Department of Chemistry and CESAM, University of Aveiro, Campus de Santiago 3810-193 Aveiro, Portugal; Department of Chemistry and CICECO, University of Aveiro, Campus de Santiago 3810-193 Aveiro, Portugal.
CIIMAR - Interdisciplinary Centre of Marine and Environmental Research, Terminal Cruzeiros do Porto de Leixões, 4450-208, Matosinhos, Portugal.
Chemosphere. 2019 Apr;220:565-573. doi: 10.1016/j.chemosphere.2018.12.149. Epub 2018 Dec 21.
Reliable determination of mercury (Hg) in natural waters is a major analytical challenge due to its low concentration and to the risk of Hg losses or contamination during sampling, storage and pre-treatment of samples. The present work proposes a simple, efficient, sensitive and easy-handling methodology for extraction, pre-concentration and quantification of total dissolved mercury in natural waters, using iron oxide nanoparticles (NPs) coated with silica shells functionalized with dithiocarbamate groups (FeO@SiOSiDTC). Ten mg L of these NPs were sufficient to remove 83-97% of 500 to 10 ng L of Hg in ultra-pure water and artificial seawater, used as model Hg solutions, within 24 h. Mercury sorbed to the NPs was then measured directly by thermal decomposition atomic absorption spectrometry with gold amalgamation. The detection limit of approximately 1.8 ng L is lower than the values reported in dispersive solid phase extraction for other magnetic sorbents. As a proof-of-concept, the proposed methodology was successfully tested in real samples of fresh and saline waters and more than 91% of Hg was recovered. With this methodology the extraction and pre-concentration steps may be carried out in situ decreasing the risk of Hg losses or contamination during sampling, storage and pre-treatment of water samples.
由于汞（Hg）浓度低，且在采样、储存和样品预处理过程中存在 Hg 损失或污染的风险，因此可靠地测定天然水中的汞（Hg）是一项主要的分析挑战。本工作提出了一种简单、高效、灵敏且易于操作的方法，用于萃取、预浓缩和测定天然水中的总溶解汞，所用的萃取剂为用二硫代氨基甲酸盐基团功能化的硅壳包裹的氧化铁纳米颗粒（FeO@SiOSiDTC）。10 mg/L 的这些 NPs 在 24 小时内足以从超纯水和人工海水中 500 到 10 ng/L 的 Hg 中去除 83-97%。然后通过金汞齐化的热解原子吸收光谱法直接测量吸附在 NPs 上的 Hg。约 1.8 ng/L 的检测限低于其他磁性吸附剂在分散固相萃取中报道的值。作为概念验证，该方法已成功应用于淡水和盐水的实际水样中，Hg 的回收率超过 91%。使用这种方法，可以在现场进行萃取和预浓缩步骤，从而降低采样、储存和预处理水样过程中 Hg 损失或污染的风险。
