Abstract:

Novel molecularly imprinted polymer (MIP) microspheres were prepared by the precipitation polymerization method using 2-isopentyl cyclopentanone as the dummy template. The surface chemical groups were characterized by Fourier transform infrared spectroscopy (FTIR) and the particle size distribution was characterized by scanning electronic microscope (SEM). Adsorption dynamics, isotherm adsorption behavior and application capacity for this MIP in solid phase extraction of rose oxide were explored. The results indicated that MIPs could reach adsorption equilibrium within 25 min, showing a rapid adsorption dynamics, and the first order model was better to describe its adsorption dynamics behavior. Additionally, the Freundlich isotherm model was more suitable to describe the isotherm adsorption behavior and a maximum binding site number (149.3 μmol/g) was obtained by fitting the isotherm data to the Langmuir model. A mean adsorption potential energy of 166.7 kJ/mol indicated a chemical adsorption process for MIPs. The selectivity factor for MIPs toward rose oxide relative to geraniol and citronellol was 3.710 and 5.636, respectively. Especially, this MIP possessed higher competitive adsorption capacity toward rose oxide in the mixture, with an adsorption capacity of 18.03 mg/g. Under the optimized solid phase extraction conditions, i.e., washing by using 1 mL acetonitrile, 1 mL acetonitrile-water mixture(volume ratio 9.5:0.5) and 2 mL acetonitrile-methanol-water mixture (volume ratio 8:1:2) and eluting by using 3 mL methanol-acetic acid mixture(volume ratio 9:1), rose oxide can be separated and enriched from crude rose extract by using molecularly imprinted polymeric solid phase extraction, with a recovery of 96.23%.

Key words: dummy template imprint, molecularly imprinted microsphere, rose oxide, adsorption, extraction