Rapid flow injection analysis method for successive determination of ammonia, nitrite, and nitrate in water by gas-phase chemiluminescence

A flow injection analysis method is presented in which an aqueous sample itself is used as the carrier stream and reagents are injected into this sample stream. Nitrite and nitrate were converted into nitric oxide (NO) in acidic media using iodide and titanium(III) as reducing agents, respectively. Ammonia was reacted with hypochlorite to generate a volatile compound. The NO or the volatile compound was transferred into air in a glass-tube separator and the volatile compound was subsequently converted into NO by combustion at 600 degrees C. The NO was then reacted with ozone and the resulting chemiluminescence was detected. The determination limit was 1x10(-8) M for ammonia and nitrate, and was 1x10(-8) M for nitrite. The total time for the analysis of ammonia, nitrite, and nitrate in one sample was less than 3 min.