polymerized on a track-etched membrane (pores 0.4 µm) used as a support. The polymer formed regular layers on both sides of the membrane and filled the pores. The highest initial flux of the template of 1.8 · 10⁻⁷ mol · cm⁻² · h⁻¹ was observed for its diffusion from THF/acetate buffer (20:80, v/v) into THF. Membranes polymerized with nickel(II) were both more permeable and more selective. The maximum selectivity factors, calculated by using percent permeation, were 4.5 (quercetin/rutin) and 4.9 (quercetin/naringenin).

Keywords:

• molecular imprinting
• photopolymerization
• preconcentration by membrane diffusion
• quercetin
• track-etched membranes

ACKNOWLEDGEMENTS

The authors are grateful to the Russian Foundation for Basic Research for financial support (project No 10-03-01023-a) and Elena Khanonina (BASF Russia) for the sample of Darocur® 1173.

Notes

*Notes. References to the publications of 1990-s can be found in paper (3); the fluxes do not exceed 2 · 10⁻⁸ mol · cm⁻² · h⁻¹. Many other MIMs have only been characterized in sorption or filtration experiments (15,32,34,35,43), in which cases the diffusion flux data are unavailable.

*Note. For conditions, see Fig. 3.

*According to the position of the membrane during polymerization.

Notes. Permeation across initial track-etched TM under these conditions was 29 ± 3%. Data have been obtained form 5 diffusion runs, and uncertainties calculated for the significance level of 0.95.

*Note. For conditions, see Fig. 3.

*Notes. Feed: THF:0.5 M acetate buffer, pH 5.4 (20:80, v/v); initial concentrations: 5 · 10⁻⁴ M quercetin, 1.5 · 10⁻³ M Ni(CH₃COO)₂; receiving phase: THF; t = 15 min; n = 3, P = 0.95. For polymerization conditions, see Fig. 3.

*Mixed directly before diffusion.

**Quercetin and Ni(CH₃COO)₂ solutions were mixed 15 min before diffusion.

*Notes. For other polymerization and diffusion conditions, see Fig. 3. Average values and uncertainties were calculated from 3 parallel diffusion runs (P = 0.95).

*Note. For other conditions, see Fig. 3.

*Note. For other conditions, see Fig. 3.