Speciative determination of phosphorus in environmental water by the isotope exchange method

An isotope exchange method for the speciative determination of phosphorus (PO ₄ ^3– , PO ₃ ^3– and total P) in natural water samples is proposed by using the exchange system of moly bdophosphate in the aqueous phase and tetraphenylarsonium molybdophosophate in the organic phase. In this exchange system, only PO ₄ ^3– exchanges and is determined. When the sample water is treated with Br₂ water in advance, the amount of PO ₄ ^3– +PO ₃ ^3– can be obtained. When the sample is treated with H₂SO₄ and HNO₃, then the amount of total P can be determined.