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题名: 环丙唑醇对映体在黄粉虫体内的选择性富集及代谢研究
作者: 戴欣
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: 李建中
关键词: 环丙唑醇 ; 手性 ; 黄粉虫 ; 生物富集 ; 代谢产物,cyproconazole ; chiral ; Tenebrio molitor ; bioaccumulation ; metabolite
其他题名: Bioaccumulation and Excretion of Enantiomers of Cyproconazole in Tenebrio molitor Larvae Through Dietary Exposure
学位专业: 环境工程
中文摘要:
      在农药市场中,手性农药拥有着重要的市场地位。手性农药各对映单体具有基本相同的物理、化学性质,因此长期以来,消旋体手性农药被当作单一成分的农药看 待。随着认识水平的提升,人们发现手性农药不同的对映单体在环境中可能会表现出不同的环境行为、生物活性以及生态毒性,因此近年来,关于手性农药对映单体 层面的研究开始受到人们的重视。  本文研究了三唑类手性农药环丙唑醇在昆虫黄粉虫体内的手性富集和代谢,并且对其主要代谢产物进行了初步的鉴定,主要的研究 内容和得到的主要结果如下: 以高效液相色谱仪串联质谱仪,实现了环丙唑醇的手性分离与检测。液相色谱柱为大赛璐IC手性柱(150 mm × 4.6 mm i.d. × 5 μm, Daicel, JAPAN),在流动相比例为乙腈:水(0.05%甲酸)=60:40(V:V),流速为1 mL?min-1,柱温为常温的条件下,实现了环丙唑醇的手性分离。对映单体A、B、C、D的出峰时间分别为16.8 min,18.6 min,20.76 min和26.63 min。仪器方法的最低定量限和最低检测限分别为2.4 μg?kg-1和0.8 μg?kg-1。 环丙唑醇在黄粉虫体内的富集具有手性选择性。在暴露试验的第21 d,2.5mg?kg 1, 10 mg?kg 1以及25 mg?kg-1三个浓度组中,对映体A的EF值分别为0.384、0.367和0.321,远高于麦麸中对映体A的EF值 (0.230)。这表明环丙唑醇的A对映体在黄粉虫体内出现了显著的手性富集。而对映体D的EF值则维持在较低的水平,约为0.15,远低于麦麸中对映体 D的EF值(0.26)。这表明,黄粉虫对对映体D的清除速率较高。黄粉虫通过粪便将一部分环丙唑醇排出体外,通过对粪便中环丙唑醇的含量进行检测发现, 粪便中环丙唑醇的含量较低,约占其所摄食的麦麸中的环丙唑醇浓度的10%左右,并且粪便中环丙唑醇各对映单体的含量与其在麦麸中的含量相比没有对映体差 异。环丙唑醇在黄粉虫体内的降解符合一级动力学方程(R2=0.87),半衰期为2.02 d。 通过检测和计算黄粉虫对环丙唑醇的摄入量、排泄量以及富集量,从而求得黄粉虫对环丙唑醇的代谢量。结果表明,黄粉虫摄入的环丙唑醇有90%左右被虫体代谢 掉,只有少量富集于虫体或者通过粪便排出体外。可见生物降解是环丙唑醇在黄粉虫体内的主要清除途径。 生物降解作用会导致大量的代谢产物产生,因此通过质谱全扫描来探究环丙唑醇在黄粉虫体内的主要代谢产物。结果表明,羟基化和羧基化是环丙唑醇重要的代谢途径。
英文摘要: The development of technology and higher living standards also lead to the wider usage of pesticides in agriculture, residential and public places. Chiral pesticide makes up a significant part of the pesticide market. Widespread application of chiral pesticides results in the prescience of their residue in water, soil, plants, and organisms. The environmental behavior, biological activity, and eco-toxicity of the enantiomers of chiral pesticides are generally overlooked. Enantiomers of chiral pesticides display the same physical and chemical properties in non-chiral environment but may exhibit different characteristics in chirality environment. Therefore, accumulation and excretion of chiral pesticides on the level of enantiomers have become a recent concern of scientific research. In this paper, the enantiomeric separation, bioaccumulation, and degradation of cyproconazole in Tenebrio molitor were studied. Chiral separation was achieved by high performance liquid chromatograph (HPLC) equipped with chiral liquid chromatographic column (Daicel CHIRALPAK IC, 150 mm × 4.6 mm i.d. × 5 μm, Daicel, JAPAN). Enantiomer separation was carried out by using solvent A (0.05% formal acid in ultrapure water) and solvent B (HPLC-grade acetonitrile) with an A/B ratio of 40/60 (v/v) and at a flow rate of 1 mL/min for 30 min. The column temperature was kept at 40℃. The retention time of enantiomers A, B, C, and D was 16.8 min, 18.6 min, 20.8 min and 26.63 min respectively. A TSQ mass spectrometer (TSQ QUANTUM ACCESS MAX) equipped with an ESI ionization source was used to quantify cyproconazole enantiomers. The limits of quantification (LOQ, signal-to-noise ratio of 10) for cyproconazole was estimated to be 2.4 μg?kg-1; the limits of detection (LOD, signal-to-noise ratio of 3) for cyproconazole was 0.8 μg?kg-1. Enantio-accumulation of cyproconazole was discovered. Twenty one days after exposure, the EF values of isomer A were 0.384, 0.367 and 0.321 for exposed group 2.5 μg?kg-1, 10 μg?kg-1 and 25 μg?kg-1 respectively. They are much higher than the EF value of isomer A in wheat bran (0.230). Isomer A was enantioselectivity in mealworms. The EF value of isomer D was kept to a relatively low level (about 0.15) and was far lower than the value in wheat bran (0.26); this means that isomer D doesn’t have bioaccumulation potential. Concentration of cyproconazole in worm feces was about 10 percent of the concentration of cyproconazole in wheat bran. Elimination of cyproconazole by feces was with diastereoselectivity. The dissipations of cyproconazole stereoisomers in weal worms followed first-order kinetics (R2=0.87) with half-life of 2.02 d. Meal worm absorbed cyproconazole from wheat bran. Cyproconazole accumulated in mealworm bodies, then excreted by feces or eliminated by mealworms. Over 90% of mealworm cyproconazole intake was eliminated by biodegradation. Hydroxylation and carboxylation were the principal metabolic pathway for the biodegradation of cyproconazole; the major metabolite was also detected.
内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/34122
Appears in Collections:中科院环境生物技术重点实验室_学位论文

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Recommended Citation:
戴欣. 环丙唑醇对映体在黄粉虫体内的选择性富集及代谢研究[D]. 北京. 中国科学院研究生院. 2015.
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