Light element (C,N,O & H) stable isotopes

The isotope analysis techniques provided by the AAC are based around inductively coupled plasma (ICP) instruments. The fact that samples are introduced to the plasma in a normal atmospheric environment and the lens design of the instrumentation precludes the analysis of the light element isotopes (carbon, nitrogen, oxygen and hydrogen). A dedicated facility for this type of analysis is managed and operated at JCU by the School of Earth and Environmental Sciences (Cairns Campus).

Stable-isotope Facility (JCU-Cairns campus)

Stable-isotopes are powerful tracers of chemical and biological transformations, both in natural environments and in laboratory experiments. Stable isotope measurements are used extensively in geoscientific, ecological, chemical and archaeological research for studies of the biosphere, atmosphere and oceans, palaeoenvironmental reconstruction, food web, dietary and metabolic studies, studies of molecular and biomolecular reactions, environmental chemistry and monitoring.

The stable-isotope facility in the School of Earth and Environmental Sciences at JCU-Cairns has the capacity to determine the stable-isotope composition of carbon, nitrogen, oxygen, sulphur and hydrogen in microgram quantities of natural and synthetic materials, including solid or liquid samples containing organic matter, inorganic carbonates, water and atmospheric carbon dioxide. The laboratory is currently primarily used for studies of the biogeochemical cycling of carbon and nitrogen, biomass burning, palaeoenvironmental reconstruction, archaeology, ecology and palaeoceanography.

The laboratory is based around a Finnegan Delta-V gas source mass spectrometer, operated in continuous flow mode, coupled to (i) a Costech elemental analyser with zero blank auto-sampler for small sample measurements of organic matter in soils, sediments and biological material and (ii) a gasbench II preparation system for the automated analysis of carbonates, waters and gases. The mass spectrometer is supported by a full range of laboratory facilities for sample preparation and characterization including capacity for Fourier Transform Infra-Red Spectroscopy (FTIR). The facility also houses a hydrogen pyrolysis (hypy) rig, the fourth such instrument installed around the world. Hypy provides unique capacity for the quantification and isolation for isotope analysis of pyrogenic carbon (charcoal, biochar) in soils, sediments and aerosols.

For more information please contact: Professor Michael Bird