Test Method Technical Information


Tests For: Nitrite in natural, drinking and waste waters
Tests Range: 0–0.5 mg/L N (0–1.6 mg/L NO2)
Reagent Chemistry Used: N-(1-naphthyl)- ethylenediamine diazotization
Basis of Test Method: Standard Method 4500-Nitrite-B, US EPA Method 353.
Method Detection Limit*: 0.002 mg/L
Limit of Quantification**: 0.007 mg/L

*The Method Detection Limit (MDL) is defined as the minimum measured concentration of a substance that can be reported with 99% confidence to be different from the method blank results.
**The Limit of Quantification (LOQ) is the smallest quantity that can be detected with reasonable certainty for a given analytical procedure.

Testing for Nitrite

Nitrites are found in natural waters as an intermediate product in the nitrogen cycle. Nitrite is harmful to fish and other forms of aquatic life and the nitrite level must be carefully controlled in water used for fish farms and aquariums. The nitrite test is also applied for pollution control in waste waters, and for the monitoring of drinking water.

The Palintest Nitricol test provides a simple method of measuring Nitrite Nitrogen levels over the range 0 – 0.5 mg/l N. Higher levels can be determined by diluting the sample.

Reagent Chemistry

Nitrites in acid solution react with sulphanilic acid. The resulting diazo compound couples with N-(1-naphthyl)-ethylene diamine to form a reddish dye. The Palintest Nitricol method features a single tablet reagent containing both of these reagents in an acidic formulation. The test is simply carried out by adding a tablet to a sample of the water under test.

The intensity of the colour produced in the test is proportional to the nitrite concentration and is measured using a Palintest Photometer.

EPA, Definition and Procedure for the Determination of the Method Detection Limit, Revision 2, Dec 2016.
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the “Gold Book”).