APPLICATION OF SOLID-PHASE EXTRACTION TECHNIQUE FOR DETERMINATION OF PHOSPHORUS IN SEDIMENT EXTRACT

A solid-phase extraction technique has been examined for pretreatment of colorimetric determination of soluble reactive phosphorus (SRP) in sediment extracts. The SRP was effectively collected as a molybdophosp horic acid complex by a cartridge column packed with polystyrene divin ylbenzen resin. The complex adsorbed on the resin was eluted with a sm all aliquot (<5 ml) of 0.5 M NaOH solution. The recovered SRP was then determined by the standard molybdenum blue method. Compared with the solvent-extraction technique which has been generally used by previous workers, the present method consists of much easier procedures, and p recision and recovery of this method are sufficiently high. The method was then applied for the determination of iron-bound P (Fe-P) in sedi ment samples from the Tamagawa Estuary. The results suggest that Fe-P in sediments is an important source of P in estuarine and coastal ecos ystems through releasing phosphate to estuarine water with increasing salinity.