Preparation and recognition performance of cytisine alkaloid-imprinted material prepared using novel surface molecular imprinting technique

Methacrylic acid was first graft-polymerized on the surfaces of micron-sized silica gel particles in the manner of "grafting from" using 3-methacryloxypropyl trimethoxysilane as an intermedia, obtaining the grafted particle polymethacrylic acid PMAA/SiO2. By adopting the novel surface-molecular imprinting technique put forward by us, cytisine molecule-imprinted material MIP-PMAA/SiO2 was prepared with ethylene glycol diglycidyl ether as crosslinking agent. The binding characteristics of MIP-PMAA/SiO2 towards cytisine was investigated in depth with both batch and column methods and using matrine and oxymatrine as two contrast alkaloids, which with cytisine coexist in sophora alopecuroides and their chemical structure is similar to cytisine to a certain extent. The experimental results show that the surface-imprinted material MIP-PMAA/SiO2 has excellent binding affinity for cytisine (20.1 g/100 g of binding capacity), and it is more important that MIP-PMAA/SiO2 has very high recognition selectivity for cytisine in relation to the two contrast alkaloids. The selectivity coefficients of the grafted particles PMAA/SiO2 (non-imprinted material) for cytosine in relation to matrine and oxymatrine are only 1.03 and 1.06, respectively, displaying no recognition selectivity for cytisine. However, after imprinting, the selectivity coefficient of MIP-PMAA/SiO2 for cytisine in respect to matrine and oxymatrine are remarkably enhanced to 12.08 and 15.05, respectively.