Sequential extractions for determination of cadmium distribution in coal fly ash, soil and sediment samples Original Research Article

A sequential extraction scheme has been applied to the determination of binding forms of trace cadmium in three reference materials: coal fly ash (NBS 1633a), soil (NIST 2709) and river sediment (CRM 320). The sum of the cadmium present in the individual fractions shows a good agreement with the certified value of total cadmium content. The extraction efficiency is higher than 85%. The determinations of cadmium in the different leachates have been made by graphite furnace atomic absorption spectrometry (GFAAS). The proposed method provided good results using the direct analysis with synthetic standards as well as using the standard addition method. The extractable cadmium gives information about the binding forms of this element in these reference materials (nowadays without certification).