Stock Vivian, Mutschler Anna, Lindén Mika, Leopold Kerstin
Department of Analytical and Bioanalytical Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
Department of Inorganic Chemistry II, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
Nanomaterials (Basel). 2021 Feb 18;11(2):512. doi: 10.3390/nano11020512.
Mercury detection in humic matter-containing natural waters is often associated with environmental harmful substances for sample preparation. Herein we report an approach based on photoactive titanium dioxide films with embedded gold nanoparticles (AuNP@TiO dipstick) for chemical-free sample preparation and mercury preconcentration. For this purpose, AuNPs are immobilized onto a silicon wafer and further covered with a thin photoactive titanium dioxide layer. The AuNPs allow the preconcentration of Hg traces via amalgamation, while TiO acts as a protective layer and, at the same time, as a photocatalyst for UV-C radiation-based sample pretreatment. Humic matter, often present in natural waters, forms stabile complexes with Hg and so hinders its preconcentration prior to detection, causing a minor recovery. This problem is solved here by irradiation during Hg preconcentration onto the photoactive dipstick, resulting in a limit of detection as low as 0.137 ng L using atomic fluorescence spectrometry (AFS). A 5 min preconcentration step is sufficient to obtain successful recovery of Hg traces from waters with up to 10 mg L DOC. The feasibility of the approach was demonstrated by the determination of Hg traces in Danube river water. The results show no significant differences in comparison with standard cold vapor-atomic fluorescence spectrometry (CV-AFS) measurements of the same sample. Hence, this new AuNP@TiO dipstick provides a single-step sample preparation and preconcentration approach that combines sustainability with high analytical sensitivity and accuracy.
在含有腐殖质的天然水体中检测汞时，样品前处理往往会涉及环境有害物质。在此，我们报道一种基于嵌入金纳米颗粒的光活性二氧化钛薄膜（AuNP@TiO试纸）的方法，用于无化学试剂的样品前处理和汞预富集。为此，将金纳米颗粒固定在硅片上，并进一步覆盖一层薄的光活性二氧化钛层。金纳米颗粒通过汞齐化作用实现汞痕量的预富集，而二氧化钛作为保护层，同时作为基于紫外-C辐射的样品预处理的光催化剂。天然水体中常存在的腐殖质会与汞形成稳定络合物，从而在检测前阻碍其预富集，导致回收率较低。在此，通过在汞预富集到光活性试纸上的过程中进行辐照解决了这个问题，使用原子荧光光谱法（AFS）时检测限低至0.137 ng/L。5分钟的预富集步骤足以成功回收来自溶解性有机碳含量高达10 mg/L的水体中的汞痕量。通过测定多瑙河水中的汞痕量证明了该方法的可行性。结果表明，与同一样品的标准冷蒸气原子荧光光谱法（CV-AFS）测量结果相比，没有显著差异。因此，这种新型AuNP@TiO试纸提供了一种将可持续性与高分析灵敏度和准确性相结合的单步样品前处理和预富集方法。
