Degradation Mechanism of Cyanobacterial Toxin Cylindrospermopsin by Hydroxyl Radicals in Homogeneous UV/H2O2 Process
Degradation Mechanism of Cyanobacterial Toxin Cylindrospermopsin by Hydroxyl Radicals in Homogeneous UV/H2O2 Process
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DOI：
10.1021/es403732s
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发表时间：
2014-04-15
影响因子：
11.4
通讯作者：
Dionysiou, Dionysios D.
中科院分区：
文献类型：
--
作者：
He, Xuexiang;Zhang, Geshan;Dionysiou, Dionysios D.
柱孢菌素（CYN），一种广泛分布的高毒性蓝藻毒素（蓝藻毒素）的降解仍然很难阐明。采用质谱技术研究了UV-254 nm/H2 O2高级氧化法（AOP）对氰氮的降解机理。鉴定的各种副产物表明三种常见的反应途径：羟基加成（+16 Da）、醇氧化或脱氢（-2 Da）和硫酸根消除（-80 Da）。在羟甲基尿嘧啶和三环胍基团处观察到降解的起始;在延长的反应时间或更高的UV能量密度下也注意到尿嘧啶部分裂解/断裂和生物碱的进一步开环。使用天然水基质，CYN的降解速率降低，检测到较少的副产物（物种）;然而，CYN在延长的UV照射下被有效地消除。本研究证明了CYN降解的效率，并提供了一个更好的理解CYN降解的羟基自由基，活性氧物种，可以产生的大多数高级氧化物，并存在于自然水环境中的机制。
The degradation of cylindrospermopsin (CYN), a widely distributed and highly toxic cyanobacterial toxin (cyanotoxin), remains poorly elucidated. In this study, the mechanism of CYN destruction by UV-254 nm/H2O2 advanced oxidation process (AOP) was investigated by mass spectrometry. Various byproducts identified indicated three common reaction pathways: hydroxyl addition (+16 Da), alcoholic oxidation or dehydrogenation (-2 Da), and elimination of sulfate (-80 Da). The initiation of the degradation was observed at the hydroxymethyl uracil and tricyclic guanidine groups; uracil moiety cleavage/fragmentation and further ring-opening of the alkaloid were also noted at an extended reaction time or higher UV fluence. The degradation rates of CYN decreased and less byproducts (species) were detected using natural water matrices; however, CYN was effectively eliminated under extended UV irradiation. This study demonstrates the efficiency of CYN degradation and provides a better understanding of the mechanism of CYN degradation by hydroxyl radical, a reactive oxygen species that can be generated by most AOPs and is present in natural water environment.