This international standard specifies a method for the determination of nitrite(N), nitrate(N) or the sum of both (nitrite/nitrate(N)), in various types of waters (such as ground, drinking, surface and waste waters) in mass concentrations ranging from 0,01 mg/l to 1 mg/l for nitrite(N) and from 0,2 mg/l to 20 mg/l for nitrite/nitrate(N), both in the undiluted sample.