Nitrate

Nitrate

Nitrogen is abundant in the Earth’s atmosphere and is present in water in the forms of nitrate, nitrite, and ammonia. Plants use nitrogen as a nutrient to build proteins by tracking it in through their root system. This is why it is important to test soil and irrigation water to determine the optimal level of nitrogen fertilization to obtain the best crop response and avoid over-fertilization. Nitrate-nitrogen tests can be performed year-round, but testing is particularly recommended during spring and late spring, when rainfall and temperature-related bursts of microbiological activity often have great influence on the availability of nitrate-nitrogen.

Nitrate is measured in drinking water. The EPA has a maximum contaminant level 10 mg/L limit of Nitrate as Nitrogen (NO3-N). Similarly, the World’s Health Organization has a limit of 50 mg/L Nitrate (NO3–) in drinking water. Both values are close with the difference being the chemical form. 50 mg/L Nitrate is equivalent to 11.29 mg/L as Nitrate-Nitrogen. Nitrate is monitored due to the effect it has on the oxygen carrying capacity of blood. In infants, if formula is prepared with water that has a high level of nitrates then this can be toxic due to the conversion of nitrate to nitrite. The nitrite reacts with iron in hemoglobin to form methemoglobin. The methemoglobin reduces the blood capacity to carry oxygen resulting in a blue discoloration known as Blue Baby Syndrome or methemoglobinemia.

Hanna Instruments offers a wide variety of instrumentation for measuring nitrate. Products include benchtop and portable pH/ISE meters that can use a liquid membrane nitrate Ion-Selective Electrode (ISE) for direct measurement. Both benchtop and portable meters have the ion charge and molecular weight pre-programmed in order to take ion concentration measurements along with multiple units of measure. The benchtop meters have incremental methods built-in.

Hanna offers a variety of chemical based methods to measure nitrate. Available technologies include Spectrophotometer, benchtop and portable photometers, Checker HC, and chemical test kits. The Spectrophotometer and photometers can display nitrate as Nitrate or as Nitrate-Nitrogen. A marine version of the Checker HC allows for the measurement of nitrate in seawater for the maintenance of a saltwater aquarium.