...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Environmental Science & Technology >Unveiling New Degradation Intermediates/pathways From The Photocatalytic Degradation Of Microcystin-lr
【24h】

Unveiling New Degradation Intermediates/pathways From The Photocatalytic Degradation Of Microcystin-lr

机译：从微囊藻毒素-lr的光催化降解中揭示新的降解中间体/途径

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Mass spectrometry was utilized for structural identification of the intermediates formed during the photocatalytic degradation of the cyanotoxin, microcystin-LR with immobilized TiO_2 photocatalysts at neutral pH. Most of the intermediates reported herein have not been found in prior studies. Results indicate that MC-LR degradation is initiated at four sites of the toxin; three on the Adda amino acid (aromatic ring, methoxy group, and conjugated double bonds) and one on the cyclic structure (Mdha amino acid). Several intermediates gave multiple peaks in the TIC (m/z = 1011.5,1029.5,1063.5), which were deduced to be geometrical or constitutional isomers. This is the first study that reports the hydroxylation of the aromatic ring and the demethoxylation of MC-LR with TiO_2 photocatalysis. The most targeted site was the conjugated diene bonds because of their location in the MC-LR structure. Isomerization at the C_4-C_5 and C_6-C_7 of the diene bond of the Adda chain was a direct result of hydroxyl radical addition/substitution. Based on the above, we concluded that oxidation and isomerization of the diene bonds of MC-LR occurred simultaneously. Other steps included hydroxyl substitution, further oxidation, and bond cleavage. As the reaction time progressed, simultaneous oxidation of the Adda chain and the cyclic structure occurred.
机译：质谱用于在中性pH下用固定化的TiO_2光催化剂对氰毒素微囊藻毒素-LR进行光催化降解过程中形成的中间体的结构鉴定。本文报道的大多数中间体尚未在先前的研究中发现。结果表明，MC-LR降解是在毒素的四个位点开始的。三个在Adda氨基酸上（芳香环，甲氧基和共轭双键），一个在环状结构上（Mdha氨基酸）。几种中间体在TIC中给出了多个峰（m / z = 1011.5,1029.5,1063.5），据推测是几何或结构异构体。这是第一个报道芳香环羟基化和TiO_2光催化作用的MC-LR脱甲氧基化的研究。最具针对性的位点是共轭二烯键，因为它们位于MC-LR结构中。 Adda链的二烯键在C_4-C_5和C_6-C_7处的异构化是羟基自由基加成/取代的直接结果。基于上述，我们得出结论，MC-LR的二烯键同时发生氧化和异构化。其他步骤包括羟基取代，进一步氧化和键裂解。随着反应时间的进行，Adda链和环状结构同时发生氧化。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号