As we all know, pesticides are a class of toxic fine chemicals. Its toxicity mainly comes from pesticide precursors, impurities, metabolites and surfactants added in pesticide processing. Therefore, the registration and management of pesticides in countries and organizations around the world are quite strict. Since the restoration of pesticide management institutions in China in the 1980s, after more than a decade of development, its pesticide registration system has gradually been in line with international standards, and higher requirements have been placed on the registration of pesticides. In addition to completing various toxicity tests for pesticides, it must be Provincial and above, accredited laboratories provide the names and content ranges of the components (active ingredients, impurities, solvents, moisture, etc.) that make up the pesticide product. If the impurity content is above 0.1%, the qualitative map and structural formula must be provided. Quantitative analysis methods, etc. That is to say, the full analysis of pesticides in the full analysis of pesticides aims to clarify the components of pesticides and reduce their potential harm to the environment; It also helps the production enterprises to improve the synthetic process, improve the yield and product quality, and enhance the market competitiveness.
China's pesticide analysis and research work is relatively late. In addition to the late formulation of regulations, the lack of instruments is also one of the constraints. everybody knows. Among the commercially available pesticides, a considerable part of the varieties cannot be vaporized or thermally unstable, such as phenylureas and sulfonylureas. These varieties are analyzed by liquid chromatography. In the past, column separation and preparation were usually used. The method is full analysis, but some components are low in content, making it difficult to prepare standard products. It is impossible to carry out structural identification. In recent years, with the gradual popularization of HPLG-MS, the research on the above pesticide varieties has been realized. Combining the production process and using HPLC /MS to identify and quantify the pesticide components, the operation is simple, fast and accurate.
We used HPLC/MS to conduct a full analysis of several pesticide varieties. The analysis results of the main impurities in the sulfonylurea herbicide methylsulfuron industrial products are summarized as follows.
1 instruments and reagents Agilent 1100 HPLC-MS system. Online degasser, quaternary gradient pump, autosampler, enthalpy incubator, DAD detector; all reagents are HFLC grade (Fischer), water is re-distilled and filtered through 0.45μm membrane. Metsulfuron industrial products: ≥95%
2 High Performance Liquid Chromatography / Mass Spectrometry Condition Chromatography: Zolbbax: SB-C18, 2.1 mm x 150 mm; ionization mode: AP1-ES (POS); mobile phase: 65% acetonitrile / 35% water (pH 3.0 acetic acid adjustment) ); flow rate: O. 2 ml/min; CID voltage: 60 V; detection wavelength: 254 tim; drying gas: 10 L/min. Drying gas temperature 300 ° C; atomizing gas pressure: 40 psi;
3 Analysis results Under the above conditions, metsulfuron-methyl and its main impurities can be well separated. Due to the high degree of vacancy, we did not collect the signal of the main peak. The corresponding liquid chromatogram and mass spectrometer total ion flow diagram are shown in Figure 1 and Figure 2. The variety is prepared by reacting 2-amino-4-methoxy-6-methyl-s-triazine with methyl 2-methyl benzenesulfonyl isocyanate, and impurity 1 is an unreacted intermediate triazineamine impurity 2 The molecular weight of the main product differs by a factor of 14. From the product structure, it is easy to infer that the impurity 2 is the corresponding acid formed by hydrolysis of the main product. According to the fragmentation and quality information, combined with the preparation process, the impurity 3 is the 2-methylester benzenesulfonamide formed by the esterification of the saccharin after the ring opening. We have carried out a full analysis of more than ten pesticides by HPLC-MS, and achieved good results. The mass spectrometry parameters such as dry gas flow rate, temperature, atomizing gas pressure and CID voltage were studied in ionization of all varieties. All of the impurities listed in the text are determined by the mass spectrometry. All impurities determined by mass spectrometry are retained by liquid chromatography when the corresponding standard is synthesized. It is confirmed that each impurity will change due to different synthetic routes, even the same route. In different factories, the amount or content of impurities will be different due to different management; the same variety with different sources should be fully analyzed to ensure the accuracy of the results. The molecular weight of the pesticide is small, and the large zui is generally not more than 1000. We have used single-stage quadrupole liquid chromatography-mass spectrometry to identify the unknowns in different types of varieties; The reaction was monitored, the process conditions were optimized, and the research progress was accelerated. The residual determination method of carbamate and sulfonylurea pesticides was studied. The selective ion detection was used, and the low yield of Zui was about 1Opg. Derivatization treatment, simple and easy to use results show that single-stage quadrupole liquid chromatography-mass spectrometry can fully meet the needs of pesticide research.
China's pesticide analysis and research work is relatively late. In addition to the late formulation of regulations, the lack of instruments is also one of the constraints. everybody knows. Among the commercially available pesticides, a considerable part of the varieties cannot be vaporized or thermally unstable, such as phenylureas and sulfonylureas. These varieties are analyzed by liquid chromatography. In the past, column separation and preparation were usually used. The method is full analysis, but some components are low in content, making it difficult to prepare standard products. It is impossible to carry out structural identification. In recent years, with the gradual popularization of HPLG-MS, the research on the above pesticide varieties has been realized. Combining the production process and using HPLC /MS to identify and quantify the pesticide components, the operation is simple, fast and accurate.
We used HPLC/MS to conduct a full analysis of several pesticide varieties. The analysis results of the main impurities in the sulfonylurea herbicide methylsulfuron industrial products are summarized as follows.
1 instruments and reagents Agilent 1100 HPLC-MS system. Online degasser, quaternary gradient pump, autosampler, enthalpy incubator, DAD detector; all reagents are HFLC grade (Fischer), water is re-distilled and filtered through 0.45μm membrane. Metsulfuron industrial products: ≥95%
2 High Performance Liquid Chromatography / Mass Spectrometry Condition Chromatography: Zolbbax: SB-C18, 2.1 mm x 150 mm; ionization mode: AP1-ES (POS); mobile phase: 65% acetonitrile / 35% water (pH 3.0 acetic acid adjustment) ); flow rate: O. 2 ml/min; CID voltage: 60 V; detection wavelength: 254 tim; drying gas: 10 L/min. Drying gas temperature 300 ° C; atomizing gas pressure: 40 psi;
3 Analysis results Under the above conditions, metsulfuron-methyl and its main impurities can be well separated. Due to the high degree of vacancy, we did not collect the signal of the main peak. The corresponding liquid chromatogram and mass spectrometer total ion flow diagram are shown in Figure 1 and Figure 2. The variety is prepared by reacting 2-amino-4-methoxy-6-methyl-s-triazine with methyl 2-methyl benzenesulfonyl isocyanate, and impurity 1 is an unreacted intermediate triazineamine impurity 2 The molecular weight of the main product differs by a factor of 14. From the product structure, it is easy to infer that the impurity 2 is the corresponding acid formed by hydrolysis of the main product. According to the fragmentation and quality information, combined with the preparation process, the impurity 3 is the 2-methylester benzenesulfonamide formed by the esterification of the saccharin after the ring opening. We have carried out a full analysis of more than ten pesticides by HPLC-MS, and achieved good results. The mass spectrometry parameters such as dry gas flow rate, temperature, atomizing gas pressure and CID voltage were studied in ionization of all varieties. All of the impurities listed in the text are determined by the mass spectrometry. All impurities determined by mass spectrometry are retained by liquid chromatography when the corresponding standard is synthesized. It is confirmed that each impurity will change due to different synthetic routes, even the same route. In different factories, the amount or content of impurities will be different due to different management; the same variety with different sources should be fully analyzed to ensure the accuracy of the results. The molecular weight of the pesticide is small, and the large zui is generally not more than 1000. We have used single-stage quadrupole liquid chromatography-mass spectrometry to identify the unknowns in different types of varieties; The reaction was monitored, the process conditions were optimized, and the research progress was accelerated. The residual determination method of carbamate and sulfonylurea pesticides was studied. The selective ion detection was used, and the low yield of Zui was about 1Opg. Derivatization treatment, simple and easy to use results show that single-stage quadrupole liquid chromatography-mass spectrometry can fully meet the needs of pesticide research.
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