SPECIATION OF DISSOLVED PHOSPHORUS IN ENVIRONMENTAL-SAMPLES BY GEL-FILTRATION AND FLOW-INJECTION ANALYSIS

A study of the factors affecting separation and detection of dissolved organic and inorganic phosphorus species found in waters and sediment s is reported. The system involved the use of gel filtration and flow injection analysis (FIA). Orthophosphate and myo-inositol hexakisphosp hate, as model solutes representative of low molecular weight P (LMWP) and high molecular weight P (HMWP), were separated on a Sephadex G25 column incorporated into a flow-injection manifold which utilized phot o-oxidation and spectrophotometry for detection of dissolved reactive phosphorus (DRP) and dissolved organic phosphorus (DOP). The influence of eluent pH and ionic strength on adsorption and anionic exclusion o f the model solutes is described, and the optimum eluent composition a nd sample size are described. The method was used to determine LMWP an d HMWP in natural and waste waters, and in sediment extracts. Potentia l limitations of this approach are discussed.