Studies On Photochemical Degradation Of Fenpropathrin, Bifenthrin, And Deltamethrin In Organic Solution

As bionic insecticides, which were successfully developed in 1970's, Pyrethroids feature of a varieties of advantages, such as high efficiency, long-term stability, and good compatibility with environment. These insecticides can significantly absorb visible and ultra-violet light. Photochemical degradation is the main process for Pyrethoid- degradation in natural environment. Therefore, study on the mechanism of photochemical degradation is of significant importance in environmental science.Fenpropathrin, bifenthrin, and deltamethrin were chosen in this study, which usually detected with an ultraviolet detector (UVD) after separation by high performance liquid chromatography (HPLC). Phtochemical kinetics data and spectroscopic investigation provide a green, economic, and on-line derivation technique ? hyphenated photochemical-derivation and liquid chromatography (LC), which makes several pyrethroids detected with a high sensitive fluorescence detector (FLD). With a laboratory-built photochemical device, we found that an on-line photochemical derivation device combined with HPLC with UVD, FLD, and mass spectrometry detector (MSD) is a perfect system to study the pyrethroid photochemical kinetics, identify the degradation products, and investigate the degradation mechanism.This thesis includes five chapters. The first chapter is a summary of the history , application, and research base for three pyrethroids in last 10 years. Some important research results were in chapter two, three, and four, such as the kinetics parameters for pyrethroids photochemical degradation, spectroscopic data for pyrethroids and its degrading products. Some aspects about this study has been discussed in the last part of the thesis.The achievement of this thesis are mainly three parts as following:(1) The experimental used in the study is an on-line system which combined the photochemical degradation with a commercial HPLC. The good reproducibility of this system makes the investigation efficient and effective. Also, with the help of HPLC pump the products of pyrethriods photochemical degradation can be easily...