Study On Residue And Environmental Behavior Of The Herbicide Flumioxazin

Flumioxazin is part of the N-phenylphthalimide class of herbicides,developed by Japan Sumitomo Chemical Industry Co.Ltd.It is a broad-spectrum contact herbicide and use to control the susceptible broadleaf weeds and grasses in wheat,soybean and peanut,etc.Flumioxazin has been used over the world.Despite flumioxazin plays a positive role in agricultural production,it has risks to environment and human.Flumioxazin has acute and chronic toxic effects on non-target species.So,it has great significance to determine the presence and concentration of flumioxazin in crops and environment to reduce the risks to human and environment.Firstly,A rapid,simple,sensitive and effective analytical method for determination of flumioxazin in food(apple,grape,wheat,soybean,cabbage,and orange),soil and water based on a QuEChERS procedure was developed using HPLC-MS/MS.The samples were extracted with acetonitrile and cleaned-up by dSPE.The sample analysis of the total time was below 5 min and the retention times of flumioxazin was 2.37 min by using an Eclipse Plus C18 column connected to an electrospray ionization source in positive mode(ESI+).The sensitivity,accuracy and precision of the method can meet the requirements of the experiment.Secondly,the photolytic and hydrolytic properties of flumioxazin under different conditions were investigated using the indoor simulation test method.The results showed that the hydrolysis half-life of flumioxazin was 63.00,33.00 and 28.50 h in the buffer solutions with the initial concentration of 2 mg/L at p H,5,7 and 9,respectively.The degradation was much faster in alkaline solutions than in the neutral and acidic solutions.The hydrolysis half-lives of flumioxazin was 33.00,23.10 and 8.88 h in the buffer solutions with the initial concentration of 2 mg/L at pH 7,15,25 and 35c?.The higher the temperature,the faster the hydrolysis rate.The hydrolysis rate of fulmioxazin in river water is higher than that in tap water and distilled water.Under the irradiation of 300 W mercury lamp,the photolysis rate of flumioxazin was higher than that under the acidic and neutral conditions.The photolytic rates of flumioxazin in different organic solvents showed the following sequence: methanol>ethyl acetate>N-hexane> acetonitrile > acetone.The photolysis rate under different light sources followed the sequence: 500 W mercury lamp>300 W mercury lamp>xenon lamp.The results provided a scientific basic for environmental risk assessment of flumioxazin.Thirdly,the residue and degradation dynamics of 480g/L flumioxazin Suspension agent in soybean and soil were studied in three places for two years.The degradation dynamic curve in soybean plants can not fit,because the original deposition amount is low.In 2016 and 2017,the half-lives for the dissipation of flumioxazin in soil(Shen Yang)was 23.89 and 19.25 d.The degradation curves in Shandong and Shenyang cannot be fitted.In the final residue test,all the samples were not detected.The results of the paper are of great significance to the scientific use of pesticides,to reduce the pollution of the environment and to the harmfulness of nontarget organisms.