Molecular recognition properties of salicylic acid-imprinted polymers

Two molecularly imprinted polymers (MIP) have been prepared using the acidic drug salicylic acid, which can form intramolecular hydrogen bond, as the template and acrylamide or 4-vinylpyridine as the functional monomer. HPLC was used to evaluate the binding performance of the MIP for the template and for several analogues. The results showed that the MIP (P-2) prepared using acrylamide as the functional monomer had no molecular imprinting effect whereas that (P-1) prepared using 4-vinylpyridine as the functional monomer had a significant molecular imprinting effect. The reason the molecular imprinting effect was different for the two MIP was elucidated and the molecular recognition properties of P-1 were studied in detail. it was confirmed that electrostatic interaction played an important role in the molecular recognition of P-1. Scatchard analysis showed that two types of binding site with distinctly different affinity were formed in P-1. Their dissociation constants were estimated to be 7.6 x 10(-5) mol L-1 and 3,2 X 10(-3) mol L-1, respectively. Because P-1 has high affinity and selectivity for salicylic acid not only in organic systems but also in water-containing systems, it gives P-1 the potential for use in the enrichment, separation, and detection of salicylic acid in biological fluids.