Sildenafil Magnetic Molecularly Imprinted Polymers, In Prohibited Drug Analysis

Nowadays, food and drug safety issue has been a highlight of the world. Lots ofevidences are coming into literature about adulteration of herbal health care productswith synthetic drugs or their congeners, in order to enhance the claims stated on thelabel. Prolonged or excessive consumption of these supplements containingundeclared amounts of drugs may cause serious adverse health consequences. Theingredient of the synthetic drugs is complex and in low concentration, and the mutualinterference among the complex matrix (especially the ingredient of traditionalChinese medicine) makes the determination difficult. Sample pretreatment methodwas tedious and lack of selectivity. Therefore, the research to develop efficientanalytical method on illicit substances in functional food and drug has an importantsignificance.An analytical procedure for selective extraction of sildenafil and vardenafil inHDSs has been set up by using the magnetic molecularly imprinted polymers(MMIPs) as the extraction and clean-up materials, followed by high performanceliquid chromatography-ultraviolet (HPLC-UV). MMIPs were prepared by a surfacemolecular imprinting technique, using Fe3O4 magnetite as a magnetically susceptiblecomponent, sildenafil as template molecule, 2-(trifluoromethyl) acrylic acid(TFMAA) as functional monomer, ethylene glycol dimethacrylate (EGDMA) aspolymeric matrix components. MMIPs were characterized by transmission electron microscope (TEM), fourier transform infrared spectrometer (FT–IR), X–raydiffraction (XRD) and vibrating sample magnetometer (VSM), respectively. Theheterogeneity and adsorption property of MMIPs were modeled with the Freundlichand Langmuir isotherm equation, respectively. The resulting MMIPs had highrecognition ability and fast binding kinetics for sildenafil. MMIPs were used asdispersive solid-phase extraction (DSPE) materials to selectively extract sildenafiland vardenafil from HDSs, the contents of sildenafil and vardenafil were found to be8.05 and 3.86μg g-1, respectively, and the average recoveries in spiked HDSs were70.91-91.75% with a relative standard deviation (R.S.D.) below 7%. The MMIPswere successfully used to selectively enrich and determine sildenafil and vardenafilfrom HDSs.