What method I could in a academic chemical laboratory to determine the nitrogen content in water?
How could I then determine the quality of the water?
The easiest way is by color comparision. For more information, please refer to:
There are many ways of measuring nitrogen forms. Total nitrogen can be determined by adding chemicals to convert all of the nitrogen forms in a sample to nitrate, and then measuring nitrate concentration. Nitrate and nitrite can be measured together or separately. Nitrate and nitrite are most often measured using a colorimetric method, which means the color of treated sample reflects the concentration of the ...
This response provides guidelines on determining nitrogen content in water and the quality of that water.