Adsorption And Hydrolysis Behavior Of Three Kinds Of Neonicotinoid Insecticide On Soil

In order to detect the residues of dinotefuran, imidacloprid and acetamiprid in the rice fields, timely and accurately evaluate their ecological environment, guide theirsecurity applic ation, the way to simultaneously determinate their residues have been studied. Additional, other studies including their adsorption and hydrolysis behavior and the relative effect factors, such as different type and dosage of biological carbon. These research not only assist to evaluate their effect on ecological environment, but also provides a new thought to renovate soil polluted by esticide. The main contents of the paper and the results are as follows:(1) The residue detecting method of dinotefuran, imidacloprid and acetamiprid in paddy water, paddy soil, rice plant, rice stem, hull and brown rice has been established by high performance liquid chromatograph with ultraviolet detector. The samples were extracted with acetonitrile, except rice samples were extracted with a mixture of acetonitrile and water(1:1,V/V). They were cleaned-up with Florisil columns except paddy water, and determined by high performance liquid chromatograph with ultraviolet detector, methanol and water(30:70, V/V) was used as mobile phase at graded flow rate, and ultraviolet absorption wavelength was set at 254 nm. With fortified concentration range of 0.05-2 mg/kg, the average recoveries of samples ranged from 81%to 99%, and with relative standard deviation (RSD, n= 5) of 1.2%-7.9%. Pre-treatment process of the method was relatively simple, and the sensitivity and accuracy of the method meet with the technical requirement for the analysis and detection of pesticide residues.(2) The paper systematically research the adsorption behavior, mechanism and effect factors of dinotefuran, imidacloprid and acetamiprid in two species soil; results showed that the output fits to Freundlich model, related coefficient reachs 0.9014 above, reached significantly level; the adsorption capacity order of soil on three species pesticide followed by imidacloprid, acetamiprid, dinotefuran; The adsorption capacity of Hunan tide soil is stronger than Hunan red on these three species pesticide.(3) Paper researched adsorption effect of soil with different biological carbon improved based on above test condition; results showed that, the soil assists to adsorption greatly; The soil with low temperature biological carbon owns stronger adsorption capacity than high temperature biological carbon on these hydrophilic pesticides; Hunan red soil after biological carbon improved owns stronger adsorption capacity than Hunan tide soil on three species pesticide.(4)The indoor simulation experiment detetes the effect of pH value and temperature on hydrolysis of dinotefuran, imidacloprid or acetamiprid. Results showed that the hydrolysis of dinotefuran, and imidacloprid or acetamiprid belongs to alkaline hydrolysis, their hydrolysis rate speed up as temperatures rising.