ABSTRACT
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 5.0×10-7 mol/L to 4.0×10-3 mol/L (R=0.9995), with a detection limit of 3.2×10-8 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%.
ABSTRACT
Toimprovethesensitivity,aCuOnanoparticledopedinmolecularlyimprintedpolymer(MIP)film for the determination of phenobarbital was prepared by using methacrylic acid as functional monomers, ethylene glycol maleic rosinate acrylate as a cross linking agent by thermal polymerization method. The electrochemical properties of the nano-doped sensor were investigated using cyclic voltammetry ( CV ) , differential pulse voltammetry ( DPV ) , electrochemical impedance spectroscopy ( EIS ) and chrono-amperometry ( CA) . The chemical structures and morphologies of the imprinted films were characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. The results indicated that the sensors response value of peak current showed a linear dependence on the phenobarbital concentration in the ranges of 1. 2 × 10-7-1. 5 × 10-4 mol/L of phenobarbital. ( Linear regression coefficient=0. 9984 ) with the detection limit ( S/N=3 ) of 8. 2 × 10-9 mmol/L. The prepared sensor was successfully applied to the determination of phenobarbital in practical samples with recovery ranging from 96 . 5% to 103 . 0%.