GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstraße 1-3, 24148 Kiel, Germany.
Department of Chemistry, University of Lleida─AGROTECNIO-CERCA Center, Rovira Roure 191, 25198 Lleida, Spain.
Environ Sci Technol. 2021 Dec 7;55(23):16215-16223. doi: 10.1021/acs.est.1c04773. Epub 2021 Nov 12.
The physicochemical characteristics of dissolved organic matter (DOM) strongly influence its interactions with inorganic species such as protons and trace elements in natural waters. We collected water samples at Boknis Eck, a time series station in the Baltic Sea with a low exposure to freshwater inputs, to investigate how seasonal fluctuations impact the proton binding properties of the isolated DOM. We used potentiometric titrations to assess the binding properties of solid-phase extracted DOM (SPE-DOM) over a seasonal cycle. We report and critically analyze the first NICA parameters estimates of carboxylic-like and phenolic-like sites for brackish water SPE-DOM. The total amount of functional groups () showed no seasonal fluctuations and an average value of 136 ± 5.2 mmol·mol C. The average proton affinity (log) and binding site heterogeneity () showed a relatively minor variability for samples obtained between April and September, when the water remained stratified. These results contribute to a better understanding of the ion binding characteristics of DOM in natural brackish waters.
溶解有机物 (DOM) 的物理化学特性强烈影响其与天然水中质子和痕量元素等无机物质的相互作用。我们在波罗的海的一个时间序列站 Boknis Eck 采集了水样，该站受到淡水输入的影响较小，以研究季节性波动如何影响分离出的 DOM 的质子结合特性。我们使用电位滴定法在一个季节性周期内评估固相提取 DOM (SPE-DOM) 的结合特性。我们报告并批判性地分析了针对咸水 SPE-DOM 的羧酸样和酚样位点的第一个 NICA 参数估计值。功能基团的总量 () 没有季节性波动，平均值为 136 ± 5.2 mmol·mol C。当水保持分层时，在 4 月至 9 月之间获得的样品中，质子亲和力 (log) 和结合位点异质性 () 的平均值显示出相对较小的可变性。这些结果有助于更好地了解天然咸水中 DOM 的离子结合特性。
