Developing new Nanogold-based Test Strip for Environmental and Bio-Monitoring of Mercury (HG) Traces - NANOTEHG -

尽管工业国家在过去25年里为减少汞排放做出了很大努力，但全球人为排放仍略有增加。它在小规模金矿开采中的过度使用，以及燃煤发电厂排放的增加，都是汞排放的主要原因。因此，这种剧毒的重金属仍然是最关键的环境污染物之一。如今，食用鱼类被认为是人类汞暴露的主要来源。然而，发展中国家的黄金矿工和工业工人仍然存在较高的职业暴露。因此，为了防止汞对人体的负面影响，对汞的环境和生物监测是强制性的。虽然有各种高灵敏度和选择性的分析方法可用于汞的测定，但这些方法都有一些缺点，如消耗剧毒试剂、耗时的样品制备和庞大的仪器。因此，需要进一步发展，以便为快速监测真实世界样品中的汞痕量提供简化的程序。该项目的目的是开发一种可靠而有效的分析方法来测定水样中的痕量汞，如天然水、人类尿液、酸性/碱性提取物等。为此，将准备一条试纸，将其浸入液体样品中几分钟，以积累汞。探测器将由硅片上的介孔多孔硅膜组成，硅片的孔洞中含有金纳米颗粒。在所有溶解的汞物种被催化分解成Hg0和随后的汞齐后，汞选择性地和高效地积累在这个纳米金修饰的薄膜上。除了采用常见的被动抽样方法外，没有计划在实地/抽样中进行部署。此外，在浸入样品之前，用有机溶剂填充试纸的毛孔将提供特定物种的汞积累。从探头上解吸汞将以热的方式进行，而不需要任何浸出剂。用原子荧光光谱法测定汞蒸气。催化活性金纳米颗粒的再生也是通过这个加热步骤实现的。因此，完整的分析程序将不使用试剂，使用可重复使用的试纸，提供关键的优势，如简单和低成本的现场处理，同时提供高灵敏度和选择性。因此，新的方法将是一个非常有价值的环境和生物监测工具。

Even though industrial countries have made great efforts to reduce Hg emission over the last 25 years, global anthropogenic emission still increases slightly. Its excessive use in small-scale gold mining and increasing emissions from coal-fired power plants contribute mainly to Hg discharges. Therefore, this highly toxic heavy metal is still one of the most critical environmental pollutants. Consumption of fish is nowadays considered as the main source for general human Hg exposure. However, high occupational exposure still occurs for gold miners and workers in industry in developing countries. Hence, environmental as well as bio-monitoring of Hg traces is mandatory in order to prevent negative effects on humans.Although there are various highly sensitive and selective analytical methods available for Hg determination, these have several disadvantages, like consumption of highly toxic reagents, time-consuming sample preparation, and bulky instrumentation. Hence, further development in order to provide simplified procedures for rapid monitoring of Hg traces in real-world samples is required. The aim of the project is to develop a robust and valid analytical method for determination Hg traces in aqueous samples, like natural waters, human urine, acidic/basic extracts, etc. For this purpose, a test strip will be prepared that is dipped for a few minutes into a liquid sample in order to accumulate Hg. The probe will consist of a meso-porous silicon film on a silicon wafer containing gold nanoparticles in its pores. Selective and highly efficient accumulation of Hg onto this nanogold-modified thin film takes place after catalytic decomposition of all dissolved Hg species into Hg0 and subsequent amalgamation. Other than with common passive sampling approaches no deployment in the field/sample is planned. Furthermore, filling the pores of the test strip with organic solvents prior to dipping into the sample shall provide species-specific accumulation of Hg. Desorption of Hg from the probe will be performed thermally omitting the necessity of any leaching reagents. Hg0 vapour is detected by atomic fluorescence spectrometry. Regeneration of the catalytic active gold nanoparticles is achieved by this heating step, too. Hence, the complete analytical procedure will work reagent-free with a re-useable test strip, providing crucial advantages, such as simple and low-cost on-site handling and at the same time providing high sensitivity and selectivity. Therefore the new method will be a very valuable tool for environmental and bio-monitoring.