Determination of nitrate/nitrite concentration in water by photochemical reduction

摘要: Methods for determining the concentration of nitrates in several types water samples by photochemical reduction without use toxic materials such as cadmium or hydrazine, and having an approximately 100% efficiency are described. A sample (12) mixed with a buffered aqueous solution including ammonium salts EDTA (26) is irradiated (20, 31) using ultraviolet light wavelengths effective conversion nitrate nitrite ions (NOx) to detectable species. The resulting species may be quantitatively determined diazotization sulfanilamide followed coupling N-(1-napthyl)ethylenediamine dihydrochloride (32) which produces water-soluble azo dye magenta color colorimetrically measured at 540 nm (24) from determined. Nitrite present original analyzed unphotolyzed reaction dihydrochloride. When subtracted total concentration,