Preparation and Recognition Properties of Trimethoprim Sensor Based on Palladium Nanoparticles-modified Molecularly Imprinted Polymer

To improve the sensitivity of molecularly imprinted electrochemical sensors, a Pd nanoparticles- modified molecularly imprinted polymer (MIP) film for the determination of trimethoprim (TMP) was developed by thermal polymerization with N, N'-methylene diacrylamide as a functional monomer, Pd nanoparticle as a dopant and ethylene glycol maleic rosinate acrylate as a crosslinking agent. The morphologies and chemical structures of the Pd nano. materials and the imprinted films were characterized using Fourier transform infrared spectroscopy and scanning electron microscopy, respectively. The electrochemical properties of the nano. doped and undoped MIP sensors were investigated by cyclic voltammetry and electrochemical impedance spectroscopy. Results showed that the morphologies and chemical structures and the electrochemical properties of the doped molecularly imprinted sensor were remarkably different from those of the undoped imprinted sensor. Linear responses of the imprinted sensor to TMP were observed for concentrations ranging from 5. 0x10(-7) mol/L to 4. 0x10(-3) mol/L (R = 0. 9995), with a detection limit of 3. 2x10(-8) mol/L (S/N = 3). The Pd nanoparticle doped MIP sensors exhibited high selectivity. The chronoamperometry showed that no interference from potential interfering species such as sulfamethoxazole, sulfadiazine, glucose, and urea were noted. The proposed electrochemical sensor was used to determine TMP in actual samples, with average recoveries of 96. 8% -102. 0%.