School of Earth Sciences, 125 South Oval Mall, The Ohio State University , Columbus, Ohio 43210, USA.
J Agric Food Chem. 2012 Oct 3;60(39):9801-6. doi: 10.1021/jf302564d. Epub 2012 Sep 24.
Ormetoprim (OMP) is an antibiotic approved for use in the United States to prevent the spread of disease in freshwater aquaculture. It has been shown in the previous literature to be photochemically stable to direct photolysis, but the role of photosensitization processes in the presence of dissolved organic matter (DOM) on the rate of degradation is not well understood. The present results show that water and DOM (specifically the fulvic acid fraction) isolated from a eutrophic aquaculture catfish pond and a nearby stream (Deer Creek) at the Mississippi State University Delta Research and Extension Center facility in Stoneville, MS, significantly increased the phototransformation of OMP relative to direct photolysis. Similar results were reported for reference fulvic acids obtained from the International Humic Substances Society. Results from a combination of scavenging experiments and experiments conducted under anoxic conditions indicate the indirect photodegradation pathway occurs by hydroxyl radical, singlet oxygen attack, and reaction with triplet excited-state DOM.
奥莫匹星（OMP）是一种在美国获得批准使用的抗生素，用于预防淡水水产养殖中的疾病传播。先前的文献表明，它在直接光解下具有光化学稳定性，但在溶解有机物（DOM）存在的情况下，光敏化过程对降解速率的影响尚不清楚。目前的结果表明，来自密西西比州立大学三角洲研究与推广中心水产养殖鲶鱼池塘和附近溪流（鹿溪）的水和 DOM（特别是富里酸部分）显著增加了奥莫匹星的光转化，与直接光解相比，这一过程相对更快。从国际腐殖质协会获得的参考富里酸也报告了类似的结果。清除实验和缺氧条件下进行的实验的结果表明，间接光降解途径是通过羟基自由基、单线态氧攻击和与三重激发态 DOM 的反应发生的。
