Abstract Molecularly imprinted microspheres (MIPs) were synthesized by precipitation polymerization using vanillin as template molecule, methacrylic acid (MAA) as functional monomer, azodiisobutyronitrile (AIBN) as initiator and ethylene glycol dimethacrylate as cross-linker. The interaction of vanillin with MAA and the recognition mechanism of vanillin MIPs were studied by UV spectroscopy, Fourier transform infrared spectroscopy (FT-IR) and 1H-NMR, and their surface morphology was observed under a scanning electron microscope (SEM). Equilibrium adsorption and isothermal adsorption experiments were carried out to investigate the vanillin-binding capacities of MIPs and non-molecularly imprinted polymers (NIPs). Smooth and regularly shaped MIPs were formed from the hydrogen bonding interaction between vanillin and MAA. They could adsorb and recognize vanillin much better than NIPs and adsorption equilibrium was reached after 120 min. Scatchard analysis showed that a homogenous distribution of vanillin-specific recognition sites were found in the MIPs, and the dissociation constant (Kd) and apparent maximum binding capacity (Qmax) were 4.243 × 10-5 mol/L and 7.357 μmol/g, respectively. The results of selective separation, solid phase extraction (SPE) and HPLC analysis indicated that these MIPs were effective in separating and enriching vanillin.
Received: 08 October 2011
Published: 12 December 2012