ISO 6878:2004规定了正磷酸盐、溶剂萃取后的正磷酸盐、水解磷酸盐加正磷酸盐和分解后总磷的测定方法。 该方法适用于所有类型的水，包括海水和废水。可在不稀释的情况下测定此类样品中0005 mg/l至0.8 mg/l范围内的磷浓度。 溶剂萃取程序允许测定较小的磷浓度，检测限约为0000 5 mg/l。

ISO 6878:2004 specifies methods for the determination of orthophosphate, orthophosphate after solvent extraction, hydrolysable phosphate plus orthophosphate, and total phosphorus after decomposition. The methods are applicable to all kinds of water including seawater and effluents. Phosphorus concentrations within the range of 0,005 mg/l to 0,8 mg/l may be determined in such samples without dilution. A solvent extraction procedure allows smaller phosphorus concentrations to be determined with a detection limit of about 0,000 5 mg/l.