An evaluation of the efficiency of the alkaline persulphate digestion method for the determination of total phosphorus in turbid waters

The use of an alkaline persulphate digestion procedure has been found to be suitable for the determination of total phosphorus in turbid waters. The procedure was evaluated by analysis of suspensions of standard reference materials (NIES No. 3 Chlorella and NIES No. 2 Pond sediment) and the analysis of model phosphorus compounds added to lake water. Recoveries of phosphorus from suspensions (up to 100 μgP/I) and phosphorus compounds added to lake water were 92–109% and 94–103%, respectively. When compared with the APHA-AWWA-WPCF nitric-sulphuric acid digestion procedure no significant difference between the two digestion procedures was found at the 95% confidence interval.