Nitrate Reductase (NaR) is an enzyme that plays a vital role in plants. NaR is a key enzyme (protein) in the assimilation of nitrate. NaR binds nitrate as its substrate with high specificity.
In a pH stable buffer solution, NaR catalyzes the reduction of nitrate to nitrite using NADH or NADPH as the electron donor to drive the reaction forward to endpoint. It is non-toxic for safe use and easy disposal, unlike outdated methods using cadmium.
The resulting nitrite reacts with the color reagents to form a shade of pink which can easily be compared by the naked eye to the provided 5ppm nitrate standard, the provided color chart in the instructions, or our custom "color slider app" for smartphones and web based browsers.
After the enzymatic reaction occurs, color reagent powder is added to the sample and turns it pink. A darker shade of pink indicates that more nitrate is in the sample.
A photometer capable of reading absorbance at 540nm ± 10nm will provide the most accurate reading of nitrate content, however a nitrate standard curve must be generated using excel or your statistics package to convert the absorbance reading to a ppm reading.
Above information is courtesy of NECi (The Nitrate Elimination Company, Inc.)