微囊藻毒素-RR的提取和臭氧氧化降解

在对采自云南滇池水华蓝藻细胞中的微囊藻毒素-RR(microcystin-RR,MC-RR)提取并发现其含量达到0.19mg/g(干重)的基础上,重点研究了臭氧氧化降解所提取的MC-RR。结果表明,当反应体系中臭氧浓度为5.7 mg/L时,初始浓度1.9 mg/L的MC-RR在15 min内被完全降解。利用HPLC/ESI/MS对提取的MC-RR及其氧化降解产物质荷比测定发现,降解前MC-RR的质谱图中出现特征离子m/z=1 038.7、m/z=519.8以及m/z=135.0。而降解后的产物质谱图中只有Adda基团中带苯环结构化合物(C9H10O)的特征离子峰m/z=135.0存在,其他2个离子峰完全消失。由此推断反应体系中MC-RR(m/z=1 038.2)在大量臭氧及其.OH自由基全面攻击下,分子结构中Adda基团以及单环结构中的不饱和双键直接被氧化而发生断链,最终形成小分子的有机物。

Extraction and ozonation of microcystin-RR from cyanobacterial blooms

Microcystin-RR(MC-RR) was successfully extracted from cyanobacterial cells collected from Dianchi Lake and its content in cyanobacteria samples was determined to be at least 0.19 mg/g(dry weight).Ozone was applied to degrade MC-RR extracted.The results showed that initial 1.9 mg/L MC-RR was completely degraded by ozone within 15 minutes when the O3 concentration in reaction system reached 5.7 mg/L at room temperature.The HPLC/ESI/MS analysis on MC-RR and its oxidative degradation products demonstrated that the parent ion m/z=1 038.7,ion m/z=519.8 and m/z=135.0 which represent MC-RR were obviously appeared while both of ion m/z=1 038.7 and ion m/z=519.8 were not found on the MS profiles of its oxidative degradation products.Ion m/z=135.0 which represents the compound(C9H10O) with aromatic ring contained in Adda remained unchanged.These provided the positive evidences that MC-RR was degraded completely into small molecule organic compounds for its unsaturated double bond sites cleaved by a large number of ozone and ·OH in reaction system.