Determination of Nitrate Content in Waste Liquid (Water)—Volumetric Method

This standard specifies a volumetric method for determining nitrate content in waste liquid (water). It applies to nitrate-containing waste liquid (water) generated by printed circuit board production, steel pickling, nitrate nitrogen fertilizer and other industries, with a determination limit of 0.12 g/L expressed as nitrate ion. Samples shall be collected as specified, refrigerated and protected from light, and analyzed within the prescribed period. After necessary dilution and removal of interference from color, organic matter and other substances, nitrate is reduced by ferrous salt in a sulfuric acid system with a molybdate catalyst, then titrated with potassium permanganate standard titration solution for calculation. Blank testing, precision requirements and a recovery range of 90.0% to 110.0% are specified.