Electrochemical Sensor Based On Metal Nanoparticle Composites

Electrochemical sensor is a cross-disciplinary field formed by the interpenetration of multiple disciplines.Due to its simple operation,high analysis speed,and high sensitivity,electrochemical sensor is widely used in various detection fields.The novel nanomaterial modified electrodes can change the properties and functions of the electrode as to improve the analytical ability toward the target analytes.This paper prepared several different nanocomposites based on metal particles and applied them to different analytes.The main contents include the following three aspects:(1)A reducing graphene oxide(RGO)film was electrodeposited on the glassy carbon electrode(GCE),then the cobalt nanoparticles(CoNPs)was dropped on the deposited graphene.The modified electrode based on graphene/CoNPs(CoNPs/RGO/GCE)was used to determine trace Pb2+ by anodic stripping voltammetry(ASV).The amount of CoNPs,pH of buffer solution,deposition potentional and deposition time were optimized.The results showed that the signal of the CoNPs/RGO/GCE was obviously increased.Under the optimal conditions,the response current and the concentration of Pb2+ was in a linear range from 1 to 1000 ng mL-1 and the detection limit is 0.1 ng mL-1.The repeatability and reproducibility were investigated with RSD of 2.07%and 3.13%(n=6),respectively.Owing to its simple fabrication,high sensitivity,fast response,good stability and repeatability,the proposed method can be applied to the rapid determination of Pb2+ in water samples.(2)The platinum nanoparticles/cuprous oxide nanospheres were vulcanized with excessive sodium sulfide and the platinum nanoparticles/sulfide hollow nanospheres(Pt/CuSHNs)were synthesized by one step method.The Pt/CuSHNs nanocomposites modified electrodes(Pt/CuSHNs/GCE)was used as working electrode,and applied to detect H2O2 by chronoamperometry.The experimental results show that the Pt/CuSHNs/GCE obviously enhances the current signal of H2O2 compared with that of the Pt modified electrode(Pt/GCE)and CuSHNs modified electrode(CuSHNs/GCE).The amount of Pt/CuSHNs,the applied potential and the pH value were optimized.Under the optimized experimental conditions,the response current and the concentration of hydrogen peroxide show a great linear relationship in the range of 10 ?M to 8 mM.The linear equation is y=14.7429x-0.2110(r=0.9901),and the detection limit is 10 ?M.The proposed method is simple,sensitive and fast.(3)Carbon nanotubes and palladium precursors were mixed,ethylene glycol as reducing agent,and hydrochloric acid as plasticizer to synthesize palladium icosahedron/carbon nanotubes(PdICO/CNT)nanocomposites.The quantification of human IgG was achieved by using PdICO/CNT nanocomposites modified electrodes(PdICO/CNT/GCE)as the sensing interface.The differential pulse voltammetry(DPV)method was used to characterize each step of the assembly process as well as human IgG detection.The goat anti-human IgG antibody incubation time,goat anti-human IgG concentration,and human IgG incubation time was optimized.The differential pulsed voltammetric response and human IgG concentration showed a good linear relationship in the range of 0.1 ng·mL-1 to 2 ?g·mL-1,the detection limit was 0.08 ng·mL-1.The proposed sensor is rapid and sensitive and has potental applications in electrochemical immunosensors.