ABSTRACT
An innovative,ternary nanocomposite composed of overoxidized poly(3,4-ethylenedioxythiophene)(OPEDOT),gold nanoparticles (AuNPs),and electrochemically reduced graphene oxide (ERGO) was prepared on a glassy carbon electrode (GCE) (OPEDOT-AuNPs-ERGO/GCE) through homogeneous chemical reactions and heterogeneous electrochemical methods.The morphology,composition,and structure of this nanocomposite were characterized by transmission electron microscopy,scanning electron microscopy,X-ray diffraction,and X-ray photoelectron spectroscopy.The electrochemical properties of the OPEDOT-AuNPs-ERGO/GCE were investigated by cyclic voltammetry using potassium ferricyanide and hexaammineruthenium(Ⅲ) chloride redox probe systems.This modified electrode shows excellent electro-catalytic activity for dopamine (DA) and uric acid (UA) under physiological pH conditions,but inhibits the oxidation of ascorbic acid (AA).Linear voltammetric responses were obtained when DA concentrations of approximately 4.0-100 μM and UA concentrations of approximately 20-100 μM were used.The detection limits (S/N=3) for DA and UA were 1.0 and 5.0 μ.M,respectively,under physiological conditions and in the presence of 1.0 mM of AA.This developed method was applied to the simultaneous detection of DA and UA in human urine,where satisfactory recoveries from 96.7％ to 105.0％were observed.This work demonstrates that the developed OPEDOT-AuNPs-ERGO ternary nano-composite,with its excellent ion-selectivity and electro-catalytic activity,is a promising candidate for the simultaneous detection of DA and UA in the presence of AA in physiological and pathological studies.
ABSTRACT
The Poly(3,4-ethylenedioxythiophene) graphene ( PEDOT-rGO) composite film was prepared by one step pulse potentiostatic method, based on the π-π* interaction and the polymerization reaction of hydrogen bond between the graphene ( rGO) and the aromatic ring of 3,4-ethylenedioxythiophene ( EDOT) monomer. Then the nickel nanoparticles ( NiNPs ) were electrodeposited on composite film to obtain a composite film-modified glassy carbon electrode ( NiNPs/PEDOT-rGO/GCE ) . The catalytic performance of NiNPs/PEDOT-rGO/GCE towards the oxidation of glucose was studied by electrochemical method. The experimental results showed that the NiNPs/PEDOT-rGO/GCE could be used as a nonenzyematic sensor for detection of glucose. This method had high stability, good selectivity, wide linear range ( 2 μmol/L-58 mmol/L) and low detection limit (0. 7 μmol/L), realizing the rapid and sensitive detection of glucose.
ABSTRACT
A new biosensor was prepared based on conductive polymer poly ( 3 , 4-ethylenedioxythiophene ) ( PEDOT) and 1-pyrenebutanoic acid ( PBA) through π-π stacking, as well as hematin associated with PBA through coordinate bonds of Zr4+ and carboxyl group. Its stability and sensitivity were examined by cyclic voltammetry ( CV) , electrochemical impedance spectroscopy ( EIS) and current-time ( i-t) method. A pair of well defined and quasi-reversible redox peaks was observed when GCE/PEDOT/PBA/hematin was tested by CV in PBS without oxygen. The electron transfer rate constant was estimated to be 4. 8 s-1 . Results indicated that the PEDOT film enhanced the electron transfer process of hematin. When the i-t method was used to detect the response of biosensor to catechol with different concentrations, it displayed a linear response for the reduction of catechol in the range of 0. 5-200 μmol/L. The linear equation was i=0. 018C+0. 006 ( R=0. 9998), and the detection sensitivity was 0. 258 μA (μmol/L· cm2) with a detection limit of 0. 33 nmol/L (S/N=3). The results illustrate that the GCE/PEDOT/PBA/hematin biosensor is very sensitive and stable.