Stable Isotope Research Unit

The Stable Isotope Research Unit contains two PDZ-Europa 20/20 Isotope Ratio Mass Spectrometers. Prep units include a Sercon GSL with Gilson gas autosampler for 13C, 15N, and 18O anlaysis of gas samples and combustion of solid and liquid samples for 13C and 15N analysis; a Europa SL with TCD for combustion of solid and liquid samples; a Europa TG gas purification module for trace gas analysis; and an Agilent 6890 GC with a PDZ-Europa Orchid combustion interface for compound-specific isotope analysis. The Agilent capillary GC is used primarily for the separation of fatty acid methyl esters (FAME) but can also be used for the separation of other carbon containing compounds such as carbohydrates and amino acids.


The PDZ-Europa 20/20 has a precision of + 0.3‰ 15N and + 0.2‰ 13C at natural abundance levels.

Applications of Analysis

  • Agronomy
    • Fertilizer Recovery
    • C Cycling and Sequestration
    • Soil N cycling
  • Marine Science
    • Nitrogen Recycling
    • Ammonium Regeneration
  • Nutrition
    • Protein Metabolism
    • Food Adulteration
  • Environment and Ecology
    • Nitrate in Groundwater
    • Photosynthesis and Gas Exchange
    • Trace Gas Analysis


Analytical Procedures

CF-IRMS (e.g. Sercon GSL prep unit linked with IRMS)

Sample material is ground to a fine powder and weighed into tin capsules. Liquid samples are dried on to filter papers and loaded into tin capsules. During operation, the tin capsule falls into a combustion tube as a pulse of O2 is injected. Combustion products are swept through a purification train by a He carrier gas. The resulting N2 or CO2 is carried to the mass spectrometer by a capillary interface. The signals from the mass spectrometer’s collectors are integrated by a computer.

GC-C-IRMS (Agilent GC linked with IRMS)

Samples are injected onto a GC column for separation. Helium carries the the mixture eluting from the GC to a combustion furnace containing platinum and copper, which converts materials to N2 or CO2. Water is removed with a nafion membrane dryer and the entire gas sample is bled in to the mass spectrometer via a capillary interface. The signals from the mass spectrometer’s collectors are integrated by a computer.


Price and Sample Requirements

Prices updated October 2013.

13C or 15N CF-IRMS (single isotope mode) solid samples basic analysis $ 8.00/sample
13C and 15N CF-IRMS (dual isotope mode) solid samples basic analysis $ 12.00/sample
13C or 15N CF-IRMS gas samples $ 10.00/sample
13C GC-C-IRMS (e.g. FAME) analysis $ 35.00/sample
GC-FID (e.g. FAME) analysis  $ 10.00/sample
Sample weighing and encapsulation $ 2.00/sample
Sample grinding $ 3.00/sample
Acid fumigation (carbonate removal) $ 4.00/sample
Methods development / Consulting on data analysis $ 50.00/hr

All samples should be packaged individually and labeled with a numeric code. Supply us with expected elemental concentration and isotopic enrichment (e.g., % N and atom% 15N). Provide contact and billing information.

    Solid samples - should be dried and ground to pass a 40-mesh screen or better (powdered)

    Solution samples -  should first be dried or diffused onto filter paper disks

    Gas samples - please contact us for information on preparation of gas samples

    FAME or other GC-IRMS samples - please contact us for details

Total price and turn around time vary. Please contact David Myrold with any questions about price or sample requirements.

Stable Isotope Research Unit
Department of Crop & Soil Science
Oregon State University
Ag & Life Sciences Bldg., #3017
Corvallis, OR 97331-7306
(541) 737-5737
FAX (541) 737-5725