Photochemical oxidation of thiols and copper complexing ligands in estuarine waters
Photochemical oxidation of thiols and copper complexing ligands in estuarine waters
复制标题
河口水域硫醇和铜络合配体的光化学氧化
DOI：
10.1016/j.marchem.2006.01.006
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发表时间：
2006
期刊：
影响因子：
3
通讯作者：
C. V. D. Berg
中科院分区：
文献类型：
--
作者：
L. M. Laglera;C. V. D. Berg
本文研究了有机铜络合配体在海洋沃茨中的可能光解作用，方法是在恒温箱中用天然太阳光和模拟的300- 350 nm波长的太阳光紫外组分照射河口沃茨。铜络合配体和硫醇化合物用阴极溶出伏安法测定。田间试验表明，光化学氧化的铜络合配体和硫醇化合物发生，但在可变的速率，由于在阳光强度和盐度的变化。通过暴露于阳光一天，配体浓度降低2%至60%，硫醇浓度降低30- 50%。培养箱实验证实，通过模拟日光，样品中存在的硫醇化合物以3 h的半衰期被分解，天然铜络合配体以20- 45 h的半衰期被分解。用铜饱和后，硫醇的半衰期增加了近十年。可能的是，几乎被铜饱和的L1型配体也比较弱的L2型配体分解得更慢。实验证实，太阳辐射分解了表面沃茨中的铜络合配体和硫醇化合物的显著部分。然而，这是可能的，这种光化学分解是少得多的铜稳定的配体，它是减少了向下混合的表面沃茨和随后的阴影溶解有机物和颗粒物在潮汐河口条件。
The possible photolysis of organic copper complexing ligands in marine waters is investigated here by irradiation of estuarine waters with natural sunlight and with the simulated UV component of sunlight at wavelengths of 300–350nm, typical for intermediate latitudes, in an incubator. Copper complexing ligands and thiol compounds were determined by cathodic stripping voltammetry. Field experiments showed that photochemical oxidation of the copper complexing ligands and thiol compounds occurred but at variable rates due to variations in the sunlight intensity and salinity. Ligand concentrations were decreased by between 2% and 60%, and thiol concentrations by 30–50%, by a day exposure to sunlight. The incubator experiments confirmed that the thiol compounds occurring in the samples were broken down with a half-life of 3h and natural copper complexing ligands with a half-life of 20–45h, by the simulated daylight. After saturation with copper, the half-life of the thiols increased by nearly a decade. It is possible that L1-type ligands, which are nearly saturated with copper, are also broken down more slowly than the weaker L2-type ligands. The experiments confirm that solar radiation breaks down a significant fraction of copper complexing ligands and thiol compounds in surface waters. However, it is likely that this photochemical breakdown is much less for ligands stabilised by copper, and it is reduced by downward mixing of the surface waters and subsequent shading by dissolved organic matter and particulate matter in tidal estuarine conditions.