Malouki Moulay A, Lavédrine Bernadette, Richard Claire
Laboratoire de Photochimie Moléculaire et Macromoléculaire, UMR n 6505 CNRS, Université Blaise Pascal, F-63177 Aubière Cedex, France.
Chemosphere. 2005 Sep;60(11):1523-9. doi: 10.1016/j.chemosphere.2005.02.080. Epub 2005 Apr 18.
The influence of nitrate and nitrite ions on the degradation of methabenzthiazuron upon irradiation using artificial solar light has been investigated. The rate of degradation of methabenzthiazuron (1 microM) was accelerated by NO3- (0.1 mM) by a factor of 10. The irradiation of methabenzthiazuron (0.1 mM) in the presence of NO3- (1 mM) or NO2- (0.1 mM) yielded numerous intermediary photoproducts. Mineralization was achieved after prolonged exposure. Some were identified with the help of LC-ESI-MS and flow injection APCI-MS techniques. Both oxidations of the aromatic ring and of the urea chain were observed. The former started by hydroxylation of the ring. Further oxidation of the ring led to cleavage of the benzenic ring with formation of dialdehydic, diacidic and anhydric compounds. Complete removal of the lateral urea chain took place subsequently to demethylation of the terminal methyl group and loss of the CO-NH2 group. Nitration was a minor process. This work shows that the photodegradation of methabenzthiazuron in the presence of nitrate or nitrite ions is highly non-specific.
研究了硝酸根离子和亚硝酸根离子对使用人工太阳光照射下甲苄噻隆降解的影响。硝酸根离子（0.1 mM）使甲苄噻隆（1 microM）的降解速率加快了10倍。在硝酸根离子（1 mM）或亚硝酸根离子（0.1 mM）存在下照射甲苄噻隆（0.1 mM）产生了许多中间光产物。长时间照射后实现了矿化。借助液相色谱-电喷雾电离质谱（LC-ESI-MS）和流动注射大气压化学电离质谱（flow injection APCI-MS）技术鉴定了其中一些产物。观察到芳环和脲链均发生氧化。前者始于环的羟基化。环的进一步氧化导致苯环断裂，形成二醛、二酸和酸酐类化合物。末端甲基脱甲基化和CO-NH2基团丢失后，侧链脲链完全去除。硝化作用是一个次要过程。这项工作表明，在硝酸根或亚硝酸根离子存在下甲苄噻隆的光降解具有高度非特异性。
