Low-temperature conversion and determination method of chlorine isotopes in chloro herbicide

Abstract

The invention discloses a low-temperature conversion and determination method of chlorine isotopes in chloro herbicide. The method comprises the following steps: A, dechlorinating the chloro herbicide at low temperature; A-1, feeding pure water into a closed reaction vessel, and injecting the chloro herbicide to be below the liquid surface, and radiating the liquid by utilizing high-energy ultraviolet light; A-2, adding ferrous sulfate powder and hydrogen peroxide; A-3, placing the reaction vessel in an ultrasonic instrument to have ultrasonic reaction for 5h to 10h in the temperature range of 80 to 100 DEG C; A-4, placing the reaction vessel in the strong ultraviolet light to be radiated for 3h; B, extracting and purifying inorganic chlorine; C, ion exchanging preparation and thermo ionization mass spectrum determination and correction: C-1, coating the graphite of a thermo ionization mass spectrum instrument with the high-purity cesium chloride solution obtained in the previous step, carrying out the thermo ionization mass spectrum testing, simultaneously receiving the intensity of ion peaks with m / e of 301 and 303 by utilizing a faraday cup, and obtaining a final theta 37Cl' value through calculation. By adopting the method, the chloro herbicide can be high-efficiently converted and purified under low-temperature condition, and finally a constant value of the isotope of organic monomer chlorine can be conveniently realized.

Description

technical field [0001] The invention relates to a method for testing, comparing and correcting chlorine isotopes in chlorinated herbicides, which belongs to the category of organic monomer isotope analysis technology (CSIA), and can be applied to the fields of environmental protection, geology, food, medicine and the like. Background technique [0002] With the continuous deepening of environmental science, earth science, food science and medical research, the new organic monomer isotope technology (CSIA) has become a frontier research hotspot. The use of organic monomer isotope technology (CSIA) can identify and track the source of organic pollution, evaluate the degradation process of organic pollutants and test the effect of control measures, identify the source of major diseases, etc. Chlorinated herbicides (such as 2,4-D) are common pollutants in the environment, and it is of great practical significance to develop a test method for its monomer isotope first. [0003] ...

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Problems solved by technology

[0003] Current methods for analyzing isotopes of organic monomers include gas chromatography quadrupole mass spectrometry (GC / qMS), gas chromatography-isotope ratio mass spectrometry (GC / IRMS), thermal ionization mass spectrometry (TIMS), etc. It has special properties, it has strong non-volatility and strong hydrophilicity, and it is difficult to use the above-mentioned instruments for isotope analysis. Therefore, there have been no literature reports on the determination of chlorine isotopes in chlorinated herbicides.

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