In this work, water-compatible molecularly imprinted polymers (MIPs) were prepared for fast, accurate and selective solid-phase extraction of verapamil (VPM) from complex matrices such as biological fluids and human urine followed by its UV spectroscopic determination at 278 nm. The effective factors influencing the precipitation polymerization have been studied. Molecular recognition properties, binding capability and selectivity of the MIPs were evaluated and the results revealed that the obtained MIPs have high affinity for VPM in aqueous media. Equilibrium binding experiments were done to assess the performance of the MIP relative to non imprinted polymer (NIP). After optimization of molecularly imprinted solid-phase extraction (MISPE) method with 2 mL water plus 2 mL acetone as washing solvents and 5 mL of methanol and acetic acid (10:1, v/v) as elution solvent, successful imprinting was confirmed by comparison of the recoveries between NIP (4%) and MIP (97%) polymers. The binding capacity of the MIP for VPM was determined to be 196 mg g-1 (400 μmol g-1). Accuracy and precision were checked by the HPLC technique and the results did not present significant difference at 95% confidence levels according to the t-test.
Keywords: Molecularly imprinted polymer, Solid-phase extraction, Verapamil, Biological fluids, Human urine