| Nowadays,the traditional Chinese medicines?TCMs?have been attracted worldwide attention,due to their unique curative effect in treating various diseases and small side effect.The detection of bioactive constituents of TCM plays a central role for studying the pharmacology of TCM,thus,it is very important and interesting to develop an efficient and convenient method for determination of TCM.To date,electrochemical analysis method has been widely used in the field of pharmaceutical analysis.However,the performance and efficiency of electrochemical analysis are greatly influenced by the modified materials of electrode surface,so it is necessary to explore proper modified materials and improve the performance of electrochemical sensor.Based on the advantages of carbon nanomaterials and noble metal nanoparticles in specific surface area,electroconductibility,stability and so on,the carbon nanocomposites loaded with noble metal nanoparticles were prepared and applied to detect bioactive constituents of TCM in this dissertation.First,the highly sensitive and selective electrochemical sensor of hesperidin based on gold nanoparticles?AuNPs?and reduced graphene oxide?rGO?modified glassy carbon electrode?GCE?was reported,and oxidation mechanism of hesperidin at AuNPs/rGO/GCE modified electrode was explored.The AuNPs and rGO have been characterized by scanning electron microscopy?SEM?,energy dispersive X–ray spectrometry?EDX?,X–ray photoelectron spectroscopy?XPS?,FT–IR and electrochemical methods.Under optimum conditions,hesperidin was determined quantitatively at AuNPs/rGO/GCE using amperometric i–t curve.The results showed that current of hesperidin exhibited a linear correlation with its concentration in the range of 5.0×10–8 mol L–1–8.0×10–6 mol L–1 with a detection limit of8.2×10–9 mol L–1?S/N=3?and sensibility of 18.04 A mol L–1 cm–2.In addition,the modified electrode was successfully applied to detect hesperidin in the traditional Chinese medicine,Pericarpium Citri Reticulatae.As a conventional,convenient,and cost–effective sensor,it presents a great potential for determining the trace amounts of hesperidin in the fields of pharmacy,biology,etc.Second,the nanocomposite?AuNPs/PC?was prepared by porous carbon?PC?loaded with AuNPs.The elementary composition,inner structure and surface morphology of AuNPs/PC nanocomposites have been characterized using SEM,TEM,EDX and XRD methods.The quantitative determination of magnolol based on AuNPs/PC modified Au eleltrode was conducted using differential pulse voltammetry?DPV?,and further,oxidation mechanism of magnolol at AuNPs/PC/Au electrode was explored.The results showed that the linear range,detection limit,and sensibility of the resultant sensor were estimated to be2.0×10–8-4.0×10–6 mol L–1,2.0×10–9 mol L–1?S/N=3?and 15.02 A mol L–1 cm–2,respectively,which exhibits better performance than previous detection methods.In addition,the AuNPs/PC/Au electrode was used to determine magnolol in the traditional Chinese medicine,Mangnolia Officinalis.This new sensing platform for magnolol exhibited high sensitivity,good stability and promising application.At last,PtNPs/PC nanocomposite was prepared by PtNPs deposited in situ on the surface of PC,and was characterized using SEM,TEM,EDX and XRD methods to analyze its elementary composition,inner structure and surface morphology.Under optimum conditions,the quantitative determination of rutin based on PtNPs/PC modified Au eleltrode was conducted using amperometric i–t curve.The results exhibited that the linear range,detection limit,and sensibility of the resultant sensor were estimated to be 5×10–8-4.32×10–5 mol L–1,1.25×10–9 mol L–1?S/N=3?and 22.56 A mol L–1 cm–2,respectively,which presents wider linear range than previous electrochemical sensors.In addition,the proposed sensor displayed high sensitivity,excellent stability and satisfactory results in the analysis of traditional Chinese medicine,Sophora Flower Bud. |
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