Total Nitrogen and Carbon

What is total nitrogen and carbon?

Total nitrogen and carbon is, quite simply, the total amount of nitrogen and carbon in a sample regardless of what form it’s in – whether it be protein, nucleic acid, fatty acid, etc…

How is total nitrogen and carbon measured?

Measuring nitrogen and carbon is very simple. A small amount of sample is loaded into a small tin cup (this just acts as a container), and then the sample is dropped into a special machine called an elemental analyzer. As soon as the sample drops into the elemental analyzer, it’s immediately burned up and converted to a gas form. The machine measures the concentration of gases and can determine how much nitrogen and carbon is in the sample.

Why is it important to measure total nitrogen and carbon?

Nitrogen itself is a proxy for the protein content – if we multiply the % nitrogen in a sample, this actually gives us an estimate of the total protein content, which is what this research project is all about.

By comparing the ratio of carbon:nitrogen, we can get another picture of how much protein is in a sample. Early on in the growing season plants have the greatest concentration of protein and the lowest concentration of fiber (a compound with lots and lots of carbon), so the C:N ratio is very low. By the end of the season though, there is very little protein and a lot of fiber so the C:N ratio is very high.