The platform STABLE ISOTOPES is an instrumental platform of Aix Marseille University dedicated to the analysis of the stable isotopes in solid, liquid and gaseous samples by isotope mass spectrometry. These analyses are at present possible for 5 elements which are particularly important for the living matter, for water and in order to characterize organic pollutants: hydrogen, carbon, nitrogen, oxygen and sulfur. The platform can follow the isotopic ratios 2H/1H, 13C/12C, 15N/14N, 18O/16O and 34S/32S. Solid or liquid samples of 200-500 micrograms can be analyzed by elementary analysis. For gases and volatile and semi-volatile pollutants, a separation by gas chromatography allows to reaching the isotopic reports in specific compounds.
Patrick Höhener Tel (+33) 4 13 55 10 34
Didier Gori Tel (+33) 4 13 55 07 95
DESCRIPTION OF EQUIPEMENTS
Elementary analysis: the platform comprises an elementary analyzer (Flash2000 HT +) coupled to an isotope mass spectrometer Delta V Advantage (THERMO FISHER) to analyze the isotopes of 2H, 13C, 15N, 18O and 34S in solid and liquid samples. The CONFLOW IV (Thermo Fisher) system is used to introduce reference gases to assure the stability and the linearity of the system. A microbalance METTLER serves for an exact weighing of samples in ranges between 200 and 500 micrograms.
Compound-specific isotope analysis: the compound-specific analysis is made possible by coupling a gaseous chromatography (Trace 1310 - Thermo Fisher) via the interfaces ISOLINK II and CONFLOW IV to the isotope mass spectrometer Delta V Advantage (THERMO FISHER). This coupling allows to measuring the isotopes 2H, 13C, and 15N in specific compounds. The gas chromatography has a flame ionization detector for the quantification of concentrations.
DESCRIPTION OF CONCRETE APPLICATIONS
- Forensic studies on the origin of the pollutions in soils and ground water. Application in chlorinated solvents, petroleum products and cyanides.
- Diagnosis of the reactivity of organic pollutants on sites contaminated in the case of the regulated natural attenuation. Application to the crude oil in the aquifer of Crau.
- Kinetic studies of degradation of hydrocarbons and halogenated organic compounds volatile (COHV) and followed by cleanup of the industrial sites.
- Modelling of stable isotopes in pollutants in ground water to have a better understanding of the processes which act on a pollutant on a contaminated site. Software for the isotopes 13C, 2H and 37Cl in industrial pollutions were published and are freely available on the journal websites.
- Water isotopes: (2H, 18O) for the study of the hydrological cycle.
- Study of the green waste during composting and studies of traceability of compost and wastes.
- Application of isotopes in studies on trophic networks. By analyzing the isotope ratios of a consumer and its potential food, it is possible to reconstitute the likely diet of the consumer.