Study of the stability of extractable phosphate content in a candidate reference material using a modified Williams extraction procedure

Abstract

Extraction schemes have been widely used to study the environmental behaviour of phosphate in soils and sediments. Owing to the variety of extraction methods, the results are not comparable, as they are highly dependent on the procedure. Moreover, the lack of suitable reference materials for this type of analysis makes it difficult to monitor the quality of measurements. In 1996, the European Commission, within the Standards, Measurements and Testing Programme (formerly Community Bureau of Reference, BCR), started a project to harmonise the methodology and to produce certified reference materials. This paper presents the work carried out to prepare a sediment sample to be analysed using a modified Williams extraction procedure adopted by a group of European experts. The studies of homogeneity and stability with time of the extractable phosphate content in the sample are also reported.

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