This International Standard specifies a method for the determination of total nitrogen after inline UV digestion, in various types of waters, such as ground, drinking, surface, and waste waters, in mass concentrations ranging from 2 mg/l to 20 mg/l for total nitrogen, all in the undiluted sample. Other mass concentration ranges are possible, provided the upper limit of the concentration range is exactly 10 times the lower limit (e.g. 0,2 mg/l to 2,0 mg/l). The range of application can be changed by varying the operating conditions. NOTE Sea water can be analysed with changes in respect to sensitivity and adaptation of the carrier solution and calibration solutions to the salinity of the samples.