|Range||MDL||Method||Kit Catalog No.||Refill Catalog No.|
|0-2.5 ppm as N||0.2 ppm||Azo Dye Formation||K-7004||R-7002|
|0-80 ppm as N||4 ppm||Azo Dye Formation||K-7004D||R-7002D|
|0-170 ppm as N||10 ppm||Azo Dye Formation||K-7004A||R-7002A|
|0-300 ppm as N||20 ppm||Azo Dye Formation||K-7004B||R-7002B|
|0-3000 ppm as N||200 ppm||Azo Dye Formation||K-7004C||R-7002C|
|250-2500 ppm as NaNO₂||250 ppm||Ceric Sulfate Titrant with Ferroin Indicator||K-7025|
|500-5000 ppm as NaNO₂||500 ppm||Ceric Sulfate Titrant with Ferroin Indicator||K-7050|
|Range||Method||Kit Catalog No.|
|0-1.00 ppm as N||Azo Dye Formation||K-7003|
Nitrite, an intermediate in the nitrogen cycle, is formed during the decomposition of organic matter but readily oxidizes to form nitrate. These processes occur in wastewater treatment plants, water distribution systems, and natural waters. Nitrites are useful as corrosion inhibitors, preservatives, pigments, and in manufacturing many organic preservative chemicals. A Maximum Contaminant Level of 1 mg/L has been established by the USEPA for nitrite-nitrogen in drinking water.
Azo Dye Formation Method
Reference: APHA Standard Methods, 22nd.ed., Method 4500-NO2¯ B- 2000. USEPA Methods for Chemical Analysis of Water and Wastes, Method 354.1 (1983).
Nitrite diazotizes with a primary aromatic amine in an acidic solution to produce a highly colored azo dye. The intensity of the color is directly proportional to the concentration of nitrite in the sample. Nitrate will not interfere. Results are expressed as ppm (mg/L) NO2-N.
The Ceric Sulfate Titrimetric Method
Reference: Developed by CHEMetrics, Inc.
Ceric sulfate is the titrant and ferroin is the end point indicator. The method is free from glycol interference in samples that contain up to 75% glycol, making it particularly applicable to systems that contain nitrite corrosion inhibitors. Results are expressed as ppm (mg/L) NaNO2.