USGS-GD-Scientific Capabilities - STABLE ISOTOPES OXYGEN 18 Equipment





Nuclide 6-60, purchased in 1968, but extensively upgraded through the years is a semi-automated gas source isotope-ratio mass spectrometer (IRMS) originally used for routine sulfur, carbon, oxygen, and hydrogen isotope analyses. The principal use today is for larger problematic or 'dirty' samples. Located in Denver.

MAT 251, purchased in 1981, is an automated gas source isotope-ratio mass spectrometer (IRMS) used for analyzing carbon, oxygen, and hydrogen isotopes. This mass spectrometer is now used exclusively for carbonate carbon and oxygen isotope analyses that are prepared automatically on an attached Kiel Device. This Kiel device prepares CO2 from ultra small (5.0 micrograms) carbonate samples (e.g. individual foraminifers, coral laminae) in individual vials at the rate of 40 samples plus standards every 24 hours. The system is supported by an automated sampling device capable of sampling along growth zones of carbonates as thin as 10 microns. Located in Denver.

MAT 252, purchased in 1992, is an automated multi-purpose gas source isotope-ratio mass spectrometer used for analyzing carbon, hydrogen, sulfur, oxygen and nitrogen isotopes. The instrument is equipped with a microvolume for samples as small as 100 nanomoles and a cracker device for automated processing of gasses in 6mm closed tubes. Attached to the MAT 252 are two peripherals:

  1. A trapping box for the automated preparation of CO2 from carbonates, combusted organic samples, or water CO2 equilibrations.
  2. Gas chromatograph/open split interface that allows for isotopic analyses of ultra small (<10 nanomoles) samples of CO2, N2, and SO2 using state-of-the-art gas chromatograph isotope-ratio monitoring mass spectrometry (GC-IRMS) techniques. Located in Denver.

VG Optima, purchased in 1996, is a fully automated gas source IRMS with 5 collectors suitable for carbon, oxygen, nitrogen, hydrogen, and sulfur isotope analyses. Installed in February 1997, this instrument is equipped with 10 cracker tube inlet ports, a multiprep unit for automated CO2-water equilibration oxygen isotope measurements and carbonate acid digestion CO2 isotope analyses of 60 samples each loading, a multi-element analyzer for total combustion and analysis of carbon and nitrogen from the same sample sequentially, and/or sulfur isotope analyses all automated with a 50 sample carousel (approximately 5 minutes/analysis - 100 samples/day). The inlet manifold is equipped with a small automated sample cold finger to process samples with CO2 yields of several hundred nanomoles. Located in Denver.

Additional Special Equipment:

  • Microsampler (computerized drill capable of 10 micron spatial resolution)
  • CO2 laser/microscope for microbeam sampling and isotopic analysis (60 micron minimum beam diameter) - mid infrared.
  • Nd:YAG laser/microscope for microbeam sampling and isotopic analysis (15-20 micron minimum beam diameter) - near infrared.
  • Cold lab maintained at -30 °C for ice and biologic materials.
  • Kiel Carbonate device for automated carbon and oxygen isotopes by acid digestion.
  • Multiprep - automated carbonate (functionally replicates Kiel device) or water oxygen equilibration or water hydrogen equilibration.
  • GC Capillary OpenSplit Interface - continuous flow CO2 and SO2 isotopic analysis from gas chromatograph through capillaries.
  • Fluorination lines (BrF5 and F2) - unique to only several labs in world (no commercial facilities available).
  • Hydrous mineral/fluid inclusion/water hydrogen - unique to this lab.
  • Carbonate line

 | Capabilities |
| Geochronology, Geochemistry, and Tracer Studies  |
| Geochemistry, and Tracer Studies  |