Design Of Novel Chemically Modified Electrodes For Electrochemical Detection Of Paracetamol

As an analgesic and antipyretic veterinary drug,paracetamol will remain in animal husbandry.Paracetamol in animal husbandry meat products is continuously enriched in human body,and it will be harmful to human health if it reaches a certain concentration.Therefore,the determination of paracetamol is an important item in food safety monitoring.It is of great significance to research and develop a rapid and accurate detection method for paracetamol for ensuring food safety and quality and safeguarding human health.Traditional detection methods,such as gas chromatography,liquid chromatography and mass spectrometry,have the disadvantages of complicated pretreatment,expensive equipment,slow detection speed and inconvenient detection outside the laboratory.Electrochemical analysis method has obvious advantages over traditional methods in simplicity,detection speed and cost,so the research work of this paper focuses on the new electrochemical detection method of paracetamol.In this paper,paracetamol is taken as the analysis object,and two kinds of electrochemical sensors with simple modification method,cheap modification materials,short electrode modification time and high sensitivity are constructed.The research contents and results of this paper are as follows.In the first part of this paper,the modified electrode of reduced graphene oxide-Nafion composite film was prepared by one-step electrochemical reduction method based on glassy carbon electrode(GCE),and a fast and sensitive electrochemical sensor for the electrochemical detection of paracetamol was constructed.Firstly,graphene oxide was mixed with Nafion solution and dripped on the surface of glassy carbon electrode to form a composite membrane.Then,the modified electrode was partially reduced by applying a suitable reduction potential in a buffer solution to prepare a partially reduced graphene oxide-Nafion composite membrane modified electrode.The electrochemical properties of the modified electrode were characterized by cyclic voltammetry,and the effects of the p H value of buffer solution,the standing time of the modified electrode in the buffer solution containing paracetamol and the number of reduction cycles of the modified electrode on the electrocatalytic activity of the modified electrode were investigated.The experimental results show that under the optimal conditions,the concentration of paracetamol solution is linearly related to its response current in the range of 0.05μmol/L～20μmol/L,the linear equation is Y=2.7556X+1.1081(R~2=0.9959),the detection limit is 20 nmol/L,and the recovery rate is 94%～103%.The sensor has low detection limit,wide linear range and good selectivity,and can be used to detect paracetamol in practical samples with accurate results.In the second part of the paper,a novel glassy carbon electrode modified by sodium carboxymethylcellulose(CMC)was designed,and a rapid and sensitive electrochemical sensor for the detection of paracetamol was constructed.Firstly,the glassy carbon electrode was used as the substrate,and an oxidation potential of 1.8 V was applied in the electrolyte solution to prepare the oxidized glassy carbon electrode.Then sodium carboxymethylcellulose was added dropwise to its surface to prepare the oxidized glassy carbon electrode modified by sodium carboxymethylcellulose.By changing the oxidation time of the modified electrode,the oxidation degree of the composite membrane was adjusted,and the influence of sodium carboxymethylcellulose modified oxidized glassy carbon electrode prepared at different oxidation time on the current signal of paracetamol was investigated.The sensor can eliminate the interference of ascorbic acid and dopamine in the detection of paracetamol,and has good selectivity and anti-interference.The results show that the linear equation of the electrochemical sensor based on oxidized glassy carbon electrode and sodium carboxymethylcellulose modified electrode for the detection of paracetamol is Y=3.2622X+0.6627(R~2=0.99958),the detection limit is 10 nmol/L,and the linear range is 0.04μmol/L～50μmol/L..The sensor was used to determine the content of paracetamol in practical samples with good recovery.