Which parameter measures oxidized nitrogen species such as nitrate and nitrite?

• A. Nitrate nitrogen content
• B. Nitrite nitrogen content
• C. Nitrate/Nitrite
• D. Total Kjeldahl Nitrogen

Answer: (C)

Oxidized forms of inorganic nitrogen are nitrate and nitrite, and to capture the total amount of these oxidized species you measure them together as nitrate/nitrite. This combined parameter accounts for both NO3- and NO2-, giving a complete picture of the oxidized nitrogen in the sample. If you measure nitrate alone, you miss nitrite; if you measure nitrite alone, you miss nitrate. Total Kjeldahl Nitrogen, on the other hand, targets organic nitrogen and ammonium after digestion, not the oxidized inorganic forms. So the nitrate/nitrite parameter is the best choice for representing the oxidized nitrogen species.