ABSTRACT
An ultrasensitive electrochemical sensor based on polydopamine/carboxylic multi-walled carbon nano-tubes (MWCNTs-COOH) nanocomposites modified glassy carbon electrode (GCE) was presented in this work, which has been developed for highly selective and highly sensitive determination of an anti-microbial drug, metronidazole. The preparation of polydopamine/MWCNTs―COOH nanocomposites/GCE sensor is simple and possesses high reproducible, where polydopamine can be coated on the surface of MWCNTs―COOH via a simple electropolymerization process. Under optimized conditions, the proposed sensor showed ultrasensitive determination for metronidazole with a wide linear detection range from 5 to 5000μmol/dm3 and a low detection limit of 0.25μmol/dm3 (S/N = 3). Moreover, the proposed sensor has been successfully applied for the quantitative determination of metronidazole in real drug samples. This work may provide a novel and effective analytical platform for determination of me-tronidazole in application of real pharmaceutical and biological samples analysis.
ABSTRACT
Graphene and silver nanoparticles showed good application potentials in electrochemistry due to their unique folded layered structure and good catalytic performance. In this work, reduced graphene oxide-Ag nanoparticles ( rGO/AgNPs ) composite material was prepared in situ by using hydrothermal reduction synthesis method with sodium citrate as reducing agent. The material was then used as modified electrodes to study the electrochemical behaviors of bisphenol A ( BPA) . The results of cyclic voltammetry and square wave voltammetry showed that the fast oxidation-reduction reaction of BPA could occur on the rGO/AgNPs modified glassy carbon electrode and lead to the sensitive determination of BPA. Under the optimal conditions, the oxidation current of BPA was linear to its concentration in the range of 0 . 1-40 . 0 μmol/L and the detection limit was 50 . 7 nmol/L ( S/N=3 ) . The presented method was also used for the determination of BPA in plastic samples with satisfactory results.
ABSTRACT
Objective To set up the electrochemical determination method for puerarin in Radix Puerariae.Methods The electrochemical behavior and content determination of puerarin were investigated by using coulomb array detector.Results In phosphate buffer with PH 4.32,puerarin showed good linearity in the range of 0.16 ng～ 162 ng.The regression equation was A=1444.7C+ 88.635,r=0.9998(n=7),the average recovery was 96.88 %,and RSD was 0.08 %.Conclusion This method is simple and rapid,and the result is accurate and reliable.It can be used for the determination of puerarin content and biological samples.