STABLE ISOTOPESOXYGEN 18Equipment
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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:
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:
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URL http://geology.cr.usgs.gov/capabilities/gronemtrac/geochem/stablei/oxygen/equip.html
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