| Luteolin and baicalin,both of which belong to flavonoids.It has many medicinal functions such as resisting inflammation,killing bacteria,resisting tumors and viruses,etc.Chlorogenic acid,which can be classified as phenolic acid compounds.Its pharmacological activities include antibacterial,antiviral,tumor prevention,antihypertensive and so on.In drug research and development,luteolin,chlorogenic acid and baicalin are gradually used in traditional Chinese medicine preparations.In order to ensure that their contents meet the corresponding requirements in clinical application and drug quality control,it is of great significance to detect the contents of luteolin,chlorogenic acid and baicalin quickly,accurately and sensitively.In this paper,several kinds of polymer and nano-gold composite modified electrodes were prepared,and they were used to detect luteolin,chlorogenic acid and baicalin respectively.The research contents and experimental results are as follows:（1）The electrochemical polymerization and potentiostatic deposition were used to design and modify the electrode with xylitol and nano-gold.Finally,poly（xylitol）/nano-gold modified composite electrode（PX/Au NPs/GCE）was obtained.This composite electrode was used to test luteolin.Cyclic voltammetry（CV）was selected to evaluate the characterization of the composite electrode in potassium ferricyanide solution.The conditions needed for the experiment are optimized.The results show that the peak current of luteolin obtained by differential pulse voltammetry（DPV）has a relatively wide linear concentration range under the optimum experimental conditions.The concentration ranges from 3×10-8mol/L to1×10-5mol/L.The lower detectable limit is 7×10-9mol/l.PX/Au NPs/GCE showed excellent reproducibility,stability and resistance to interference in the detection of luteolin.The recovery rate of luteolin in honeysuckle dew was determined by PX/Au NPs/GCE,and the recovery rate was in the range of 96.4%～101.9%.（2）Poly（L-serine）/graphene-gold nanoparticles modified composite electrode（PLS/GO-Au NPs/GCE）was constructed by electrochemical polymerization and drop coating method,and was used to detect luteolin.The modification and characterization of the composite electrode in potassium ferricyanide solution and the optimization of experimental conditions were carried out by CV.The results showed that luteolin was determined by DPV under the best experimental conditions.In the range of 1×10-10mol/L to 1.3×10-6mol/L,the peak current of luteolin was linearly correlated with the concentration.The lower limit for determination is 1×10-10mol/L.PLS/GO-Au NPs/GCE showed good reproducibility,stability and anti-interference ability.The recovery rate of luteolin in honeysuckle dew was determined by PLS/GO-Au NPs/GCE,and the recovery rate was in the range of 98.9%～103.3%.（3）Poly dithiothreitol/gold nanoparticles modified composite electrode（PDTT/Au NPs/GCE）was prepared by electrochemical polymerization and potentiostatic deposition,and was used to detect chlorogenic acid.The composite electrode was modified and characterized in potassium ferricyanide solution by CV and the experimental conditions were optimized.The experimental results show that the peak current of chlorogenic acid at the composite electrode measured by DPV has a good linear correlation with the concentration under the optimized experimental conditions,and the concentration ranges from 5×10-6mol/L to 2×10-4mol/L.The lower limit of permissible detection is 5×10-7mol/L.In the process of using PDTT/Au NPs/GCE to determine chlorogenic acid,it showed good reproducibility,stability and resistance to interference.PDTT/Au NPs/GCE was used to determine the recoveries of chlorogenic acid in honeysuckle extract.The recoveries ranged from97.7%to 103.1%.（4）Cetyltrimethyl ammonium bromide and gold nanoparticles were modified on the electrode by electrochemical polymerization and potentiostatic deposition.Finally,poly cetyltrimethyl ammonium bromide/nano-gold modified composite electrode（PCTAB/Au NPs/GCE）was obtained.Baicalin was measured by this composite electrode.The composite electrode was characterized and evaluated by CV in potassium ferricyanide solution.Choose the conditions needed for the experiment to optimize.The experimental results show that under the optimized conditions,baicalin was detected by DPV,and the peak current of baicalin at the composite electrode has a relatively wide linear concentration limit.The concentration ranges from 4×10-8mol/L to 5×10-5mol/L.The lower detectable limit is 1×10-8mol/L.This composite electrode showed good reproducibility,stability and anti-interference ability in the detection of baicalin.PCTAB/Au NPs/GCE was used to determine the recovery of baicalin in Sanhuang tablets,and the recovery was in the range of 97.0%～100.1%. |
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