engleski

Application of plate theory at the calcium-strontium chromatographic separation

The complete separation of strontium from calcium is important for both an ion-chromatographic determination of these elements and the determination of low concentrations of radioactive strontium in natural samples. In the determination of low concentrations of radioactive strontium in samples such as drinking water, milk etc., strontium is to be separated from large amounts of calcium and all other elements. However, due to their very similar chemical behaviour, calcium and strontium are difficult to separate from each other. For that reason, cation exchange columns and eluents with complexing agents are most frequently used for their separation. The separation itself is carried out by gradient eluting with a strict control of pH. In recent time other methods of their separation on the columns filled with an extraction-chromatographic material have been developed as well. Furthermore, there is also a method of their separation on the columns filled with strong base anion exchangers in nitrate form with alcohol solutions of nitric acid. In this way, calcium and strontium may be separated from each other in all concentration ratios Ca/Sr from 1:1 to 100:1. Therefore, this paper presents the separation of calcium and strontium on the columns filled with strong base anion exchangers with alcohol solutions of nitric acid, as well as the application of the Glueckauf plate theory. Furthermore, it will be shown how the separation of calcium from strontium and yttrium may be simulated by means of experimentally determined breakthrough curves and the plate theory. The coincidence between the simulated and the experimentally obtained separation curves will also be shown, as well as the possibility of application of this model for the creation of a method of the isolation of radioactive strontium from a real sample.

Plate theory; calcium-strontium; separation

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