The effect of adding a standard on the result of determination of polychlorinated biphenyls in bottom sediment...

Bottom sediments are a very important component of aquatic ecosystems. The sediment matrix is highly diverse and heterogeneous; in consequence, compounds entering the aquatic environment from different sources are considerably enriched at its surface. Bottom sediments are regarded as natural sorbents, since they accumulate many harmful substances, such as heavy metals and stable organic contaminants. Extraction is a key stage in every analytical procedure. It is during this stage that standards are added to samples. Standards are necessary not only for estimating analyte yields but also for validating the whole procedure. The question of the addition of standard substances to sediment samples has not been widely addressed in the subject literature, and yet it is of fundamental importance as regards obtaining reliable results of determinations. This paper describes the results of a study on the effect of standard addition techniques on the results of determination of polychlorinated biphenyls in sediment samples (certified reference material: METRANAL2-river sediment).