Selective Adsorption of Tetrahydropalmatine by a Molecularly Imprinted Polymer with Modified Rosin Cross-linker

A molecularly imprinted polymer (MIP) containing a phenanthrene skeleton was prepared by suspension polymerization with ethylene glycol maleic rosinate acrylate (EGMRA) as the cross-linker, tetrahydropalmatine (THP) as the template, and methacrylic acid as the functional monomer. A non-imprinted polymer (NIP) was similarly prepared and treated, but in the absence of THP. The MIP and NIP were characterized by scanning electron microscopy and nitrogen sorption and thermal gravimetric analyses. The time taken by the MIP to reach THP (C0 = 2.8 mmol L –1) adsorption equilibrium was 4.5 h, and the recog-nition factor of the MIP for THP was 2.09. The change in microcalorimetric heat flow during adsorption revealed that the MIP had a higher affinity to THP compared with NIP. Selective adsorption experiments demonstrated the high affinity and THP selectiv-ity of the MIP