Nitrogen is abundant in the Earth’s atmosphere and is present in water as nitrate, nitrogen, and ammonia. Nitrogen is indispensable for plantlife and is a key factor in fertilization. Nitrogen allows the development of the vegetative growth of the plant; in particular, it contributes to lengthening of trunks and sprouts and increases the production of foliage and fruits. This is why nitrogen is one of the three main components of NPK (Nitrogen-Phosphorus-Potassium) fertilizers. However, an excess of nitrogen weakens the plants' structure creating an unbalanced relationship between the leaves and the stalks. In addition, the plant becomes less resistant to diseases.
In winemaking Yeast Assimilable Nitrogen (YAN) also known as Formol Number, is a measurement of Nitrogen in wines. Nitrogenous compounds such as ammonia are essential to the winemaking process. A sufficient concentration of nitrogen must be present in the grape juice for healthy yeast metabolism and an efficient fermentation. Low nitrogen levels can result in slow or incomplete fermentations. When nitrogen availability is too low in wine must, yeast may undergo less efficient, undesirable fermentation pathways yielding hydrogen sulfide, a compound known for its ‘rotten egg’ odor.
In wastewater treatment, Total Nitrogen (TN) is regulated and can be measured by digesting a sample. Total nitrogen includes all forms of nitrogen including from nitrate, nitrite, ammonia, and organically bound nitrogen.
Hanna offers the ability to measure YAN and TN. YAN can be measured by titration while TN is done photometrically with a spectrophotometer or benchtop photometer.
Below are the most common products used for measurement of nitrogen.
Titration systems are available to measure Yeast Assimilable Nitrogen (YAN). These systems include a mini-titrator designed specifically for measuring formol nitrogen in wine. Potentiometric titration systems can measure a wide range of parameters are available; including one that has wine parameters pre-programmed into the meter. The potentiometric titrations systems have a precision dosing pump for precise dosing of a titrant. These systems use a pH probe determine the endpoint.
pH Probes for Titration
Potentiometric titration systems use a pH electrode for determining the pH endpoint of a formol (YAN) titration. The pH probes include the one supplied with the mini-titrator and a pH electrode for wine that uses the Hanna’s Clogging Prevention System (CPS) technology. The CPS technology has a ground glass junction with a movable sleeve that allows for cleaning of any solids.
Solutions for nitrogen measurement include the calibration solution and fill solution for the pH electrode used with the titrators.
Spectrophotometers are available that have nitrogen method in several ranges pre-programmed into the meter. The spectrophotometer offers the highest precision due to the quality of the optical system that has a wavelength accuracy of +/- 1.5 nm. The spectrophotometer allows for custom methods to be used as well.
Wastewater treatment benchtop photometers include the total nitrogen parameter along with other key water quality parameters including COD, nitrate, and ammonia. All benchtop have a digital pH electrode input allowing it to be used as a traditional pH meter.
Reagents for the photometric analysis along with reagents for formol number titration are included in this category.
Accessories include a COD reactor used to digest the sample when measuring total nitrogen by photometric analysis. Other accessories are a fixed range automatic pipette along with replacement parts for the mini-titraor.