| A new molecularly imprinted polymer (MIP) was specifically synthesized as a smart material for the recognition of metformin in solid-phase extraction. Particles of this MIP were packed into a stainless-steel tube (50 mm x 0.8 mm i.d.) equipped with an exit frit. This micro-column was employed in the development of a molecularly imprinted solid-phase extraction (MISPE) method for metformin determination. The MISPE instrumentation consisted of a micrometer pump, an injector valve equipped with a 20-mul sample loop, a UV detector, and an integrator. A systematic investigation of binding selectivity was conducted with respect to sample solvent, matrix, pH, surfactant effects and buffer compositions.; In addition, a SPE-CE method was developed for the determination of metformin and phenformin in human plasma. Coupled at line to capillary electrophoresis (CE), solid phase extraction (SPE) using a C18 cartridge was employed to remove most of the water and proteins from the plasma sample. CE analysis was performed using a non-aqueous buffer, acetonitrile + 20 mM ammonium acetate + 5% acetic acid, which afforded rapid separation of metformin from phenformin within 3 min. (Abstract shortened by UMI.)... |
