Recognition of molecularly imprinted polymers for a quaternary alkaloid of berberine

Selective and affinitive imprinted polymers incorporating a quaternary alkaloid of berberine (BER) were prepared using a non-covalent imprinting method. The results showed that, compared to other imprinted polymers, the polymer AD-10 had not only a higher of the ratio of Q(MIP)/Q(BP) for BER adsorption, and but also a larger of the ratio of Q(MIP,B)/Q(MIP,P) for BER and palmatine (PAL) adsorptions. Spectrophotometric analysis demonstrated that a 1:1 cooperative hydrogen-bonding complex might be predominating in the pre-polymerization between the BER template and AA monomer. Adsorption experiments of BER on the polymer AD-10 were in accordance with the second-order and Langmuir adsorption models. The E value (5.70 kJ/mol) calculated from the Dubinin-Radushkevich model indicated that the adsorption followed a physisorption process. In addition, a Scatchard plot showed a single straight line with an equilibrium dissociation constant (K(D)) of 65.80 μmol/L. SPE analyses of a mixture of BER and PAL and the methanol extract from the cortices of Phellodendron wilsonii showed that AD-10 had more efficiency, and higher specificity and selectivity for SPE in the concentration and determination of BER and its extraction from natural products.