About the Department

PSSRI has several laboratories dedicated to light element stable isotope mass spectrometry. Each laboratory focuses on different scientific objectives, employing a variety of analytical approaches. Much of the research includes a strong element of instrument and technique development, which includes a two way exchange with the spaceflight instrumentation programmes.

 

The main analytical labs are:

Oxygen 3-isotope:  The front line instrument is a laser fluorination system employing a CO2 laser and a Micromass PRISM III for high precision oxygen 3-isotope analyses of meteoritic materials. A MAT 253 with dual- and continuous flow-inlets is coupled to the laser fluorination system for small sample analyses and a water extraction system. A static mass spectrometer system is also under development, coupled to a 193nm excimer laser for Genesis solar wind oxygen analysis.

Organic geochemistry:  There is an extensive range of facilities for the analysis of organic compounds from extraterrestrial and terrestrial samples. The instruments are housed in a modern, purpose-built, laboratory with adjoining general chemistry and sample preparation facilities.

There is MAT 253 configured for D/H, C and N isotopic measurements with a GC-combustion sample introduction system providing isotopic measurements of individual compounds in a complex mixture. Supporting this instrument is a MAT Delta with a GasBench for automated carbonate analyses and a PDZ Europa Geo20-20 with ANCA elemental analyser for D/H, C and N bulk analyses.

High Sensitivity C, N and noble gases:  Perhaps the most important analytical tools in PSSRI are the hi-sensitivity static vacuum mass spectrometers that have been designed and built within the group. The static mass spectrometers used in PSSRI utilise the actual mass spectrometer as the sample reservoir in the same manner as a noble gas instrument. This provides a gain in sensitivity of up to 4 orders of magnitude with a loss in precision of about 1 order of magnitude compared to dual inlet instruments.  As  most  meteorite samples are generally very precious but contain large isotopic variations this is a more than acceptable compromise.

Coupled with the development of the analysers has been the successful development of the sample extraction systems to quantitatively deliver and purify such small samples without significant contribution of system blanks and that the reference gas can be metered out in appropriate sized aliquots without blank and unfractionated.