Development of a molecularly imprinted polymeric membrane for determination of macrolide antibiotics from cow milk

A molecular imprinted membrane (MIM) was prepared for the selective binding of macrolide antibiotics by UV-initiated non-covalent imprinting approach. The membrane was modified by a UV-photographting technique in the presence of molecule templates of erythromycin (ERY) and spiramycin (SPI) with methacrylic acid (MAA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker. The nanofunctionalized MIM obtained was characterized by a morphological study using scanning electron microscopy (SEM), as well as by a study of its adsorption capacity by online solid phase extraction (SPE) procedure. Variables affecting the MIM-SPE method were optimized to maximize the extraction of macrolide antibiotics of interest and a high-performance liquid chromatography (HPLC) method was used for the analysis. Good linearity and precision were obtained for ERY and SPI, with average recoveries up to 86.14% and 34.73%, respectively, with a relative standard deviation (RSD) lower than 6%. In addition, selectivity was studied for other macrolides with similar structure to the templates, such as roxithromycin (ROX), josamycin (JOS), ivermectin (IVER) and tylosin (TYL). The proposed MIM-SPE-HPLC methodology was effectively applied to ERY and SPI determination in commercial doped semi-skimmed cow's milk samples.