MERcury Electrochemical SENSor for in situ trace determination (MERESENS)

• Applicant: Professor Dr. Thomas Pichler, since 12/2015
• Subject Area: Analytical Chemistry ; Hydrogeology, Hydrology, Limnology, Urban Water Management, Water Chemistry, Integrated Water Resources Management
• Term: from 2015 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 284165628

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.

• DFG Programme: Research Grants
• International Connection: France
• Partner Organisation: Agence Nationale de la Recherche / The French National Research Agency
• Cooperation Partner: Dr. David Evrard
• Ehemaliger Antragsteller: Dr. Lars-Eric Heimbürger, until 12/2015