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Isotope Ratio Mass Spectrometer

The Stable Isotope Mass Spectrometry Facility is housed and staffed within the Soil and Water Science Department (SWSD). The instrumentation was purchased and is maintained as a collaborative research facility by the SWSD, and UF Departments of Geological Sciences and Botany. Samples from other UF Departments as well as other outside entities can be submitted to the facility and current pricing can be obtained by contacting Dr. Kathryn Curtis.

The centerpiece of the facility is a Thermo Finnigan MAT Delta Plus XL mass spectrometer configured to measure stable isotope ratios of certain gases (especially CO2, N2, and N2O). Three peripherals are presently dedicated to the mass spectrometer for the purpose of delivering gas samples to the mass spectrometer:

  1. Elemental Analyzer (EA-IRMS)- A Costech Instruments elemental combustion system (ECS4010) is connected to the mass spectrometer for the purpose of flash combustion of soil, plant, and tissue samples to produce N2 and CO2. UHP Helium is used as a carrier gas to transport the gases produced during combustion thru a water trap to remove any water present in the gas stream prior to entering a GC column within the system where the N2 and CO2 are separated within the carrier gas before delivery through a ConFlo III interface to the mass spectrometer.

  2. Gas Chromatograph (GC-C-IRMS)- A modified Hewlett Packard HP 6890 is utilized for carbon isotope analysis via Isotope-Ratio-Monitoring Gas Chromatography (GC-C-IRMS). The GC-C-IRMS technique involves on-line separation of compounds (e.g. amino acids, FAMES, sterols and other hydrocarbons) from mixtures by gas chromatography. The gas chromatography effluents are combusted to CO2 and sent to the mass spectrometer continuously in a helium carrier stream.

  3. Gas Bench- A Thermo Finnigan GasBench III is used to measure gas samples in individual septa top vials.  Utilizing a CTC GC-PAL autosampler a double needle system takes headspace gas from sample vials and performs multiple isotopic analysis.  The GasBench system is primarily used for measuring gaseous CO2 from atmosphere, soil respiration, and dissolved inorganic carbon in water.  It is also used to measure N2O converted from nitrate via the microbial denitrifier method.


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Wetland Biogeochemistry Laboratory   Webmanager
P.O. Box 110290, Gainesville, FL 32611, Phone: (352) 294-3151
University of Florida |  IFAS  | Soil and Water Science

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Stable Isotope Mass Spec Lab
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Kathryn Curtis. (CV)
Stable Isotope Mass Spec Lab
Soil and Water Science Department
2169 McCarty Hall
University of Florida
Gainesville, FL  32611-0292
Phone: (352) 294-3117