Detect the presence of metallic iron and iron oxide. Chromium and nickel will not be replaced with the Copper sulfate test solution, forming the distinctive copper color on the surface in this 6 minute test.
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.
The determination of sulfite usually is made only on boiler waters or on waters that have been treated with catalyzed sodium sulfite for corrosion prevention.
