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题名: 真空紫外光电离气溶胶飞行时间质谱仪的应用研究
作者: 李娜娜
学位类别: 硕士
答辩日期: 2015-05
授予单位: 中国科学院研究生院
授予地点: 北京
导师: 束继年
关键词: 二嗪农 ; 三唑磷 ; 毒死蜱 ; NO3自由基 ; 真空紫外光电离气溶胶飞行时间质谱仪,Diazinon,triazophos,chlorpyrifos, NO3 radicals, vacuum ultraviolet photoionization aerosol time-of flight mass spectrometer
其他题名: The application of vacuum ultraviolet photoionization aerosol time-of flight mass spectrometer
学位专业: 环境工程
中文摘要:       真空紫外光电离气溶胶飞行时间质谱仪(vacuum ultraviolet photoionization aerosol time-of flight mass spectrometer,VUV-ATOFMS)是本实验室自主研制的检测有机气溶胶的仪器,可在线研究有机气溶胶的大气化学反应。本论文选取三种典型 的有机磷农药(二嗪农、三唑磷、毒死蜱)作为研究对象,采用在线的VUV-ATOFMS和离线的GC-MS两种分析仪器对其进行检测。此外,还研究了悬浮 态毒死蜱颗粒与NO3自由基的非均相反应。研究内容主要包括反应产物、反应机理和反应动力学等。结果表明,VUV-ATOFMS在有机气溶胶检测及其大气 化学反应研究方面具有独特优势。本文所得数据有助于揭示有机磷农药在大气中的化学行为及其带来的潜在危害。同时,该仪器也为有机污染物的检测提供了一项新 技术。具体研究结果如下:
      (1) 采用在线和离线两种检测方法对三种典型有机磷农药(二嗪农、三唑磷、毒死蜱)进行了对比分析。在线的VUV-ATOFMS和离线的GC-MS分析法对二嗪 农、三唑磷、毒死蜱均能成功检出。相比传统的GC-MS分析法,VUV-ATOFMS分析法无需样品前处理,大大简化了检测流程,提高了检测效率。由于 VUV软电离的优势,得到的三种物质的飞行时间质谱图均比GC-MS得到的EI质谱图碎片峰少、且丰度低,主要体现的是母离子峰。同时,对于有机磷农药而 言,化合物的主链越短,其检测出离子碎片峰越少,质谱图越简单。 
      (2) 在毒死蜱颗粒与NO3自由基非均相反应研究中,利用在线的VUV-ATOFMS结合离线的GC-MS 对非均相反应产物进行了鉴定。实验检测出毒死蜱颗粒与NO3自由基非均相反应的六种反应产物分别是chlopyrifos oxon (C9H11O4NPCl3, mol. wt. 333),3,5,6-trichloro-2-pyridinol (C5H2ONCl3, mol. wt. 197),O,O-diethyl O-hydrogen phosphorothioate (C4H11O3PS, mol. wt. 170),diethyl hydrogen phosphate (C4H11O4P, mol. wt. 154),O,O-diethyl ester thiophosphoric acid (C4H11O3PS,mol. wt. 170), bis-(1,2-ethoxycarbonylethyl)disulfide (C8H20O6P2S2, mol. wt. 338)。这些产物与其在水溶液、土壤中的降解产物有很大的差别。
      (3) 根据所确定的反应产物,以及反应物和产物质谱峰的变化,对悬浮态毒死蜱颗粒与NO3自由基非均相反应路径和机理进行了推导。毒死蜱颗粒与NO3自由基主要 通过亲电加成和水解两种方式进行反应。
      (4) 采用一种混合相相对速率法 (以异戊二烯气体为参比物),研究了悬浮态毒死蜱颗粒与NO3自由基的非均相反应速率。实验结果表明,毒死蜱颗粒与NO3自由基反应的有效速率常数为 (3.4 ± 0.2) × 10?12 cm3 molecule?1 s?1。此外,根据获得的有效反应速率常数和夜间低对流层中的NO3自由基平均浓度,推算出了悬浮态毒死蜱颗粒的大气寿命约为9.8 min。
英文摘要:       The vacuum ultraviolet photoionization aerosol time-of flight mass spectrometer (VUV-ATOFMS) is an instrument for detecting organic aerosols independently developed by our laboratory, which can study the atmospheric chemical reactions of organic aerosols online. This paper selected three typical organophosphorus pesticides (diazinon, triazophos, chlorpyrifos) as the research object, using the online and offline detection instruments to detect them. In this study, the heterogeneous reactions of chlorpyrifos with NO3 radicals are investigated. The reactions products, mechanisms and reactive rate constants are obtained in the experiments. The results show that the VUV-ATOFMS have the unique advantages in atmospheric chemistry reaction of organic aerosols. The results can shed light on understanding organophosphorous pesticides’ atmospheric behaviors and its potential harms. At the same time, it also provides a new technique in the detection of pollutants. The detailed findings are shown as follows.
      (1) Both online and offline detection methods are used to analysis three typical organophosphorus pesticides (diazinon, triazophos, chlorpyrifos). The two detection methods can successfully detect the diazinon, triazophos, chlorpyrifos. Compared with the GC-MS, the analytical method of VUV-ATOFMS requires no sample pre-treatment sample testing. Thus it can greatly simplify the testing process and improve the detection efficiency. Due to the advantages of VUV soft ionization, time-of-flight mass spectra of three materials have less and lower abundance fragments than the EI mass spectra. At the same time, organophosphorus pesticide compounds with the shorter main chain have fewer fragment ions and simpler mass spectrum.
      (2) The heterogeneous reaction of suspended chlorpyrifos particles with NO3 radicals is investigated using VUV-ATOFMS and GC-MS. Six reaction products chlopyrifos oxon (C9H11O4NPCl3, mol. wt. 333), 3,5,6-trichloro-2-pyridinol (C5H2ONCl3, mol. wt. 197), O,O-diethyl O-hydrogen phosphorothioate (C4H11O3PS, mol. wt. 170), diethyl hydrogen phosphate (C4H11O4P, mol. wt. 154), O,O-diethyl ester thiophosphoric acid (C4H11O3PS,mol. wt. 170), bis-(1,2-ethoxycarbonylethyl)disulfide (C8H20O6P2S2, mol. wt. 338) are observed, which are different from the degradation products of chlorpyrifos in water and soil.
      (3) Based on the identification of reaction products and changes of mass peaks of the reactants and products, heterogeneous reaction pathways and mechanisms of the suspended chlorpyrifos particles with NO3 radicals are derived. Hydrolysis and electrophilic additions are the main reaction mechanisms of chlorpyrifos particles with NO3 radicals.
      (4) A mixed-phase relative rate method (isoprene gas as reference material) is used to estimate the effective reaction rate of chlorpyrifos particles with NO3 radicals. Experimental results show that the effective reaction rate constant of chlorpyrifos particles with NO3 radicals is (3.4 ± 0.2) × 10-12 cm3 molecule-1 s-1. In addition, based on the obtained effective reaction rate constant and the average concentrations of NO3 radicals in low tropospheric at night, the atmospheric lifetime of the suspended chlorpyrifos particles is about 9.8 min.
内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/34498
Appears in Collections:大气环境研究室_学位论文

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Recommended Citation:
李娜娜. 真空紫外光电离气溶胶飞行时间质谱仪的应用研究[D]. 北京. 中国科学院研究生院. 2015.
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