Preparation of ractopamine molecularly imprinted polymers and its chromatographic characterization

Molecularly imprinted polymers(MIP) with high selectivity to ractopamine(RAC) were prepared in ethanol using ractopamine as a template,methacrylic acid as a monomer,and ethylene glycol dimethacrylate as a cross-linker by precipitation polymerization,The binding capacity of the polymer toward RAC was found to be about 145.6 μg of ractopamine / g of polymer.The MIP microspheres were packed into high performance liquid chromatographic(HPLC) column(50 mm × 4.6 mm i.d.).The imprinted factor(IF) of the imprinted column reached 1.2.The capacity factors(k) of the imprinted column and the non-imprinted column towards ractopamine were calculated as 33.3 and 15.1,respectively.The results showed that there is a good imprinting effect of the imprinted column to ractopamine.Additionally,the selectivity factors(α) of the imprinted column for clenbuterol,salbutamol and ractopamine were evaluated using HPLC.The results showed that the selectivity factors(α) of the column for clenbuterol and salbutamol were 2.3 and 1.2,respectively.The imprinted column possessed high selectivity to these three β-agonists.