Portable flow-injection analyzer for nitrite and nitrate in natural water.

A portable flow-injection analyzer with solid-state spectrophotometric detection for the determination of nitrite and nitrate is described. It utilizes the Griess-Saltzman reaction. The instrument comprises a two-channel peristaltic pump, two six-port injection valves and a mini cadmium column between them. The sample loops were connected serially. The detection limits of the method were less than 7 microg l(-1) for NO2- and 10 microg l(-1) for NO3-.