The simultaneous analysis of total nitrogen and total phosphorus in natural waters

Abstract Different tests have been made to determine some characteristics of the persulphate oxidation method for the simultaneous determination of total nitrogen and total phosphorus in water. A description of the method is outlined. Results of tests for calibration and capabilities, comparison with a former method using separate determinations, stability of stored samples and the oxidation reagent, as well as the influence of the time elapsed between sampling and cooking, are given. The new method has been used with good results for two years.