pH 值对荧光溶解有机质光降解的影响。
Influence of pH on fluorescent dissolved organic matter photo-degradation.
机构信息
Department of Civil and Environmental Engineering, University of California, Irvine, Irvine, CA 92697-2175, USA.
University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, 146 Williams Street, Solomons, MD 20688, USA.
出版信息
Water Res. 2015 Nov 15;85:266-74. doi: 10.1016/j.watres.2015.08.047. Epub 2015 Aug 28.
A novel semi-continuous excitation emission matrix (EEM) fluorescence and absorbance monitoring system has been developed. Full EEMs were collected simultaneously with absorbance spectra every 20 min during 24 h solar-simulated irradiation experiments, and the kinetic change of fluorescence of Suwannee River natural organic matter IHSS standard material (SRNOM) at various pH values was investigated. Parallel factor analysis (PARAFAC) was then used to isolate the photo-labile and pH-influenced fluorescent components of SRNOM. Kinetic analysis showed increasing rates of fluorescence loss with increasing pH. This has significant implications for the photo-degradation of dissolved natural organic matter during estuarine mixing, when large increases of pH are common. The influence of pH on fluorescence and photo-degradation kinetics emphasizes the need for pH to be monitored and accurately controlled during laboratory experiments. It is also highly recommended that when constructing PARAFAC models or monitoring changes in fluorescence data between samples of different origins, that the pH be held constant to remove any potential artifacts or misinterpretation of data.
一种新型的半连续激发发射矩阵（EEM）荧光和吸光度监测系统已经开发出来。在 24 小时太阳模拟辐照实验中，每 20 分钟收集一次全 EEM 和吸光度光谱，研究了不同 pH 值下苏万尼河天然有机物质 IHSS 标准物质（SRNOM）的荧光动力学变化。然后使用平行因子分析（PARAFAC）分离 SRNOM 的光不稳定和 pH 影响的荧光成分。动力学分析表明，荧光损失的速率随 pH 值的增加而增加。这对河口混合过程中溶解天然有机物的光降解有重要意义，因为 pH 值会大幅增加。pH 值对荧光和光降解动力学的影响强调了在实验室实验中需要监测和准确控制 pH 值。强烈建议在构建 PARAFAC 模型或监测不同来源样品之间荧光数据的变化时，保持 pH 值恒定，以消除任何潜在的伪影或数据误判。
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