3.3. Evaluation of the adsorption characteristic of BPA-imprinted silica nanoparticles
Dynamic adsorption test was carried out at different time inter- vals. It showed that the BPA adsorption reached the equilibrium within 40 min. For further studies, an incubation period of 60 min was therefore considered as sufficient, which usually needs more than ten hours reported in the literature [32]. The rapid rebind- ing kinetics of BPA-imprinted silica nanoparticles is attributed to the most recognition sites at the surface or in proximity to the surface of the particles for easy diffusion of target analytes into imprinting cavities. This merit is favorable for BPA-imprinted silica nanoparticles used as SPE sorbent.
To measure adsorption capacity of BPA-imprinted sorbent pre- pared herein, BPA toluene solutions with different concentrations (varied from 100 to 5000