Elemental and Molecular Geochemistry (GEM)

The specialized technical “Elemental and Molecular Geochemistry” service (GEM Service) is a high-performance analytical resources center dedicated to elemental and molecular analyses of environmental samples (surface water, groundwater, plants, micro-organisms, biogenic samples, etc.). This service performs over 7000 analyses each year.

HPLC/A4F/ICP-MS coupling
  1. GEM’s profile and missions
  2. Members

GEM’s profile and missions

The specialized analytical “Elemental and Molecular Geochemistry” service (GEM) of Geosciences Rennes was created in January 2009 following an internal reorganization of the research laboratory unit's shared services. It is a follow-up to the “Analytical Geochemistry” Workshop (GCA - GéoChimie Analytique) which included, in addition to GEM’s instruments and missions, the present activities of the Geochemical Experimental Technical Laboratory. The topics for this laboratory stemmed from the desire to create a high-performance analytical resources center dedicated to elemental and molecular analyses of environmental samples (water, plants, micro-organisms, biogenic samples, etc.). This structure is open to researchers from Geosciences Rennes and the units at the Rennes Earth Science and Astronomy Observatory (OSUR), to promote establishments collaborating with these units and potentially to a lesser degree, and subject to availability, to private organizations. This service is made up of different analytical instruments (quadrupole ICP-MS possibly coupled to a HP-LC or an A4F, Ion Chromatography, Furnace/Flame Atomic Absorption, Carbon Analyzer, etc.) as part of a joint quality approach. Quality approach refers to a high-level standard required for publication in international journals with a high impact factor (standardization, international standards analyses, inter-calibrations, etc.). The engineers who work daily in this structure running analyses, developing methods, undertaking sampling campaigns or developing biogeochemical experiments on Water/Soil/Biosphere interactions and their monitoring over time, also take part in the scientific projects and events undertaken by the Geochemistry of Water and Interfaces (Géochimie des Eaux et des Interfaces (GEI)) team at Geosciences Rennes.
This service unit, which is also part of the Common Analytical Center of OSU Rennes, has three main missions that are described in detail below:

  • Logistical support for research projects

The primary mission of this service is to provide the technical and analytical support needed by the members of Geosciences Rennes to carry out research projects. This includes the capacity to mobilize technical assistance for field trips including sampling and analytical methodological developments for the end purpose of elemental and/or molecular chemical analyses. Priority is placed on analyses for the research projects of the members of Geosciences Rennes, and a lower priority is placed on analyses falling outside these research programs. In this case, the requesting persons must actively take part in the analyses as the technical staff are already heavily involved in the research programs already being undertaken by Geosciences Rennes. Analyses considered as a third-level priority (analyses for private organizations, outside research settings) may be considered at higher rates, subject to the availability of the staff and equipment.

  • Support for teaching and training via sensu lato analysis

Although the human resources and operational equipment in the joint analytical center are dedicated to the research programs, whenever possible, they are also used in classes or training courses for students at the University of Rennes 1 or outside the university. The staff of this service can be involved in these training schemes when possible. In addition, through the technical supervision and training of PhD students in the area of analytic skills and particularly its critical processing, the training policy of this analytical service is fully complementary to the training provided by PhD supervisors.

  • Analytical support for observation tasks carried out by Geosciences Rennes and OSU

Logistical support for observation tasks is also a very important mission of this analytical service, since observation tasks are the key point of OSUR's constitution and are already at the forefront of the projects led by researchers from Geosciences Rennes within the OZCAR Research Infrastructure made up of the AgrHys Environment Research Observatory (ERO) and the H+ ERO.
These projects involve both the fluid circulations in fractured media, acquisition mechanisms for the chemical composition of water and its spatio-temporal evolution during climate or anthropogenic forcings. These observation tasks require various types of contributions from the joint service along with the design of field devices, a strong investment in the field (installation of sites, sampling, monitoring, etc.), the analysis of a large number of chemical determinants at numerous sampling sites and this may involve taking frequent samples and over a long period of time as well as their validation and entry into the corresponding  databases