Ideal for low- to medium-range colorimetric analysis of water quality

CHEMets® test kits utilize self-filling ampules and vacuum pulls the sample up from a snap cup into the ampule when the tip is broken off. After tilting the ampule several times to mix the sample and reagent and waiting for the color to develop (usually 2 minutes or less), the analyst quantifies the result using the provided cylindrical comparator (for concentrations ≤1ppm) or flat comparator (for concentrations ≥1ppm).

The VACUettes Auto Dilution Method: Hold the ampoule in a horizontal position while the capillary tip contacts the sample (Step 1). After the capillary fills, immerse it in a diluent (usually deionized water); snap the tip off the ampoule (Step 2). The sample and diluent are drawn into the ampoule where they mix with the reagent (Step 3). The resulting color change can then be compared with the flat or round comparator to quantify results (Step 4).

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.

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.