Instituto de Química del Noroeste Argentino (INQUINOA, CONICET), Universidad Nacional de Santiago del Estero, Santiago del Estero, Argentina.
Photochem Photobiol. 2012 Jul-Aug;88(4):792-800. doi: 10.1111/j.1751-1097.2012.01135.x. Epub 2012 Mar 30.
In this study, we show that several UV-Vis absorbance, steady-state and time-resolved fluorescence parameters of a series of dissolved humic substances (DHS) from different sources (e.g. terrestrial fulvic and humic acids, and humic acid-like molecules extracted from composted and vermicomposted wastes) correlate with the molar absorptivity at 280 nm per mole of organic carbon (ε(280)), which in turn is proportional to the molecular complexity (e.g. molecular size, aromaticity and oxidation degree) of the DHS. Both absorbance and fluorescence spectral responses were sensitive to the molecular complexity associated with the maturation degree of the DHS. Depending on the DHS, different emitting responses by excitation at the UVA (340 nm) and VIS (460 nm) regions of the absorption spectra were observed. The results were explained in terms of the extent of intramolecular electronic interactions between electron donor groups, such as polyhydroxylated aromatics and indoles, and more oxidized acceptor groups (e.g. quinones or other oxidized aromatics) as the molecular complexity of the DHS increased.
在这项研究中，我们表明，一系列来源不同的溶解有机质（DHS）的几个 UV-Vis 吸光度、稳态和时间分辨荧光参数与每摩尔有机碳的 280nm 摩尔吸光率（ε（280））相关，而 ε（280）又与 DHS 的分子复杂性（如分子大小、芳香度和氧化程度）成正比。吸光度和荧光光谱响应都对与 DHS 成熟度相关的分子复杂性敏感。根据 DHS 的不同，在吸收光谱的 UVA（340nm）和 VIS（460nm）区域的激发下观察到不同的发射响应。结果根据 DHS 分子复杂性的增加，从电子供体基团（如多羟基芳香族化合物和吲哚）与更氧化的受体基团（如醌或其他氧化芳香族化合物）之间的分子内电子相互作用程度进行了解释。
