MERcury Electrochemical SENSor for in situ trace determination (MERESENS)

重金属，特别是汞(Hg)，对环境和健康的影响越来越大。汞以无机和有机金属形式存在，例如有毒的和生物积累的甲基汞(MeHg)形式。甲基汞的生产取决于无机汞(II)的浓度和(生物)有效性。到目前为止，汞(II)浓度的监测主要是通过光谱技术，如耦合冷原子荧光光谱分析(CVAFS)。这些技术需要昂贵的材料，与复杂和耗时的程序相关，因此限制了任何现场或在线和手术分析。MERESENS项目旨在开发一种可靠的工具，在与环境有关的水平上现场测定汞(II)。我们建议根据欧洲水框架指令(指令2000/60/EC)和海洋战略框架指令(指令2008/56/EC)以及欧洲成员国以优化成本资助监测网络和项目的要求，开发和测试一种用于生态系统监测的新型电化学汞传感器。我们将开发一种基于金纳米颗粒(AuNPs)和重氮化合物功能的玻璃碳(GC)电极的电化学传感器。这些传感器将在天然水中进行汞(II)痕量测量，并经过优化以表现出良好的灵敏度和选择性以及随时间推移的重现性和稳定性。使用AuNPs对电极表面进行功能化处理将提高对低水平Hg(II)的灵敏度，而重氮化合物将通过与GC表面的共价锚定确保AuNPs在电极上的稳定性。通过不同的参数，如有机层厚度和结构，以及AuNPs的尺寸和密度，将产生大量的功能化界面。通过电化学(循环伏安法、电子阻抗谱和扫描电化学显微镜)和物理化学技术(场发射扫描电子显微镜、原子力显微镜、掠入射小角度X射线散射)对所有电极进行了表征。它们的分析性能(选择性、灵敏度、检测限、重复性和稳定性)将通过检查它们对合成和天然水中不同浓度的汞(II)的电化学响应来评估。将使用大量的天然水样来测试该传感器，以验证其在许多基质条件下提供可靠响应的能力。所获得的结果将通过参考技术CVAFS进行验证。应该实现并可获得具有很好稳定性的高灵敏度和选择性的电化学传感器，并将达到技术准备等级3。预计在了解AuNPs与有机重氮薄膜和GC表面的相互作用方面将取得重大进展。

Heavy metals and particularly mercury (Hg), represent a growing environmental and health concern. Hg is present as inorganic and organometallic species such as the toxic and bioaccumulating methylmercury (MeHg) form. MeHg production depends on the concentration and (bio-)availability of inorganic Hg(II). To date, Hg(II) concentration is mainly monitored by spectrometric techniques, such as coupled cold-vapor atomic fluorescence spectrometry (CVAFS). These techniques require expensive materials associated to complex and time-consuming procedures, thus limiting any in situ or on line and operando analysis. The MERESENS project aims at developing a reliable tool for in situ determination of Hg(II) at environmentally relevant levels. We propose to develop and test a novel electrochemical Hg sensor for ecosystem monitoring in line with both European Water Framework Directive (Directive 2000/60/EC) and Marine Strategy Framework Directive (Directive 2008/56/EC) and requirements of European member states to fund monitoring networks and programs at optimized costs.We will develop an electrochemical sensor based on glassy carbon (GC) electrodes functionalized by gold nanoparticles (AuNPs) and diazonium compounds. These sensors will be tested for Hg(II) trace measurements in natural waters and optimized to exhibit good sensitivity and selectivity as well as reproducibility and stability over time.The use of AuNPs to functionalize the electrode surface will enhance the sensitivity for low Hg(II) levels, whereas diazoniums will ensure the AuNPs stabilization on the electrode by affording a covalent anchoring with GC surface. A large set of functionalized interfaces will be produced by varying parameters such as organic layer thickness and structuration, and AuNPs size and density. All the resulting electrodes will be fully characterized by electrochemistry (cyclic voltammetry, electron impedance spectroscopy and scanning electrochemical microscopy) and physicochemical techniques (field emission scanning electron microscopy, atomic force microscopy, grazing incidence small angle X-ray scattering). Their analytical performances (selectivity, sensitivity, limit of detection, repeatability, and stability) will be evaluated by checking their electrochemical response to varying Hg(II) concentrations for synthetic and natural waters. A large panel of natural water samples will be used for testing the sensor in order to verify its capability to afford a reliable response in many matrix conditions. The obtained results will be verified by using reference technique, CVAFS.A highly-sensitive and selective electrochemical sensor which exhibits very good stability for possible long-term deployment should be achieved and available, and the Technology Readiness Level 3 will be reached. Major advances are expected in the understanding of the interactions of the AuNPs with the organic diazonium films and the GC surface.