Stable Isotope Laboratory

The Stable Isotope Lab has two gas-source isotope ratio mass spectrometers.

Lab Team

Principal Investigator: Xiahong Feng

Phone: (603) 646-1642


Lab Equipment

Isotopic ratios of the elements carbon, nitrogen, oxygen, hydrogen, and sulfur can be routinely measured. Converting a natural sample into gaseous form requires either manual preparation offline or the use of a peripheral device. The lab has glass vacuum lines for manual sample preparation and five peripheral units which automate the preparation of samples and input directly into a mass spectrometer. Types of samples that have been analyzed include water, DIC, snow, soil, soil gas, wood, cellulose, compound specific organic extracts, hair, fish, insects, and carbonates. In addition to the isotope ratio instrumentation, the lab has a DOC/DIC analyzer, a particle size analyzer and hosts glass-blowing facilities.
Mass Spectrometers

  • Delta+ XL
  • Delta+ Advantage

Peripheral Devices

  • H-Device
    • The H-Device allows for the automatic measurement of hydrogen isotopes in a liquid such as water or an organic extract. The liquid is injected and vaporized at 800-1000°C. The vapors react with chromium to produce Cr2O3 and H2 gas.
  • Gas Bench
    • The Gas Bench allows for the automatic measurement of oxygen isotopes in water using CO2 equilibration method, and in carbonates by their reaction with phosphoric acid. In both cases, CO2 is sent to an IRMS for isotopic analysis.
  • TC/EA
    • The Temperature Conversion Elemental Analyzer is used to analyze oxygen and hydrogen isotopes in wood, cellulose, soil, and liquid samples. The sample is combusted at 400-1500°C in the presence of glassy carbon to produce CO and H2 for isotopic analysis.
  • Carlo Erba EA
    • The Carlo Erba Elemental Analyzer is primarily used to analyze nitrogen, carbon, and sulfur isotopes in wood, soil, animal tissue, and organic extractions. The sample is combusted at 1200°C in the presence of chemical catalysts to produce CO2, N2, and SO2.
  • HP 5890 + GCC Interface
    • Utilizing the HP 5890 Gas Chromatograph, it is possible to separate individual organic compounds for isotope ratio measurement. The ability to analyze specific compounds is often necessary to understand the complexities of natural systems. The GCC Interface converts each compound into CO2 and N2 through combustion at 940°C.