Study On Electrochemical Behaviors Of Several Nitrobenzene Pesticides

Electrochemical analysis method has high sensitivity, good selectivity,determination of rapid accurate, easy operation etc., there is a very important theoretical significance and application value in studying the pesticide residue. Direct electrochemical detection of pesticide with the electricity active group has the gradually become hot topics in the study of pesticide residue detection method. The nitro of nitrobenzene compounds is easily reduced, the researchers usually using electrochemical method to study the reduction peaks of the reaction to form and implement residue detection.1. Using the properties of the nitro of nitrobenzene compounds, we studied the electrochemical properties of pendimethalin by cyclic voltammetry and differential pulse voltammetry, and the for experimental conditions were optimized. In a supporting electrolyte of B-R of p H 6.10, cyclic voltammetry has been used, pendimethalin gives an obvious reductive peak which potential was-0.61 V and a asymmetric oxidation peak which potential was 0.27 V. Using differential pulse voltammetry to do quantitative research through Compared two peak of pendimethalin, we found that the oxidation peak is better than reducing peak, it's higher sensitivity and more stable. The peak current and the concentration of pendimethalin in the 0.1mg/L~20mg/L showed a good linear relationship.Linear equation: IP(?A)=0.50255c(mg/L)+1.0267, R2 = 0.9969, and the detection limit is0.05mg/L. Similarly, we studied trifluralin, fomesafen, oxyfluorfen respectively, and the experimental conditions were optimized. In a supporting electrolyte of Phosphate buffer of p H 6.98, trifluralin gives the best oxidation peak. The peak current and the concentration of trifluralin in the 0.5mg/L~10mg/L showed a good linear relationship. Linear equation:IP(?A)=0.80583c(mg/L)+1.1184, R2=0.9948, and the detection limit is 0.3mg/L. In a supporting electrolyte of B-R of p H 4.10, fomesafen gives the best oxidation peak. The peak current and the concentration of fomesafen in the 0.1mg/L~5mg/L showed a good linear relationship. Linear equation: IP(?A)= 1.3247c(mg/L)+0.88828,R2=0.9993, and the detection limit is 0.05mg/L. In a supporting electrolyte of B-R of p H 6.10, oxyfluorfen gives the best oxidation peak. The peak current and the concentration of fomesafen in the1mg/L~15mg/L showed a good linear relationship. Linear equation: IP(?A) = 0.63557c(mg/L) + 0.49527, R2 = 0.9999, and the detection limit is 0.05mg/L.2. In the first part of the experiment, we found that pendimethalin and oxyfluorfen optimal detection conditions are similar, and the oxidation peak potential difference appears relatively large, we did same research to detect them at the same time. Experiments show that the oxidation peak almost same as the single detection. They can be measured at the same time. Adding different concentrations of oxyfluorfen in pendimethalin solution of2mg/L, we found oxidation peak current and the concentration of oxyfluorfen in the1~15mg/L show a good linear relationship. Linear equation: IP(?A)=0.62286c(mg/L)+0.76114, R2= 0.9989. The detection limit was 0.05mg/L. Adding different concentrations of pendimethalin in oxyfluorfen solution of 2mg/L, we found oxidation peak current and the concentration of pendimethalin in the 0.2~20mg/L show a good linear relationship.Linear equation: IP(?A) =0.53231c(mg/L) + 0.98129, R2 = 0.9949. The detection limit of0.1 mg/L.3. The glassy carbon electrode scanned by cyclic voltammetry in-0.8 V~2.4 V voltage range in the furfural solution, formation of polyfurfural film/GCE. Using differential pulse voltammetry in fomesafen solution, compared to the same concentration bare glassy carbon electrode scan results, we found that the oxidation peak was significantly enlarged in the polyfurfural film/GCE electrode. Indicating that the polyfurfural film reacts the fomesafen catalyst.