We have been providing service for
researchers at OSU and beyond
for over 14 years. Price and
turn-around time vary.
Call us for details.

As of April 2007:

Please contact Rockie Yarwood
with any sample inquiries.

Stable Isotope Research Unit
Department of Crop & Soil Science
Oregon State University
Ag & Life Sciences Bldg., #3017
Corvallis, OR 97331
(541) 737-5744
FAX (541) 737-5725
rockie.yarwood@oregonstate.edu

Stable Isotope Research Unit

Oregon State University

The Solid/Liquid Preparation module linked to a 20-20 Isotope Ratio Mass Spectrometer.

The Stable Isotope Research Unit contains two mass spectrometers; a Europa Scientific Tracermass Isotope Ratio Mass Spectrometer and a newer PDZ Europa Hydra 20/20 Isotope Ratio Mass Spectrometer. We are equipped with both a solid and a capillary GC preparation unit. The Europa Scientific Roboprep C/N analyzer is designed for the automated analysis of ¹⁵N and ¹³C in solid biological, environmental, and marine science samples and can be linked to either mass spectrometer. The system utilizes a Dumas combustion/reduction apparatus, thereby eliminating the need for lengthy Kjeldahl digests. The Agilent capillary GC is used primarily for the separation of fatty acid methyl esters but can also be used for the separation of other carbon containing compounds such as alkanes and amino acids. This unit works in conjunction with the PDZ Europa mass spectrometer.

Analytical Procedures

C/N Analyzer linked with MS

Ground material will be powdered 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-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 Naffion membrane and the entire gas sample is bled in to the mass spectrometer via a capillary interface.

Precision

The Tracermass system is capable of analyzing with a precision of + 0.8‰ ¹⁵N and 0.5‰ ¹³C, and the Hydra 20-20 has a precision of + 0.3‰ ¹⁵N and + 0.2‰ ¹³C at natural abundance levels.

Applications

• 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

Sample requirements

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

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

Solution samples

• 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

Please contact us if your samples do not meet these requirements.