CN Laboratory

The total carbon and nitrogen analyzer is the most heavily used instrument in the NREL analytical laboratory. Over the last five years, researchers from NREL and seven other departments in three CSU colleges have averaged about 18,000 samples per year. Scientists and students from six other universities and three federal agencies have also utilized the instrument.

The instrument is a Leco Tru-Spec (Leco Corp., St. Joseph, MI, USA). It is a dry combustion type with infrared detection for carbon and thermal conductivity detection for nitrogen. It is computer driven with an interfaced balance and a 30 position auto-sampler, which allows up to 2 hours of unattended operation.

The instrument is primarily used to analyze soil and vegetation samples although it has also been used for fertilizer, animal feeds, animal tissue, plant litter, fecal matter, and wastewater effluents.

The nominal sample size is 0.1 gram for vegetation and 0.2 gram for soils. Samples up to 0.5 gram of vegetation or 1.0 gram of soil may be analyzed. The detection limit is approximately 100 ppm at a 1 gram sample size. Typical precision is a coefficient of variation of about 2.5% at nominal sample size (assuming %C = 2.5 and %N= 0.25 for soils, %C = 42 and %N = 2.5 for plants, lower concentrations will have lower precision).

Analysis time is 4 minutes per sample allowing up to 100 samples to be analyzed per day.

For More Information: Contact the facility manager, Dan Reuss, Telephone: 970-491-5573 or email This e-mail address is being protected from spambots. You need JavaScript enabled to view it

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