| In this paper,the glassy carbon electrode is modified by a simple method to obtain L-methionine modified electrode（PLM/GCE）,multi-walled carbon nanotube modified electrode（MWCNTs/GCE）,nano-silver graphene multi-walled carbon nanotube composite modified electrode（AgNPs/GR/MWCNTs/GCE）,which is used for electrochemical detection of three typical phenolic pollutants and the optimal experimental conditions and reaction mechanism were explored,the main contents of the research are as follows:Ⅰ.Preparation of L-methionine modified glassy carbon electrode and electrochemical detection of p-chlorophenolThe L-methionine was modified on the bare glassy carbon electrode by cyclic voltammetry to form a dense and uniform modified film to prepare PLM/GCE.The p-chlorophenol was enriched by the time-current method and adopted differential pulse voltammetry discussed the electrochemical behavior of p-chlorophenol on the modified electrode and the optimal measurement conditions.The results show that,in the base solution system with 3 cycles of polymerization,+0.2 V as the enrichment voltage,enrichment time of 150 s,disodium hydrogen phosphate-citric acid buffer solution as the supporting electrolyte,and p H=6.0,in the concentration range of8.0×10-6～1.0×10-4mol/L,the concentration of chlorophenol has a good linear relationship with the magnitude of oxidation peak current value.The detection range is wide,the sensitivity is high,and the stability,repeatability and recovery are satisfactory.Ⅱ.Preparation of multi-walled carbon nanotubes modified glassy carbon electrode and electrochemical detection of 2,6-dimethylphenolUsing double distilled water as the dispersant,MWCNTs were ultrasonically dispersed for a long time to form a uniform turbid modification solution,and the MWCNTs were successfully modified on the bare glassy carbon electrode by a simple drip coating method to prepare MWCNTs/GCE.The modified electrode was used as a working electrode,a three-electrode system was established,and the electrochemical behavior of 2,6-dimethylphenol on MWCNTs/GCE and the optimal measurement conditions were investigated by differential pulse voltammetry.The results showed that after dropping 12μL of 1.0 mg/m L modification solution,0 V was the enrichment voltage,the enrichment time was 400 s,and the disodium hydrogen phosphate-potassium dihydrogen phosphate buffer solution was used as the supporting electrolyte,and the p H=7.0 in the base solution system,the concentration of 2,6-dimethylphenol is in the range of 2.0×10-6～1.0×10-4mol/L,and there is a good linear relationship between its concentration and the magnitude of the oxidation peak current.The sensitivity is high,the detection range is wide,and the stability and repeatability of the electrode meet the requirements.Ⅲ.Preparation of nano-silver graphene multi-walled carbon nanotube composite modified electrode and electrochemical detection of bisphenol AThe glassy carbon electrode was successfully modified with nano silver（AgNPs）,graphene oxide（GO）and multi-walled carbon nanotubes（MWCNTs）by simple dipping and electrochemical reduction methods.Prepared nano silver graphene multi-wall carbon nanotube composite modified electrode with high stability,good repeatability and wide detection range,and using differential pulse voltammetry to explore the electrochemical behavior of bisphenol A on the composite electrode and the optimal measurement conditions.The results showed that 6μL of the modification solution with a concentration ratio of 1:1 was immersed in AgNPs with a mass concentration of 0.01 mg/m L for 60 minutes,with disodium hydrogen phosphate-potassium dihydrogen phosphate as the supporting electrolyte,and the p H of the bottom solution was under the condition of 7.0,the concentration of bisphenol A is within the range of 8.0×10-6～1.0×10-4mol/L,and its concentration has an obvious linear relationship with the magnitude of the oxidation peak current.The electrochemical response is good and it can be used for the detection of bisphenol A. |
PDF Full Text Request