State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
Talanta. 2021 Dec 1;235:122738. doi: 10.1016/j.talanta.2021.122738. Epub 2021 Jul 30.
Heavy metal speciation and distribution is significantly influenced by dissolved organic matter (DOM) exhibited in ecosystems, particularly in urbanized rivers. Synchronous fluorescence spectroscopy (SFS) conjunct second derivative and two-dimensional correlation spectroscopy (2D-COS) was devoted to characterizing interactions of DOM-copper (II). Three typical water samples were collected from Baitapu River. Only protein-like fluorescence (PLF) and fulvic-like (FLF) were identified from the SFS. Stability constant (log K) values of PLF complexes with copper (II) varied from 4.277 to 5.833, and proportion of binding fluorescent materials (f) were 0.054-2.640. The log K values of FLF complexes with copper (II) varied from 3.996 to 4.243, while the f values were 0.001-0.036. Obviously, PLF had much stronger complexing capacity than FLF. There were four obvious peaks in the principal component analysis and second derivative fluorescence spectroscopy (SDFS), i.e., tyrosine-like (TYLF), tryptophan-like (TRLF), microbial humus-like (MHLF) and FLF. The log K values of TYLF and TRLF complexes were 4.899-5.907 and 4.598-5.831, respectively, which were similar to those from PLF. The log K values of MHLF complexes varied from 4.311 to 5.760, and the f values were 0.261-8.688. The log K values of FLF complexes were ranged from 4.598 to 5.831, which were higher than those deduced from the SFS. Interestingly, by the SDSF, PLF was divided into TYLF and TRLF, which increased the parameters values from DOM-copper (II) complexes. 2D-SFS-COS revealed that the TRLF was more susceptive response to copper (II) appended than TYLF, MHLF, and FLF. Moreover, TYLF and TRLF could priorly interact with copper (II). The SDSF conjunct 2D-COS could be effective approaches for insight into the complexing heterogeneity of DOM with copper (II). The study could present a support to preventing heavy metals and organic pollution in urbanized rivers.
重金属形态和分布受生态系统中溶解性有机质（DOM）的显著影响，尤其是在城市化河流中。同步荧光光谱（SFS）结合二阶导数和二维相关光谱（2D-COS）被用于表征 DOM-铜（II）的相互作用。从八家子河采集了三个典型的水样。SFS 只鉴定出蛋白质样荧光（PLF）和富里酸样荧光（FLF）。PLF 与铜（II）形成配合物的稳定常数（log K）值范围为 4.277 至 5.833，结合荧光物质的比例（f）为 0.054-2.640。FLF 与铜（II）形成配合物的 log K 值范围为 3.996 至 4.243，而 f 值为 0.001-0.036。显然，PLF 具有比 FLF 更强的络合能力。主成分分析和二阶导数荧光光谱（SDFS）中有四个明显的峰，即酪氨酸样（TYLF）、色氨酸样（TRLF）、微生物腐殖质样（MHLF）和 FLF。TYLF 和 TRLF 配合物的 log K 值分别为 4.899-5.907 和 4.598-5.831，与 PLF 相似。MHLF 配合物的 log K 值范围为 4.311 至 5.760，f 值为 0.261-8.688。FLF 配合物的 log K 值范围为 4.598 至 5.831，高于从 SFS 推断出的 log K 值。有趣的是，通过 SDSF，PLF 被分为 TYLF 和 TRLF，这增加了 DOM-铜（II）配合物的参数值。2D-SFS-COS 表明，TRLF 对铜（II）的附加响应比 TYLF、MHLF 和 FLF 更敏感。此外，TYLF 和 TRLF 可以优先与铜（II）相互作用。SDSF 结合 2D-COS 可以为深入了解 DOM 与铜（II）的络合异质性提供有效的方法。该研究可为防治城市化河流中重金属和有机污染提供支持。
