RESUMO
An electrochemical sensor was fabricated for determination of cholesterol ( ChO ) based on the molecularly imprinting and signal amplification of graphene. The sensor was prepared by electropolymerizing phenol on the surface of graphene modified glassy carbon electrode with ChO as template. The structure, properties and molecular imprinting effect of the imprinted membrane were studied by SEM, CV and DPV. The results showed that the sensor had good selectivity and high sensitivity to cholesterol. The calibration graph for the determination of cholesterol was linear in the range of 8. 0 × 10-8-2. 0 × 10-4 mol/L, with the detection limit (S/N=3) of 5. 6×10-8 mol/L. The sensor was applied to the determination of cholesterol in human serum samples with satisfactory results.
RESUMO
An electrochemical sensor was fabricated for determination of cholesterol ( ChO ) based on the molecularly imprinting and signal amplification of graphene. The sensor was prepared by electropolymerizing phenol on the surface of graphene modified glassy carbon electrode with ChO as template. The structure, properties and molecular imprinting effect of the imprinted membrane were studied by SEM, CV and DPV. The results showed that the sensor had good selectivity and high sensitivity to cholesterol. The calibration graph for the determination of cholesterol was linear in the range of 8. 0 × 10-8-2. 0 × 10-4 mol/L, with the detection limit (S/N=3) of 5. 6×10-8 mol/L. The sensor was applied to the determination of cholesterol in human serum samples with satisfactory results.
RESUMO
A novel electrochemical sensor for the determination of podophyllotoxin (PPT) was prepared by modifying a PPT-imprinted membrane, which was synthesized by in situ polymerization with PPT as template, methacrylic acid ( MAA) as functional monomer and ethylene glycol dimethacrylate ( EGDMA) as cross linking agent at the molar ratio of PPT/ MAA/ EGDMA as 1 : 2 : 100, on glassy carbon electrode ( GCE) followed by eluting PPT from the modified GCE with methanol/ acetic acid (1: 1, V/ V). The properties of the electrochemical sensor modified with PPT-imprinted membrane were characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS). Under the optimum conditions, it was found that the response of peak currents was linear to the concentration of PPT in range of 1. 0 - 120 μmol/ L with the detection limit of 0. 47 μmol/ L. The sensor not only showed high selectivity, but also exhibited good stability and reproducibility. The sensor was satisfactorily applied to the determination of PPT in podophyllum hexandrum and human serum samples with the relative standard deviation (RSD) below 3. 9% and recovery ranging from 95. 0% to 103. 3% .