Transformation of 17β-estradiol in humic acid solution by ε-MnO2 nanorods as probed by high-resolution mass spectrometry combined with (13)C labeling.
Transformation of 17β-estradiol in humic acid solution by ε-MnO2 nanorods as probed by high-resolution mass spectrometry combined with (13)C labeling.
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DOI：
10.1016/j.envpol.2016.04.021
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发表时间：
2016-07
影响因子：
8.9
通讯作者：
Kai Sun;Shangtao Liang;Fuxing Kang;Yanzheng Gao;Qingguo Huang
中科院分区：
文献类型：
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作者：
Kai Sun;Shangtao Liang;Fuxing Kang;Yanzheng Gao;Qingguo Huang
甾体雌激素（SEs）广泛存在于水生系统中，有可能破坏野生动物和人类的内分泌系统。本实验研究了ε- mno2纳米棒转化17β-雌二醇（E2）的性能，并系统表征了腐殖酸（HA）对反应行为的影响。采用高效粒径排斥色谱法（HPSEC）研究腐植酸分子的重构。结果表明，ε- mno2纳米材料能有效去除水溶液中的E2。HA的存在阻碍了E2的转化，增强了E2与腐殖质分子的交叉偶联。特别地，我们使用未标记的E2和13c3标记的E2以1:1的比例（w/w）混合，通过高分辨率质谱（HRMS）探测反应产物。结合HRMS和13c3标记，发现中间产物包括雌酮（E1）、羟基化、类醌和开环种，以及E2二聚体和三聚体。更重要的是，E2和HA之间可能的交叉偶联产物也被确定。提出了双电子氧化和单电子氧化反应机理。使用HRMS和13c3标记进行反应产物鉴定的应用分析方法对于理解HA在se转化中的作用至关重要。
Steroidal estrogens (SEs), widespread in aquatic systems, have a potential to disrupt the endocrine system of wildlife species and humans. In our experiments, the performance ofε-MnO2nanorods in transforming 17β-estradiol (E2) was investigated, and the effect of humic acid (HA) on the reaction behaviors was systematically characterized. Reconfiguration of humic molecules was also investigated by high-performance size exclusion chromatography (HPSEC). Results indicated thatε-MnO2nanomaterials ensured efficient removal of E2 from the aqueous solution. The presence of HA hindered the transformation of E2, while enhanced the cross-coupling between E2 and humic molecules. In particular, we used a mixture of un-labeled E2 and13C3-labeled E2 at a 1: 1 set ratio (w/w) to probe the reaction products via high-resolution mass spectrometry (HRMS). The combination of HRMS and13C3-labeling revealed the intermediate products including estrone (E1), and hydroxylated, quinone-like, and ring-opened species, as well as E2 dimer and trimer. More importantly, possible cross-coupling products between E2 and HA were also identified. A reaction mechanism including two-electron oxidation and single-electron oxidation was proposed. The applied analytical approach using HRMS along with13C3-labeling for reaction-product identification is crucial to understanding the role of HA in the transformation of SEs.