Chemical Alterations of Dissolved Organic Matter by Permanganate Oxidation.
Chemical Alterations of Dissolved Organic Matter by Permanganate Oxidation.
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DOI：
10.1021/acs.est.9b06675
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发表时间：
2020-02
影响因子：
11.4
通讯作者：
Juliana R. Laszakovits;Á. Somogyi;A. MacKay
中科院分区：
文献类型：
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作者：
Juliana R. Laszakovits;Á. Somogyi;A. MacKay
溶解性有机物（DOM）是饮用水中普遍存在的物质，能有效地去除高锰酸盐等氧化剂。在这里，在典型的饮用水处理条件下（6 µM，1小时），高锰酸盐氧化诱导DOM的变化，以散装DOM的性质，DOM官能团，DOM化学式进行了检查两种DOM分离类型（陆地和微生物）。过氧化物氧化没有矿化DOM，而变化的组成性质。光学性质表明，高锰酸盐氧化降低DOM的芳香性（降低苏瓦-254），降低DOM的电子给能力，并降低DOM的平均分子量（增加E2/E3比值）。傅立叶变换红外光谱二阶导数分析表明，高锰酸盐不氧化DOM烯烃基团，这表明高锰酸盐访问功能基团可能是重要的。四种离子化技术用于高分辨质谱：负离子和正离子模式电喷雾离子化和负离子和正离子模式激光/解吸离子化。将所有四种技术的结果结合起来，以了解DOM化学式的变化。高锰酸盐氧化含氮芳香族化合物和烷基苯生成含氮脂肪族化合物和含苯甲酸化合物。这项工作突出了如何多重电离技术与UHR-MS可以使DOM的更详细的表征。
Dissolved organic matter (DOM) is ubiquitous in raw drinking water and can efficiently scavenge oxidants, such as permanganate. Here, changes to DOM induced by permanganate oxidation under typical drinking water treatment conditions (6 µM, 1 hr) to bulk DOM properties, DOM functional groups, and DOM chemical formulae were examined for two DOM isolate types (terrestrial and microbial). Permanganate oxidation did not mineralize DOM, rather changes were compositional in nature. Optical properties suggest that permanganate oxidation decreased DOM aromaticity (decreased SUVA-254), decreased DOM electron donating capacity, and decreased DOM average molecular weight (increased E2/E3 ratios). Fourier transform-infrared spectroscopy second derivative analyses revealed that permanganate does not oxidize DOM alkene groups, suggesting permanganate access to functional groups may be important. Four ionization techniques were used with ultrahigh resolution mass spectrometry: negative and positive ion mode electrospray ionization and negative and positive ion mode laser/desorption ionization. The results from all four techniques were combined to understand changes in DOM chemical formulae. It was concluded that nitrogen-containing aromatic compounds and alkylbenzenes were oxidized by permanganate to form nitrogen-containing aliphatic compounds and benzoic acid-containing compounds. This work highlights how multiple ionization techniques coupled with UHR-MS can enable a more detailed characterization of DOM.