Characteristics

Stable isotopes are non-radioactive atoms of a particular chemical element which have the same number of protons but different number of neutrons. The relative abundance of the heavy compared with the light isotope (e.g. 13C/12C) is given the name isotopic signature or fingerprint and is represented by a delta symbol (δ) by means of the ratio of this proportion in the sample, with respect to international standards, giving the results in units per thousand (‰).

The Doñana Biological Station (EBD) Stable Isotope Laboratory (LIE) is equipped with a Mass Spectrometry system, supplied by Thermo Fisher Scientific, to measure the isotope ratios 13C/12C, 15N/14N, 18O/16O, 34S/32S and 2H/1H in organic and inorganic, solid or liquid samples.

This Laboratory was founded thanks to funding from the project: “Adapting to Global Change in the Mediterranean hotspot: from genes to ecosystems (EcoGenes)”.

Here we give you a virtual tour of the EBD, funded through EcoGenes, in which you can see all the laboratories including the LIE.

Equipment

DELTA V Advantage IRMS in continuous flow mode, with a system of 5 collectors for measuring isotopic ratios in N2, CO, NO, O2, CO2, N2O, SO2 and H2.

Flash HT Plus Elemental Analyzer connected to an IRMS via the Conflo IV. With two furnaces installed for two modes of operation: “Dynamic Flash Combustion” for isotopic analysis of C, N and S; and “High Temperature Conversion” for isotopic analysis of O and H.

Picarro L2130-i CRDS (Cavity Ring Down Spectroscopy) Laser Spectrometer for continuously measuring the stable isotopes of Hydrogen and Oxygen in water and water vapour.

GasBench II Universal on-line gas preparation system. The GasBench II system provides high-precision on-line isotope and molecular ratio determination of headspace gas, including water equilibration, carbonates, and atmospheric gases (e.g. CO2, O2/N2).  A series of nafion traps remove water and a GC column separates gases in time for analysis of isotopic composition largely free of interference. This system is able to attain nearly the precision and accuracy of a dual inlet system on a continuous-flow IRMS system.

Contiunous flow mass spectrometry system (GC-MS-IRMS) for the automated measurement of isotopic ratios of carbon, nitrogen and hydrogen in specific compounds.