Total Nitrogen and Carbon
Carbon and Nitrogen Analysis (CN)
The Thermo Scientific FlashSmart Elemental Analyzer determines total carbon (%C) and total nitrogen (%N) in solid samples using high-temperature dry combustion. Samples are combusted at temperatures above 1000 °C in the presence of oxygen and catalytic reagents. Carbon is quantitatively converted to carbon dioxide (CO₂), and nitrogen-containing compounds are converted to nitrogen oxides (NOₓ). The combustion gases pass through a reduction column, where excess oxygen is removed and NOₓ is reduced to nitrogen gas (N₂). The resulting CO₂ and N₂ gases are separated by gas chromatography and detected by a thermal conductivity detector (TCD). The instrument software then calculates and reports total %C and %N.
Total Carbon and Nitrogen Sample Preparation Procedures
Total N and C in Soil 1. Dry 20 g of the homogenized soil sample at 55°C for one week. 2. Pass dried soil through a 2mm sieve. 3. Place dried and sieved sample in a large coin envelope labeled in pencil with the researcher’s initials and sample ID. 4. Grind soil samples using a ball-mill grinder for 1-3 Minutes. 5. Put ground soil samples in a coin envelope and dry for >1 day at 55°C 6. Transfer dried samples to the desiccator. 7. Weigh ~ 50.000-60.000 mg of soil into tin capsules using a microbalance (20-30 mg for more organic soil). 8. Fold the tin capsule to eliminate air in the sample, forming a square shape. 9. Enter weights and sample IDs into the spreadsheet.
| CN Solid Analysis ($/Sample) | TOC/TN Solid Analysis ($/Sample) | Note | ||
|---|---|---|---|---|
| Internal Academic | $6.00 | $14.00 | prepared samples only | |
| External Academic | $9.00 | $21.00 | prepared samples only | |
| External Market | $18.00 | $41.00 | prepared samples only |
*For the facility to perform processing and analysis, please contact the facility manager for sample processing details and rate adjustments for samples that have been processed and prepared by researchers.
