Preparation Of AuNPs@PPY/GCE Electrochemical Eensor And Detection Of Formaldehyde In Milk

At present,there are many problems in the commonly used detection methods for formaldehyde,such as long time consuming,expensive instruments and poor sensitivity,so it is necessary to develop a simple and economical method for formaldehyde detection.In this paper,polypyrrole materials,gold nanoparticle materials and electrochemical techniques are linked.Gold nanoparticles and polypyrrole were modified onto glassy carbon electrode to form a AuNPs@PPY/GCE sensor,which will be used to detect formaldehyde.Parameters of the sensor preparation process are optimized.In order to make the sensor have higher sensitivity.The effect of large overpotential treatment of polypyrrole on the modification of gold nanoparticles was explored.After that,AuNPs@PPY/GCE sensor detect formaldehyde and analyze the electrochemical catalytic reaction process.The performance of the sensor was evaluated.The sensor detects formaldehyde in real samples.The main research contents are as follows:(1)Based on the redox peak current Ip in electrochemical scanning.A single factor experiment was used to optimize the parameters of the AuNPs@PPY/GCE sensor.The electric quantity of pyrrole polymerization during polypyrrole modification and the time of immersion of polypyrrole electrode in chloroghic acid solution during modification of gold nanoparticles were optimized.When the electric quantity reaches 0.001 C when pyrrole is polymerized and the PPy/GCE sensor is soaked in chlorofluorocarbon solution for 100 min,the response signal of the final AuNPs@PPy/GCE sensor can reach the best.By physical characterization of the sensors obtained in each stage of the AuNPs@PPy/GCE sensor preparation process,it can be found that each has its own unique physical characteristics.Through electrochemical characterization,it can be found that the conductivity increases gradually and the necessity of large overpotential treatment is also demonstrated.(2)dynamic process of formaldehyde catalyzed by AuNPs@PPY/GCE sensors was explored by cyclic voltammetry.AuNPs@PPy/GCE sensor used differential pulse voltammetry for formaldehyde detection,the optimized parameters was obtained:the initial potential was-0.9v,the termination potential was-0.lv,the standing time was 0min,and the deposition time was 120s.Under the best parameters AuNPs@PPy/GCE sensor detects formaldehyde,formaldehyde concentration shows a good linear relationship with the peak current,and R2=0.997,the detection limit is 20μmol/L.AuNPs@PPy/GCE sensor has good characteristics for formaldehyde detection.Methanol,formic acid,5-hydroxymethylfurfural,anti-2,4-decadienal,and n-nonaldehyde do not strongly interfere with the detection of formaldehyde by this sensor.The relative standard deviation(RSD)of five AuNPs@PPy/GCE sensors with the same modification conditions for the detection of 3.3 mmol/L formaldehyde was 4.7%.The detection of 3.3 mmol/L formaldehyde by AuNPs@PPy/GCE sensor is still 84%of the initial value after 20 days of nitrogen filling in 4℃.Compared with other electrochemical analysis techniques,this method has a relatively simple sensor preparation method and a relatively low detection limit.(3)Formaldehyde in milk was detected by AuNPs@PPy/GCE sensor.The linear relationship between the concentration of formaldehyde in milk and the peak current measured by differential pulsed voltammetry was obtained,and R2=0.991.The detection limit was 0.4 mmol/L.