Stable Isotope Laboratory
Eng. František Bůzek, CSc.
Head of the Laboratory
tel. (00420) 251 085 345 / 319
The Laboratory of Stable Isotopes offers routinely available analyses including:
- the determination of 13C and 18O in carbonates
- 2H and 18O in waters
- 13C in solid, liquid and gaseous organic materials
- 15N in organic materials and solutions
- 18O in sulfates
- 34S in sulfides and sulfates.
The laboratory has participated in several international calibration exercises (sulfur and carbon standards) and has collaborated in geological, paleoenvironmental, biogeochemical & hydrogeological projects.
Geochemistry of stable isotopes studies minute changes in the natural abundance ratios of isotopes of light elements (2H/1H, 13C/12C, 15N/14N, 18O/16O, and 34S/32S). These changes are caused by small differences in physical and chemical properties between the heavy and the light isotope of each element. Precise measurement of isotope ratios makes it possible to specify sources, dispersion pathways and sinks of the species under study. Some processes are associated with characteristic isotope fractionations which can be used to diagnose these processes in complex systems. For the measurement itself, it is necessary to convert all compounds to simple gases (H2, CO2, N2 and SO2). Proper sample preparation is crucial to mass spectrometric analysis, and therefore much time and energy is dedicated to refinement of the vacuum line procedures used for gas preparation.
Methods & instrumentation
The Laboratory is equipped with two mass spectrometers, Finnigan MAT 251 and Geo 20-20. Both mass specs can measure isotope ratios in the conventional dual mode (i.e., compare isotope compositions of a sample and a standard; ˛dual mode IRMS˛), and also in the continuous flow mode (an on-line set-up comprising elemental analyser Fisons 1108 and the mass spec). The continuous flow mode enables fast combustion of the sample, chromatographic separation of the gas, and injection of the gas into the mass spec by means of a ConFlo unit (˛flash combustion-GC-IRMS˛).
For the conversion of the sample to a gas suitable for conventional dual mode mass spectrometry, the Laboratory operates a number of preparatory lines. Routinely available methodologies include: determinations of 13C and 18O in carbonates, 2H and 18O in waters, 13C in solid, liquid and gaseous organic materials (with possible chromatographic separation of species in gaseous mixtures). 15N in organic materials and solutions (NH4+, NO3-), 18O in sulphates, and 34S in sulphides and sulphates. Analysis of 18O in quartz, silicates and whole-rock samples is made possible through collaboration with the Faculty of Science, Charles University, Prague. The Stable Isotope Laboratory of the Czech Geological Survey has participated in several international calibration exercises (suphur standards IAEA-S-1, IAEA-S-2 and IAEA-S-3, and gas standards IMEP-8A and IMEP-8B).
The Laboratory is involved in collaborative projects with a number of partner institutions and coordinates its own research projects:
- IAEA 8397/R1 "Nitrate pollution of karstic groundwater system”
- CarboEurope EU Project FORCAST – Forest Carbon-Nitrogen Trajectories"
- GA ČR 205/97/0059 "Formation, Migration and Accumulation of Coal Methane and its Contribution to the Budget of Atmospheric Methane"
- Dry Climatic Phases of Mid-Holocene: Correlation of Isotope and Biostratigraphic Methods
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Oxygen Isotopes in Sulphate as an Environmental Tracer
- Peatlands and Global Change: The Stable Isotope Approach
- GA ČR 205/95/1392 “Dry climatic phases of Middle Holocene - correlation of isotopic and biostratigraphic methods”
- IAEA 7119/R1 “Stable isotope climatic record in Quaternary sediments of the Bohemian Massif”
The Laboratory participates in supervising Master theses and Dissertations of university students.
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