Terahertz Spectroscopic Investigation Of Plant Growth Regulators

Plant growth regulators is one of synthetic organic compounds which have a significant control effect to the growth and development of vegetable crops with natural plant hormone activity. Although is belong to pesticide and have threat to livestock and environment when it excessive residual, the research and application of plant growth regulators had already regarded as the main measure to achieve the over fulfil a production target in agricultural in the21st century no matter domestic and overseas. So that’s why we are not only pay close attention to the function of plant growth regulators but also care the virulence and vestigial. The main detection principle to test plant growth regulators is chromatography, but the qualitative ability of chromatography is instability. Usually, the qualitative results need to compare with sterling determinand or the related chromatographic qualitative data.Terahertz radiation has lots of specific features, such as macromolecule skeletal vibration, molecular interactions and the vibration of the dipole. As obtain abundant spectral information, terahertz is expected to become the effective method to measure the vestigital of plant growth regulators. This essay is force on terahertz spectrum detection of plant growth regulators and analyse. All the content indicates below:Chapter one introduce the the characteristics and the detection method of plant growth regulators. The characteristics of terahertz radiation and several commonly used THz generation and detection methods were introduced.And then introduce present research status in china.Chapter two introduce transmission-type THz time domain spectroscopy (THz-TDS) system. And introduce how to extract THz optical properties, include both solid and liquid samples’ refractive index and absorption coefficient. Show the fundamental principle unary linear regression method. Chapter three obtain that6-Benzylaminopurine、Sodium p-Chlorophenoxyacetate、 forchlorfenuron、thidiazuron and sodium2-nitrophenolate has an obvious characteristic absorption peak at Terahertz band. Also prove THz-TDS is a useful method to measure elaborate material structure that has an obvious test result between in neighbouring nitrophenol sodium and Sodium para-nitrophenolate.Chapter four show the fundamental principle unary linear regression method(SLR). After the qualitative analysis of ten plant growth regulators by THz-TDS method, do a spectral measurement of sodium2-nitrophenolate and Sodium para-nitrophenolate. The test results indicate the absorption coefficient and refractive index grow with the rise of percent concentration. All of these tests indicate THz-TDS system have a great potential in quantitative detection levels. At last simulate their linear relation between absorption coefficient and the mass fraction. However, the test results indicate that the absorption coefficient reduce by the increasing concentration of sodium para-nitrophenolate liquor. Because with the increase of concentration, polarity is become more and more weak and the absorption coefficient of terahertz reduced.Chapter five optimizing the absorption spectrum of all the five plant growth regulators mention which have absorption peak at the terahertz band. As the absorption peak become more prominent and sharp after majorization, and comparative more apparent. And then use Gaussian03to simulate a absorb simulation of the five plant growth regulators mentioned above that apply the B3LYP of DFT (Density Functional Theory). Most of the absorption peaks are identical the test results, but sometimes will excursively a bit. At last analyse the reason of generate absorption peak and give a description of why excursion.At the end of this report, do a conclusion of the research and also discuss the further work.