Determination of 90Sr in aquatic organisms by extraction chromatography: method validation Original Research Article

A method is presented for the determination of 90Sr in plankton and cod matrices using extraction chromatography. The samples were microwave digested using closed-pressurised vessels and the 90Sr was separated by extraction chromatography using a crown ether sorbed on an inert substrate. The separation yield of Sr ranged from 80 to 100%. Separation reproducibility, resin capacity and matrix effect were also investigated. The maximum resin capacity was 8.76 mg of Sr/g of resin. The same resin could be used more than ten times without decrease of performance. Except Ba, which eluted together with Sr, none of the elements studied interfered with the separation of Sr since practically all were washed out before the elution step. A method using 8 M HNO3 as washing agent, before the Sr elution with 0.05 M HNO3, is proposed to remove Ba completely. The separation method was checked with BCR CRM 414 Plankton and BCR CRM 422 Cod Muscle spiked with 90Sr.