Study On Polymorphism And Analysis Methods Of Several Pesticides

The appearance of drug polymorphs depends on the molecular structure and the crystallization process,which has caused widespread concern among researchers.The crystal form of the drug molecule is different,resulting in a significant difference in its physical and chemical properties,and in the field of pharmaceutical preparations,the valuable crystal forms are mostly polymorphs,solvates or salts.Secondly,the polymorphic form of the drug affects the production process to a certain extent,which has a great significance for the development of new drugs,the optimal control of ideal crystal crystallization conditions,and the patent protection of drugs.Buprofezin is a typical polymorphic drug,and there are few reports on the polymorphic forms in the literature.The study of crystallization not only provides a theoretical basis for the crystallization process of polymorphic drugs,but also provides a reference value for the industrial crystallization process.Glufosinate is a broad-spectrum,high-efficiency non-selective herbicide,and L-glufosinate is not only a new natural compound,but also more than twice as effective as glufosinate.What’s more,it has a huge space for development with its di fficult to develop resistance and longer use cycle.Therefore,how to control and monitor the concentration of L-glufosinate in the process of pesticide production effectively and effectively has received wide attention.Currently reported methods for the analysis of glufosinate and L-glufosinate,including gas chromatography,liquid chromatography,capillary electrophoresis,GC/MS,LC/MS,etc.,a more suitable method is liquid phase analysis from the physical and chemical properties of L-glufosinate.Therefore,the research content of this paper is as follows:（1）The crystal growth method selected of the buprofezin is a slow volatilization method.First,a suitable amount of the buprofezin sample is added to a certain amount of a solvent with good solubility to stirred and dissolve,and the clear saturated solution obtained by filtration is placed.The bottle is sealed with a sealing film with small holes and then allowed to stand in a fume hood for natural evaporation.Finally,the effects of single solvent,combination solvent and acid-containing solvent on the crystal form of buprofezin were investigated.The experimental results showed that the single solvent and the combined solvent had no effect on the crystal form of buprofezin,and the obtained crystal forms were all polymorphⅠof compound 1.PolymorphⅡand compounds 2 and 3 were acquirred in an acid-containing solvent,respectively.（2）Using a variety of characterization methods,such as single crystal X-ray diffraction,X-ray powder X-ray diffraction,Hirshfeld surface analysis,differential scanning calorimetry,thermogravimetric analysis,Fourier infrared spectroscopy and Raman spectroscopy to characterized the crystal forms of buprofezin,and then screened to investigate the molecular structure and thermal stability of the polymorph.（3）The analytical detection method of L-glufosinate,the ultraviolet spectrophotometer is used for full-wavelength scanning,195 nm is selected as the detection wavelength,and then analyzed by high performance liquid chromatography.experimental conditions:column,C18,250 mm×4.6 mm,5μm;mobile phase,acetonitrile+water=120:880（v/v）,5.75 g NH₄H₂PO₄,10 mL 10%tetrabutylammonium hydroxide,50%phosphoric acid adjusted to pH 3.6;flow rate,1.0 mL/min;detection wavelength,195 nm;column temperature,25°C;injection volume,20μL.The experimental results of quantitative analysis and qualitative analysis showed that the analytical method is simple,rapid and correct.It is an ideal analytical method for detecting L-glufosinate.