Traceability of Hg measurements and sensors

(1) to improve and validate analytical methods for gaseous Hg speciation needed in atmospheric measurements (ESR10) and (2) to develop in-situ biosensors for the determination of the bioavailable fraction of Hg in the aquatic environment (ESR11) and (3) to test new and validated methodologies for analysing the atmosphere and water during field campaigns.

Task 4.1. To secure comparability of atmospheric measurements traceable calibration methodology (with stated uncertainties) for the most important oxidized Hg species will be applied for low level atmospheric measurements under contrasting conditions during lab and field campaigns. This will be done via a traceable Hg(0) standard developed by VSL where the ESR 10 will be seconded twice.  Conventional calibration will be tested against newly developed plasma source of Hg(II) followed by mass spectrometry detector. Improved conventional measurement methods based on selective sorbent trapping, denuders and impingers developed and tested by MercOx project coordinated by PC (www.mercox.si) will be applied in WP1 and 2. Also, high accuracy bulk and species-specific [e.g. Hg(0) and Hg(II)] isotope ratio measurements by MC-CP-MDS will be evaluated for origin discrimination during secondment at the JSI. The methods validated for atmospheric measurements will be tested using new and conventional methods for Hg speciation measurement in the atmosphere during field measurements campaigns organized by WP1 and 2.

Task 4.2. ESR11 will develop a highly specific, robust and sensitive MMHg biosensor. In phase I, the ESR11 will develop approaches of using information stored in DNA. By the D/RNA manipulation ESR11 will prepare biomolecules, either DNA, RNA or proteins, that specifically bind to MMHg. This work will be implemented together with the JSI that will host ESR11 during their secondments. Two approaches will be used (i) based on directed evolution applying synthetic biology circuits to increasing specificity of binding of proteins and (ii) by using a selection process (SELEX) of RNA and DNA molecules resulting in aptamers with high MMHg affinity constants and specificity. The final structure of the biosensor will depend on the nature of the biological components, on the nature of the inverter and on the corresponding detection methods. In phase II, ESR11 will validate the developed biosensor by making parallel measurements using conventional analytical methods on different types of environmental samples obtained from AMU, IFREMER, and SU.